SCIENCE 6

CHAPTER 1 THE CIRCULATORY SYSTEM LESSON 1: PARTS OF THE CIRCULATORY SYSTEM The Circulatory system is the body’s transport system. It transports water, nutrient, and oxygen throughout the body. It collects waste materials from the cells and delivers them to the excretory organs. It also helps regulate body temperature and protects the body from disease.

The circulatory system is made up of the heart, blood and blood vessels.

The Heart The heart is a muscular organ that pumps blood throughout the body. It is located between the lungs and behind the breastbone. Its apex is slightly slanted to the left as shown in Figure 1.2

The human heart has four chambers that work together to push blood.

The upper thin-walled chambers on each side are the atria. The atria receive and collect blood. From atria, blood flows through each of the two lower chambers called ventricles. The ventricles have thicker walls than the atria.

The left ventricle is much more muscular than the right ventricle because it needs to pump blood to all body parts.

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Can you feel your heartbeat? When the heart receives blood, it expands and contracts, squeezing the blood out of its chambers. Te expansion and contraction of the heart cause a heartbeat. Normally the heart of an average adult beats about 75 times per minute or 4,500 times per hour.

The heart also has valves that keep blood flowing in one direction and prevent backflow. The opening and closing of the valves produce sounds like ’’lub-dub. The ‘’lub’’ sound is caused by the vibrations of the mitral and tricuspid valves as they close. The ‘’dub’’ sound is caused by the closing of the aortic and pulmonary valves.

The Blood The Blood is the red liquid that carries oxygen and essential nutrients to all body tissues. it also carries carbon dioxide and other waste products away from the cells and back to the lungs to be exhaled.

The human body contains approximately 5 liters of blood. Blood makes up about 9% of a person’s total body weight.

When a blood sample is transferred to a test tube and is prevented from clotting, its solid component sinks to the bottom of the test tube, while its liquid component floats on top. The yellowish liquid component of the blood is called plasma. It is made up of water, proteins, and other substances.

The solid component of blood consists of three blood cell types-red blood cells, white blood cells and platelets. Blood cells and platelets. Blood cells are made in the bone marrow. About 100 mllion blood cells are produced in the human body every minute.

Figure 1.4. composition of blood Young Ji International School / College

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Red Blood cells (RBCs) also known as erythrocytes, are the most abundant cell type in the blood. A red blood cell is shaped like a doughnut with flattened center instead of a hole. Red blood cells carryout the exchange of oxygen and carbon dioxide between the lungs and the body tissues. A red blood cell has an iron-containing protein called haemoglobin. Hemoglobin attracts oxygen from the lungs and picks up carbon dioxide from the cells.

Oxygen attached to haemoglobin gives red blood cells their color. The body produces about 200 billion new red blood cells every day, and each has a life span of 120 days.

White blood cells (WBCs), also called leukocytes, fight body infections. They act like soldiers attacking and destroying germs that enter the body. They are larger but less in number compared to red blood cells. They also have a shorter life span than red blood cells. Each white blood cell has a life span of about three days.

Platelets are the smallest cells in the blood. They are also called thrombocytes. They are about one-third in size compared to red blood cells.

They release chemicals that cause tiny fibers to form, thus creating a blood clot. They can survive for a period of five to nine days. Without platelets, a wounded person would bleed to death. When a blood vessel is cut, platelets rush to the damaged vessel to create a plug. They swell into irregular shapes, grow sticky, and clog at the cut. Clotting stops the bleeding and creates a scaffold on which to build a new tissue.

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Blood Vessels Blood vessels are tube-like structures through which blood circulates.

The three types of blood vessels are arteries, capillaries and veins.

The arteries carry blood away from the heart. The largest artery in the body is the aorta. Arteries have a thick muscular wall to withstand the increase in blood pressure coming from the heart. The blood passes through smaller arteries. The smallest arteries called arterioles lead to tiny capillaries.

Capillaries are the thin-walled blood vessels that form a network between the organs and tissues of the body. These are the smallest blood vessels in the body. The walls of the capillaries allow oxygen and nutrients to enter from the blood into the cells, and also allow carbon dioxide and other waste products to exit from the cells and enter the blood. This process is called diffusion.

Diffusion is the movement of tiny particles from an area of higher concentration to an area of lower concentration. The concentration of nutrients and oxygen in the blood is higher than in the surrounding cells. Thus, oxygen and nutrients diffuse from the capillaries into the cells. On the other hand the concentration of waste products and carbon dioxide in the body’s cells is higher than in the capillaries. Thus, waste products diffuse from the cells into the capillaries.

The capillaries connect the arteries to the veins. Veins carry blood back to the heart. They have thinner walls from arteries. The superior and inferior Young Ji International School / College

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vena cavae are the biggest veins in the body. Both carry blood to the right side of the heart.

Blood should flow only in one direction. Veins have leaflet valves that prevent the blood from flowing backward.

Fig. 1.8 Comparison between an artery and a vein

Activity Identify what is being asked in each statement .Choose from the list below.

Aorta

blood

capillaries

Platelets

plasma

valve left ventricle

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heart

haemoglobin white blood cells

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____________1. A muscular organ that pumps blood throughout the body ____________2. A thick-walled chamber that pushes blood out of the heart into the main artery. ____________3. The largest artery connected to the heart. ____________4. The red fluid that distributes nutrients and oxygen to the cells, and collects waste products from them ____________5. A flap of tissue that prevents blood from flowing backward ___________6. The smallest blood vessels where diffusion takes place ___________7. The blood cells that protect the body against diseases and infections. __________8.The liquid blood component that carries nutrients, hormones and other substances __________9. The blood cells that form blood clots _________9. The iron-containing protein that binds with oxygen

LESSON 2: BLOOD CIRCULATION

Circulation is the movement of blood as it distributes nutrients and oxygen throughout the body and collects waste products from body cells. It can be divided into two phase: a. pulmonary circulation, and b. The systemic circulation Pulmonary circulation is the movement of blood from the heart, to the lungs, and back to the heart again. This is just one phase of the overall circulatory system.

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The veins bring waste-rich blood back to the heart, entering the right atrium throughout two large veins called vena cavae. The right atrium fills with the wasterich blood and then contracts, pushing the blood through a one-way valve into the right ventricle. The right ventricle fills and then contracts, pushing the blood into the pulmonary artery which leads to the lungs. In the lung capillaries, the exchange of carbon dioxide and oxygen takes place. The fresh, oxygen-rich blood enters the pulmonary veins and then returns to the heart, re-entering through the left atrium.

The oxygen-rich blood then passes through a one-way valve into the left ventricle where it will exit the heart through the main artery, called the aorta. The left ventricle's contraction forces the blood into the aorta and the blood begins its journey throughout the body.

The one-way valves are important for preventing any backward flow of blood. The circulatory system is a network of one-way streets. If blood started flowing the wrong way, the blood gases (oxygen and carbon dioxide) might mix, causing a serious threat to your body.

Systemic circulation supplies nourishment to all of the tissue located throughout your body, with the exception of the heart and lungs because they have their own systems. Systemic circulation is a major part of the overall circulatory system.

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The blood vessels (arteries, veins, and capillaries) are responsible for the delivery of oxygen and nutrients to the tissue. Oxygen-rich blood enters the blood vessels through the heart's main artery called the aorta. The forceful contraction of the heart's left ventricle forces the blood into the aorta which then branches into many smaller arteries which run throughout the body. The inside layer of an artery is very smooth, allowing the blood to flow quickly. The outside layer of an artery is very strong, allowing the blood to flow forcefully. The oxygen-rich blood enters the capillaries where the oxygen and nutrients are released. The waste products are collected and the waste-rich blood flows into the veins in order to circulate back to the heart where pulmonary circulation will allow the exchange of gases in the lungs.

During systemic circulation, blood passes through the kidneys. This phase of systemic circulation is known as renal circulation. During this phase, the kidneys filter much of the waste from the blood. Blood also passes through the small intestine during systemic circulation. This phase is known as portal circulation.

During this phase, the blood from the small intestine collects in the portal vein which passes through the liver. The liver filters sugars from the blood, storing them for later.

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Pulse Rate Everytime a heart beats; it exerts a pressure on the blood vessels causing them to stretch and bulge. The stretching and bulging of an artery is called pulse. The pulse can be felt in different parts of the body as in the temple, neck, inner side of the wrist and elbow and behind the knee. When you do strenuous activity you heart beats faster because your body needs more oxygen and nutrients to produce more energy.

Activity Trace the flow of blood through the heart and body by numbering the following in the correct order. _______ Deoxygenated blood enters the right atrium through the superior vena cava and inferior vena cava. _______ Deoxygenated blood enters the right ventricle _______The pulmonary artery carries the deoxygenated blood to the lungs, where it absorbs oxygen. _______as the right ventricle contracts, it forces the deoxygenated blood into the pulmonary artery _______oxygenated blood enter the left atrium _______Oxygenated blood passes through the aorta and flows through the other parts of the body. _______Oxygenated blood flows into the left ventricle _______Oxygenated blood returns to the heart through the pulmonary veins.

B. 1. How are heartbeats related to the pulse?

2. Why does the heart beat faster when you exercise? ____________________________________________________________________ _______________________________________

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LESSON 3: COMMON AILMENTS AFFECTING THE NERVOUS SYSTEM Anemia is a condition that develops when your blood lacks enough healthy red blood cells or hemoglobin. Hemoglobin is a main part of red blood cells and binds oxygen. If you have too few or abnormal red blood cells, or your hemoglobin is abnormal or low, the cells in your body will not get enough oxygen. Symptoms of anemia -- like fatigue -- occur because organs aren't getting what they need to function properly.

Forms of anemia:  Iron-deficiency anemia, occurs when your body doesn’t have enough iron to produce haemoglobin. 

Pernicious anemia, in this type the intestinal wall does not absorb enough vitamin B12 or folic acid, which is essential for the formation of red blood cells.



Aplastic anemia, the bone marrow does not produce enough red blood cells.



Sickle cell anemia is an inherited form of anemia characterized by irregularly shaped red blood cells. This affects the ability of red blood cells to transport oxygen. The irregular shape of the sickle cells can cause internal bleeding as the walls of the blood vessels are damaged. The sickle shaped cells can also block blood flow to other tissues.

Fig. 13. Sickle cell RBCs damage the blood vessel

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Atherosclerosis Atherosclerosis is the clogging and hardening of the arteries due to a build-up of cholesterol, fat, and other substances. These substances may form plaques that can stay on the artery walls, and interfere with the flow of blood.

This condition can lead to stroke or heart attack.

Fig. 14. A blood vessel with cholesterol on its lining

Congenital heart disease Refers to a heart defect present at birth in which the heart fails to develop normally. The infant’s body tissues receive inadequately oxygenated blood because the heart does not blood into the lungs properly.

Coronary heart Disease Coronary heart disease is a narrowing of the arteries that supply blood to the heart muscle. It may be caused by atherosclerosis, when fatty substances accumulate on the artery walls. If one of the arteries becomes severely or totally blocked with fatty deposits, blood cannot flow freely to the heart. When the heart muscle does not get the nutrients and oxygen it needs due to narrowed or blocked artery, it becomes injured. If the injury affects a bigger area, the heart may not be able to pump blood. When this happens, a heart attack occurs.

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Figure 15 Atherosclerosic plaques may cause coronary heart disease Hypertension Hypertension is commonly known as high blood pressure. It is sometimes called the ‘’silent killer’’ because it often has no symptoms but it damages vital organs throughout the body. In hypertension, the pressure in the arteries becomes great, causing the heart to work harder in order to keep blood flowing through blood vessels.

When the walls of the artery cannot accommodate the high pressure of blood coming from the heart, the artery will burst. As a result, the blood cannot reach the different tissues in the body. When the damaged artery is in the area of the brain, a stroke occurs. A heart attack occurs when the flow of the blood is blocked due to cholesterol plaques or to the presence of a blood clot. The heart muscle is deprived of oxygen and portions of the heart become weak.

Leukaemia Leukaemia is one of the cancers of the blood. A person with leukaemia suffers from an increasing amount of abnormal white blood cells that interfere with the production of normal white blood cells. Since white blood cells are responsible for fighting disease-causing invaders, a person with leukaemia has low resistance to infection. This disease may be hereditary. It may also be caused by excessive exposure to x-rays and other types of radiation.

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Varicose veins Varicose veins are veins that have become stretched and swollen with blood. Varicose veins develop when the leaflet valves of veins become weak and ineffective. The blood that should be moving toward the heart may flow backward. The backflow enlarges the veins and they become varicose. Simple varicose veins in the legs may be treated by wearing support stockings or elevating the legs. Large varicose veins may require energy.

Fig. 1.17 legs with varicose veins

Activity A. Identify the term being described by each statement. Choose you answers from the box. Write the letter of the correct answer on the blank. a. sickle cell anemia b. congenital heart disease c. coronary heart disease d. heart attack e. hypertension

f. leukemia g. stroke h. varicose veins i. aplastic anemia j. atherosclerosis

_____1. It is a condition in which the blood pressure is higher than normal. _____2. It is a disorder caused by the failure of the valves in the veins to prevent the backward flow of blood.

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_____3. It refers to the accumulation of fatty deposits on the artery walls. _____4. It involves one or more heart defects present at birth. _____5. It occurs when the heart muscle does not receive sufficient supply of oxygen and nutrients. _____6. It involves damage to arteries in the brain. _____7. It is a condition in which the bone marrow does not produce enough red blood cells. _____8. It is a form of cancer characterized by uncontrolled production of abnormal white blood cells. _____9. It is characterized by the presence of irregularly shaped blood cells. _____10. It occurs when one of the coronary arteries is suddenly blocked.

LESSON 4: KEEPING THE CIRCULATORY SYSTEM HEALTHY The circulatory system performs important functions in the body. Taking good care of it will lead to a healthier heart. Practicing good health habits can help prevent illness and disease.

Eat a balanced meal Eating a balanced meal means eating the right kind and right amount of food.

Eat more vegetables and fruits. Iron-rich foods like soybeans, flour, liver and molasses are good for the formation of haemoglobin. Folic acid which is found in green and leafy vegetables, aids in the production of red blood cells.

Reduce intake of foods rich in fats and cholesterol because they increase the risk of developing atherosclerosis. Reduce salt intake as salt promotes high blood pressure. Choose carefully the food you eat.

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Exercise regularly Exercise helps lower the risk of heart disease and improves blood circulation.

As you exercise, you burn fats and prevent cholesterol build up in your blood vessels.

Physical activities help clean up your bloodstream and remove toxins from your body.

The heart pumps faster during exercise allowing your blood to circulate and your cells to receive enough oxygen and nutrients.

Dancing, jogging, and playing basketball are some forms of exercise.

Rest and Relax Tension and worries can cause high blood pressure. Learn to relax to relieve stress. Rest when you are tired.

Sleeping is the best form of exercise. When you sleep, your cells regenerate, the damaged tissues are repaired, and your immune system is strengthened. Sleep at least eight hours a day and get energized for the next day.

Keep your surroundings clean Some disease of the circulatory system is caused by a dirt environment.

Avoid staying in areas with plated air. Air pollutants, when inhaled, are absorbed by the blood. Toxic substances that collect in the blood cause diseases.

Activity A. Write true if the practice is good for the circulatory system and false if it is not. _______1. Exercise regularly. _______2. Find time to relax. _______3. Eat fatty and salty food. _______4. Have a regular blood pressure check up. _______5. Eat vegetables and fruits. _______6. Smoke cigarettes. _______7. Eat the right t kind and amount of food. _______8. Sleep late at night. _______9. Develop good study habits to avoid stress and tension during examinations. _______10. Eat only hamburger and fried chicken ever day.

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LESSON 5: PARTS OF THE NERVOUS SYSTEM The Nervous system controls, monitors, and coordinates all the activities of the body and the processes that occur within the body.

Figure 2.1 The nervous system and its major part The nervous system consists of the brain, spinal cord and nerves.

Parts of the Nervous System Central Nervous System Your central nervous system is made up of your brain and spinal cord.

The central nervous system is the control center for all incoming and outgoing messages. It receives all information about your body, evaluates it, and integrates a response that is passed along to other organ systems. The central nervous system is the place where memories, knowledge, thoughts,

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and emotions are formed. It is also responsible for coordinating the movements of your muscles.

Peripheral Nervous System Your peripheral nervous system consists of the nerves that extend out from your spinal cord to your arms, legs and trunk, like a two-way street travelling to and from your central nervous system. This allows information to be passed to all parts of your body.

The Brain The job of your brain is to send outgoing messages to your body and interpret incoming messages from your body. It is protected by a bony case, your skull, and is divided into three main parts: the cerebrum, the cerebellum, and the brain stem.

Cerebrum Your cerebrum is located above your cerebellum and is the largest part of your brain. It consists of two halves (also known as hemispheres) that are in charge of different bodily functions. The left hemisphere is responsible for speech, language, and hand movements while the right hemisphere is responsible for hearing, touch, and balance. Both hemispheres communicate with each other to accomplish all of these functions, along with memory, emotions, and eyesight. The large size and interpretation capacity of the cerebrum is what gives humans their intelligence and ability to think critically.

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Cerebellum Your cerebellum is a fist-sized structure located at the rear base of your cerebrum. Its main function is to regulate coordination and balance by directing groups of muscles during fine motor movements, and controlling larger muscles to maintain stability and posture. The cerebellum functions to make movements smooth, not jerky.

Brain Stem Your brain stem lies at the base of your brain, connecting the two hemispheres of the cerebrum and attaching your brain to your spinal cord.

Your brain stem is a relay center for incoming messages and it controls unconscious bodily functions that you do not have to think about, such as your heart rate and breathing. Messages from sensory organs, like your eyes, ears, heart and lungs travel to the brain stem, where the information is integrated into a response and then sent to other parts of your brain.

Neurons These are nerve cells. A neuron is an electrically excitable cell that processes and transmits information by electrical and chemical signalling.

Chemical signalling occurs via synapses, specialized connections with other cells. Neurons connect to each other to form networks. A typical neuron possesses a Dendrites, conducts messages from other neurons to the cell body. Cell body (often called the soma), contains the nucleus and other organelles that create chemicals necessary for transmitting messages. And a long branch , called axon ,carries messages from the cell body to another neuron.

Dendrites are filaments that arise from the cell body, often

extending for hundreds of micrometers and branching multiple times, giving rise to a complex "dendritic tree". An axon is a special cellular filament that arises from the cell body and travels for a distance of up to a meter.

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Spinal Cord Your spinal cord is the main pathway for signals to enter and exit your brain. It is essentially a cord of neurons that runs down from the base of your skull to your tail bone. To protect this important structure, a series of bones called vertebrae surround your spinal cord and make up your backbone.

Nerves moving from this system out to your body are not part of the central nervous system, but instead belong to your peripheral nervous system.

Figure 2.4 The spinal cord

The spinal cord has two main functions. First, it relays the messages from the brain to the different parts of the body, and vice versa. Another function of the spinal cord is to control some important body actions that do not involve thinking. These actions are called reflexes. A reflex is an automatic response that does not involve thinking. These actions are called reflexes. A reflex is an automatic response that does not involve thinking and processing Young Ji International School / College

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from the brain. A reflex such as withdrawing the hand from a hot object does not necessarily require responses from the brain .In a reflex action, the message travels from a sensory nerve to the spinal cord and from the spinal cord to a motor nerve where a specific part of the body reacts.

Reflexes help the body to respond quickly to some potentially dangerous situations and avoid further injury. Coughing, sneezing and shivering are other examples of reflex actions.

Activity A. Encircle the word that does not belong to the group and then write how the remaining items are related.

1. central nervous system, peripheral nervous system, respiratory system 2. brain, nerves, heart, spinal cord ________________________________________________________ 3. nerves, reflex, brain, blood ________________________________________________________ 4. spinal cord, cerebellum, cerebrum, brain stem ________________________________________________________ 5. axon, dendrite, cerebellum, cell body ________________________________________________________ B. Answer briefly.

1. Why is the nervous system considered the control center of the body? ____________________________________________________________________ ____________________________________________ 2. What are the parts of the nervous system? ____________________________________________________________________ ____________________________________________ 3. How do messages travel through a nerve cell? ____________________________________________________________________ ____________________________________________ 4. What are the functions of the spinal cord? ____________________________________________________________________ ____________________________________________ Young Ji International School / College

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LESSON 6: TRANSMISSION OF NERVE IMPULSES Messages from the environment travel along nerve cells as fast-moving electrical signals called impulses. An impulse begins with a stimulus. A stimulus is a part of or a change in the environment that can be detected by the receptors of the sense organs. How do these stimuli reach your brain?

The peripheral nervous system has three types of neurons that make transmission of impulses possible. These are the sensory, association and motor neurons, which work together so the body can respond properly.

Sensory neurons collect information from the receptors in the sense organs.

These send the information to specific areas in the brain via association neurons for interpretation. If action is necessary, association neurons carry these messages to the motor neurons. Motor neurons transmit messages to the muscles to activate the appropriate response.

Both the brain and the spinal cord have association nerve cells.

Association neurons in the spinal cord receive and transmit the impulses to the brain, while the neurons in the brain interpret, analyze, and create a reaction to the impulse.

When a part of the spinal cord is crushed or cut, impulses cannot travel beyond the crushed or cut point. When the area that controls signals from the legs is damaged, no sensory impulses from the legs can reach the brain.

Likewise, no motor impulses can reach the legs. Thus the legs cannot move.

Impulses travel from neuron in one direction only. It passes from the dendrite to the cell body to the axon. It cannot travel back and forth along the same nerve cell.

Neurons do not touch one another. The space between two neurons is called the synapse. How does an impulse travel through the space from one nerve cell to another if they do not touch?

When the impulse reaches the end of the axon, it causes the axon to release chemicals into the synapse. These chemicals travel across the synapse to the dendrites of the next cell. This system allows the brain to

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interpret impulses one by one preventing overloading of messages along the nerve cells.

LESSON 7; SOME AILMENTS AFFECTING THE NERVOUS SYSTEM 

Alzheimer’s disease is a brain disease characterized by gradual loss of reasoning skills and memory. Initial symptoms include memory lapses that get worse overtime. In Alzheimer’s disease, a damaged neuron suffer from plaques that cover the axon branches. These plaques are especially numerous in the frontal lobe of the brain where reasoning and memory processes occur. The greater the number of plaques, the more severe are the symptoms of Alzheimer’s disease.



Cerebral Palsy is a non-progressive disorder caused by injury to the brain during late pregnancy, birth or anytime during the first two years of a child’s life. It has a wide range of signs and symptoms involving the child’s sense of balance, his or her motor skills , and speech.



Multiple sclerosis is a disorder characterized by the destruction of the myelin sheath surrounding the axons of neurons. The myelin sheath is the structure that covers the axon. Multiple sclerosis affects different parts of the brain and the spinal cord, resulting in typically scattered symptoms like rapid involuntary movements of the eyes, problems in speech pronunciation and shaky movements of the limbs.



Cerebral thrombosis is the formation of a blood clot in a blood vessel of the brain. This may cause a stroke or a sudden loss of consciousness, followed by paralysis.

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LESSON: 8 KEEPING THE NERVOUS SYSTEM HEALTHY   

Eat foods that are rich in B vitamins. e.g are beans, peas and vegetables. B Vitamins helps enhance nervous system functioning.

Give brain workout. Engage in challenging activities like solving puzzles, reading, composing songs and producing artworks.

Take medicines only under adult supervision. Some products contain stimulants and depressants. Stimulants increase the activity of the central nervous system and make the person alert. Depressants are used to protect calmness and cause sleep. They can cause destruction of nerve cells and brain damage.

A. Write T if the statement is true. Write F if it is false.

1. Alzheimer’s disease is characterized by plaques that cover the axon branches.

2. Cerebral Palsy is caused by injury to the brain during late pregnancy, birth or anytime during the first two years of a child’s life.

3. Multiple sclerosis is characterized by the destruction of myelin sheath surrounding the axons of neurons.

4. The arrangement of neurons in the brain allows some areas in the brain to function even if one area is damaged.

5. The greater the number of plaques in the axon,the less severe the symptoms of Alzheimer’s disease.

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CHAPTER 3: ORGANIZATION IN THE ENVIRONMENT LESSON 9: LIVING AND NONLIVING THINGS Ecology is the branch of Science that deals with the relationships of living things with one another and with the environment.

-biotic components or factors are all the living things in any given environment. E.g. plants, animals, bacteria, fungi, mammals and a lot more.

-abiotic components or factors refer to the non-living things in any given environment, the physical features that interact with the environment. e.g. air, light, soil and water.

To maintain a healthy environment, all biotoc and abiotic components must interact successfully.

What are the Characteristics of living things?

The 7 Characteristics of Life: 1. Living Things are Composed of Cells: 

Single-cell organisms have everything they need to be self-sufficient.  In multi-cellular organisms, specialization increases until some cells do only certain things.

2. Living Things Have

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Different Levels of Organization:   

Both molecular and cellular organization.

Living things must be able to organize simple substances into complex ones.

Living things organize cells at several levels:    

Tissue - a group of cells that perform a common function.

Organ - a group of tissues that perform a common function.

Organ system - a group of organs that perform a common function.

Organism - any complete living thing.

3. Living Things Use Energy: 

Living things take in energy and use it for maintenance and growth.

4. Living Things Respond To Their Environment:  

Living things will make changes in response to a stimulus in their environment.

A behavior is a complex set of responses.

5. Living Things Grow:   

Cell division - the orderly formation of new cells.

Cell enlargement - the increase in size of a cell. Cells grow to a certain size and then divide.

An organism gets larger as the number of its cells increases.

6. Living Things Reproduce:  

Reproduction is not essential for the survival of individual organisms, but must occur for a species to survive.

All living things reproduce in one of the following ways:  Asexual reproduction - Producing offspring without the use of gametes.

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

Sexual reproduction - Producing offspring by the joining of sex cells.

7. Living Things Adapt To Their Environment:  

Adaptations are traits giving an organism an advantage in a certain environment.

Variation of individuals is important for a healthy species.

A. Identify the component whether it is biotic or an abiotic factor. Write B if it is biotic and A if it is abiotic. _____1. Pebble _____2. Grass _____3. Fertilizer _____4 ant _____5. Carbon dioxide _____6. Rock _____7. Mango tree _____8. Frog _____9. Sunlight

LESSON 10: POPULATIONS

Species are group of organisms that can breed with one another and produce offspring. E.g. Plants and animals.

Population refers to all the members or a species that live in the same area.

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Community is made up of several kinds of populations living together in the same environment.

As a type of species change in number, there is also a corresponding change in the physical and chemical characteristics of the area.

Ecological succession is the changes that take place in the community as time goes by.

Primary succession: takes place as organisms begin to inhibit an area that has not been occupied before e.g. A newly formed volcanic island. Firs the rocks disintegrate through weathering. Next, simple plants and other organisms provide a stable environment.

Secondary succession occurs after an existing community suffers a major disruption such as forest fire or a flash flood. First wildflowers and grasses will grow. They will be followed by shrubs and similar plants. Trees will reappear and the area will eventually become a forest again. As more complex species of plants flourish, more animal species will also take over.

A. Identify each item below whether it is a population or community. Write P for population and C for community. _____1. An ant colony _____2. A herd of cattle _____3. Bees on beehive _____4. Grasses, trees and giraffes _____5. A group of fish _____6. A flock of birds _____7. Bermuda grass and grasshoppers _____8. Sea anemones and sea cucumber _____9.coconut tree _____10. Frogs, butterflies and water lilies

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CHAPTER 5 ECOLOGICAL CYCLES LESSON 15 THE OXYGEN-CARBON DIOXIDE CYCLE The body processes that occur in most organisms require oxygen. Both humans and animals use oxygen to form the energy they need for their daily activities.

This energy-releasing process that takes place in all active cells is called cellular respiration. During the process, oxygen is used to break down carbohydrates or sugar molecules. At the end of the process, secondary products or by-products are released .In cellular respiration; water and carbon dioxide are the by-products.

The lungs excrete the carbon dioxide(CO2) making it available in the atmosphere.

Study the diagram below.

Figure5.1 Oxygen-Carbon dioxide Cycle The carbon dioxide in the atmosphere is absorbed by the plants. Plants cannot manufacture food molecules without CO2.During photosynthesis, the chlorophyll in plants react with sunlight. With the help of water and carbon dioxide, food is produced as its main product. Like cellular respiration, photosynthesis is also composed of a complicated series of steps. Its by-products are water and oxygen.

The constant movement of oxygen and carbon dioxide is called the oxygencarbon dioxide cycle. It is the continuous use and exchange of oxygen and carbon dioxide in the environment.

Another process that contributes to the carbon dioxide in the atmosphere is decomposition. When animals and plants decay, the carbon stored in their tissues is released as carbon dioxide.

Activity I. Underline the correct word or words inside the parenthesis.

1. The (nitrogen-oxygen cycle, oxygen-carbon cycle, oxygen-carbon dioxide cycle) refers to the continuous use and exchange of oxygen and carbon dioxide in the environment.

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2. Plants produce (carbon dioxide, nitrogen, oxygen) as a product of photosynthesis.

3. During the process of (photosynthesis, respiration, decomposition), plants absorb carbon dioxide and release oxygen.

4. Most organisms take oxygen from the air for (photosynthesis, respiration, decomposition).

5. Composition, Decomposition, photosynthesis) is another process through which carbon dioxide is released into the atmosphere.

6. Carbon is released as carbon dioxide when (decomposers, human beings, trees) break down plants and animals matter.

7. Most living organisms take oxygen from the air and release (nitrogen, oxygen, carbon dioxide).

LESSON 12: ECOLOGICAL RELATIONSHIPS

Ecological communities consist of interacting or potentially interacting species in the same environment. The direct interactions between species are divided into five categories. Sometimes these complex interactions and the flow of energy through the system are diagrammed in food webs, which display the movement of energy from lower to higher tropic, or feeding, levels.

Predation

Predation describes one species, the predator, feeding on and typically killing another organism, the prey species. Predators use various methods to capture prey, just as their prey uses various methods to avoid capture. Herbivory is comparable to predation, but herbivores feed on plants rather than animals. Herbivores do not necessarily kill a plant they feed on but sometimes put pressure on the plant species.

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Competition Competition describes multiple organisms fighting for the same resources.

Interspecies competition is competition between different species; intraspecies. The competition may or may not involve active interference. Squirrels and deer may both eat acorns in a site but do not directly fight for the acorns and instead make fewer acorns available for the other. Alternatively, competition may involve direct interference, like when a plant secretes chemicals from its roots to keep other plants from growing around it. The more similar two species in a community are, the more competitive they are with each other, fighting for limited resources.

Parasitism Parasitism is a relationship in which one organism (the parasite) benefits while the other (the host) is harmed. This is a positive, negative relationship. (Campbell) (Dionne L Rice Jr) The parasite usually lives on or inside the other organism.

For example, the mosquito is a parasite: it feeds on human blood, and, aside from the obvious injury, also has a chance of transferring diseases. Other examples would be ticks or fleas that live off of many large mammals. Similarly, head lice are an example of parasitism because they feed on blood from the human's head.

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Mutualism Mutualism is a relationship in which organisms benefit from each other. This is a positive/positive relationship. (Campbell) An example of this would be the relationship between a bee and a flower. The bee gets nectar and honey from the flower. The bee contributes to the flower's well-being by spreading pollen so that the flowers can reproduce. This is a required contribution to both the flower and the bee, they both rely on each other to survive. (Katarina Krizka) Another example would be when the ox pecker lands on an impalas back and eats the ticks that are a parasite to the impala. The ox pecker is benefited because it gets a meal from the tick and the impala gets benefited because the tick is no longer on it. Similarly, monkeys pick fleas from other monkeys for the same reason.

Commensalism Commensalism is a relationship in which one organism benefits from another organism that is not affected. This is a positive, neutral relationship. (Campbell) For example a small fish called the Pilot Fish follows underneath a shark and when the shark eats something the pilot fish eats the scrap pieces of the shark original kill.(Blue Planet BBC Documentary 2001).

Another example is of a birds nest in a tree. The bird is benefitting because the tree is giving the bird shelter and the tree is not getting anything in return.

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Activity: Identify the type of relationships that each situation shows.

____________1. Bangus and Tilapia feed on the same algae in a pond. ____________2. A praying mantis eats a butterfly. ____________3. Tapeworms suck nutrients from the intestinal walls of humans. ____________4. A bird picks food lodged between the teeth of a crocodile.The bird get its food and the crocodile’s teeth get cleaned. ___________5.Bernacles attaches themselves to the backs of the whales for shelter and transportation. The whales are not affected. ___________6.Epipyhtes grow on the branches of trees where they receive light.

They take no nourishment from the trees. ___________7. Fungi cause athletes foot on the skin of humans. ___________8. Sheep and cows eat the same kind of grass in the field. ___________9. A lion eats an antelope. ___________10. A sea anemone provides a shelter for a clown fish .The clownfish attracts a smaller fish to come closer to the sea anemone.

The sea anemone then captures the fish and eats it.

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LESSON 16: THE FOOD NUTRIENT CYCLE Food contains nutrients that are necessary for the survival of an organism.

Nutrients travel in a cycle among organisms in the food web. The Process by which nutrients continuously pass from living things to nonliving things and back to living things is called the food nutrient cycle.

The illustration above shows the transfer of nutrients among organisms and the soil. When living things die and decompose, they enrich the soil with nutrients.

Plants use these nutrients, along with water, carbon dioxide and sunlight to make food. When consumers eat the plants, the food nutrients move from plants to animals.

These nutrients are passed on to the next links in the food chain or food web. When the plants and animals die, decomposers break them down. Bacteria, fungi and small animals like worms are examples of decomposers. The products of decomposition mix with the soil and make it fertile.

Activity I A. Write true if the sentence is correct. If not, change the underlined word or words to make the statement true. Write the changes on the blanks. ______1.The process by which nutrients continuously passes from living things to non-living things and back to living things is called food nutrient cycle. ______2. Animals produce food through photosynthesis. ______3. When decomposers feed on dead plants and animals, nutrients are returned to the soil.

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______4.Plants use nutrients, water, carbon dioxide and sunlight to make decomposers. _____5. Food contains gases necessary for the survival of an organism. _____6. The decayed matter mixes with the soil and makes it fertile. _____7. The nutrients in the soil make plants healthy. _____8.Bacteria, fungi, and worms are producers.

UNIT 3: MATTER , ENERGY AND MOTION LESSON 20: MATTER AND ITS COMPOSITION Matter is anything that occupies space and has mass.

Consider the table of your living room and the books on the shelves. The table occupies the center of the living room. The book also take up space on the shelves. You can measure the quantity of matter they contain by obtaining their mass.

Mass is the amount of matter in an object. Mass is often expressed in terms in grams or kilograms.

Matter is made up of very tiny particles called atoms. An atom is so tiny that no person has ever actually seen one. Although it is very small it contains smaller parts. The nucleus of an atom is at the center. It contains protons and neutrons. A proton has a positive electric charge while a neutron has no charge at all. Moving around the nucleus are small-negatively charged particles called electrons.

An atom is identified by its atomic number. The atomic number is the number of protons in the nucleus of an atom. For example, the element oxygen has 8 protons and so the atomic number of oxygen is 8.For a neutral atom, the number of protons is equal to the number of electrons. An atom can also be described by its atomic mass.

The atomic mass is the number of protons and neutrons in the nucleus of an atom.

Uranium has 92 protons and 46 neutrons. Its atomic mass is 138.Substances that contain only one kind of atoms are called elements. Scientists have discovered over one hundred kind of elements. Some elements occur naturally. Others can be prepared in laboratories.

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Figure 7.1 an oxygen atom

Activity Identify what is being described in each statement. Choose from the terms below.

Atom

Atomic mass

Atomic number

electron

neutron

nucleus

mass

matter proton

___________1. Anything that occupies space and has mass. ___________2. The smallest particle of matter ___________3. A positively charged particle of an atom ___________4. A negatively charged particle of an atom ___________5. The central part of an atom ___________6. The number of protons in the nucleus ___________7. The sum of protons and neutrons ___________8. The total amount of substance in matter ___________9. A particle that has no charge

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LESSON 21: CLASSIFICATION OF MATTER Targets: -Classify matter -Differentiate the types of Matter -Give examples for each type of matter

When two or more type of atoms are joined together, they form larger particles called molecules. Molecules can be further classified into different classes based on their composition, properties and behavior. To understand clearly the classification of matter, study the concept map below.

Matter can be divided into general types-pure substances and mixtures.

Pure Substances A pure substance is a type of matter with definite, fixed composition and with uniform properties throughout. Gold, aluminum and water are all pure substances.

Pure substances are further divided into elements and compounds. Elements are made up of the same type of atom. These are substances that cannot be broken down into simpler substances by ordinary chemical means. Elements are represented by symbols. Copper(CU),Sodium(Na)hydrogen(H),Chlorine(Cl), and Oxygen (O) are some of the familiar elements. There are more than one hundred identified elements.

Some substances are made up of more than one type of atom. A compound is a type of pure substance that is made up of two or more type of elements. It has a defined chemical structure.

Water is an example of a compound. It is made up of hydrogen (H) and oxygen (O) atoms in a ratio of 2:1.This means that two atoms of hydrogen and one atom of oxygen combine to make one molecule of water. The Chemical symbol for water is H2O.

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Mixtures When you combine powdered milk and water, you will form liquid milk, which is a mixture. A mixture is a combination of two or more substances in varying proportions. pure substance

pure substance

mixture

Figure 7.3. A mixture is a combination of two or more different substances.

Mixture may either be homogeneous or heterogeneous. In a homogeneous mixture, the components form a uniform phase. One substance cannot be distinguished from another. Air, seawater, milk and coffee are homogeneous mixtures. Solutions like seawater and coffee are considered homogeneous because they appear as one phase. Each region of a sample is identical with all other regions of the sample.

In a heterogeneous mixture, the individual substance can be easily distinguished.

Vegetable soup, halo-halo, gravel and sand, gelatin and cooked starch are examples of heterogeneous mixtures. These mixtures are made up of more than one phase of matter or of different parts and can be separated physically.

(a) (b) Figure 7.4. Kinds of mixtures (a) homogeneous mixtures; (b) heterogeneous mixtures

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Activity Classify each material or substance as mixture, element, or compound. Put a check in the appropriate column.

Material/Substance 1.phosphorous 2.soil 3.fruit salad 4.sugar 5.cup of coffee 6.chlorine 7.water 1. hydrochloric acid 9.silver 10.carbon dioxide

Element

Compound

Mixture

A. Listed below are pairs of different classes of matter. How would you differentiate the first type from the second type in each pair?

1. pure substances and mixture _____________________________________________________________ ____________________________________________.

2. Compound and element _____________________________________________________________ ____________________________________________.

3. homogeneous mixture and heterogeneous mixture _____________________________________________________________ ____________________________________________.

Go Beyond The elements of a certain group are unable to combine with any other element under normal conditions. They are known as the noble gases. They are found in the farthest side of the periodic table. The elements in this group are helium (He), Neon(Ne), Argon(Ar) , krypton(Kr), xenon (Xe) and radon(Rn). Only under controlled conditions in the laboratory can these elements combine with other elements to form compounds.

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LESSON 22: CHANGES IN MATTER Targets -Describe the types of changes that matter undergoes -Give examples for each type of change Matter can undergo either a physical or a chemical change. A physical change occurs when a substance changes in appearance without undergoing a change in composition. A physical change can happen if you cut, grind, bend, break, split, crack, or crush a material. A change in temperature can also cause a physical change. The transformation of water to ice at 0°C and from water to steam at 100°C is a physical change.

The process of changing from one physical state to another is known as phase change. Ice is a solid. It can change to water, which is a liquid. Water can change to water vapor, which is a gas. The composition remains the same. It is still made up of water molecules containing two hydrogen atoms and one oxygen atom per molecule.

Figure 7.5. Melting of ice is an example of a physical change.

Have you seen tarnished bronze statues undergoing discoloration?

Do you know why iron window grills are becoming rustier? These things undergo chemical changes.

A chemical change occurs through a chemical reaction. It happens when one substance is transformed into another substance with a totally different composition and set of properties. A chemical change is always accompanied by the formation of a new substance.

(a.) (b.)

Figure 7.6. (a). When charcoal burns, the carbon in the charcoal combines with oxygen in the air to produce carbon dioxide.(b) When iron steel rusts, iron combines with oxygen to form ferric oxide, the chemical name for rust.

In any chemical reaction, the substance that you start with are called reactants.

The new substance formed by the reaction are the products. When charcoal burns, carbon and oxygen are the reactants. Carbon dioxide is the product. When iron rusts, iron and oxygen are the reactants. Iron oxide or ferric oxide is the product.

Carbon+ oxygen Iron + oxygen

heat

carbon dioxide + (light and thermal energy) iron oxide or ferric oxide (rust)

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The words heat and water in the equations above meant hat heat and water are necessary for the reactions to happen. The first equation may be read as follows: In the presence of heat, carbon and oxygen produce carbon dioxide. Light and thermal energy are given off.’’ The product of a chemical change like this cannot be brought back to its original form by ordinary means.

Chemical changes occur when something burns, rusts, decomposes, ferments or undergoes other chemical reactions.

Activity A. Write PC if a physical change occurs and CC if a chemical change takes place in the following processes. _____1. Formation of clouds _____2. Corrosion of iron _____3. Tanning of leather eggs _____4. Melting of sugar _____5. Burning of plastic

_____6. Making ice candy _____7. Ripening of papaya _____8. Cooking hard-boiled _____9. Spoiling of milk _____10. Carving wooden figure

B. Answer briefly 1. How does a physical change differ from a chemical change? ____________________________________________________________ ______________________________________________________.

2. Why a change of state is considered a physical change? ____________________________________________________________ __________________________________________________________.

Go beyond Suppose you were given some sugar cubes, water a, a grinder, a pan and a hot plate. What physical and chemical changes could you make in the sugar? Explain each.

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LESSON 23: MATERIALS IN THE HOME

Targets: Identify commonly use materials in the home Categorize materials in the home according to their uses

Do you notice that there are many materials found in your home? You may call these things household materials. Some of them may be in solid form. Others may be in liquid or gaseous form. You use them to do work like preparing food and cleaning the house.

Antiseptics You groom yourself by bathing and brushing your teeth. You need materials like bath soap, shampoo and toothpaste. Before you eat, you wash your hands with soap and water or you use a sanitizer or alcohol. You rinse your mouth with mouthwash to prevent bad breath and gum disease.

Soap, toothpaste, sanitizer, alcohol, shampoo and mouthwash make your body clean and protect you from infection. These materials contain antiseptics.

Antiseptics are substances that reduce the growth of harmful microorganisms.

Figure 7.7. Antiseptics prevent infection.

Disinfectants Disinfectants are strong chemicals that eliminate infection-causing microorganisms.

Most are acids. They are used to clean bathrooms, toilets and kitchens. Toilet bowl cleaner, muriatic acid and chlorine are examples of disinfectants. Disinfectants are not intended to come in contact with human skin. These are only used on surfaces, tools or utensils.

Fig. 7.8. Disinfectants eliminate infection-causing microorganisms.

Additives Different materials are used in cooking. Salt, sugar, black pepper and soy sauce are examples of additives. These are added to food to enhance or improve its flavor.

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Monosodium glutamate (MSG) or vetsin is a chemical additive popularly used in cooking. However, some people prefer table salt and herbs since these are natural ingredients.

Fig. 7.9. Additives are used to enhance the flavor of food.

Preservatives Preservatives are substances that are used to prevent food spoilage. These prevent the growth and action of bacteria and molds, which cause food to spoil.

Salt and vinegar are the most commonly used preservatives. Chemicals like sodium nitrate and sodium benzoate are also preservatives.

Figure. 7.10 Preservatives prevent food spoilage

Insecticides and Pesticides Insecticides and pesticides are used to kill insects and other pests. These are used in houses infested with cockroaches, rodents, mosquitoes, termites and ants.

Figure 7.11. Insecticides and pesticides

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Flammable Materials

Some materials are readily flammable and pose fire hazards. These materials include LPG, kerosene, gasoline, alcohol, matches and candles. They are used as fuel or as lighting materials.

Paints are substances that form a dry coat when spread over a surface. They are used to prevent rusting and to beautify homes and furniture. Paints are also highly flammable.

Fig. 7.12. Flammable materials

Plastics Plastics are synthetic materials that are durable or long-lasting. They are mostly heat and water resistant. A lot of materials in the home are made from plastic.

Fig. 7.13. Containers made from plastic.

Go Beyond Among the most common food additives are the nitrates. They help preserve meat so it stays fresh longer. But now there is scientific evidence that when meat is cooked, the nitrates present are converted into nitrosamines, which have been shown to cause stomach cancer in humans.

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LESSON 24: TECHNOLOGY IMPROVES MATERIALS Targets Define technology Describe how technology improves materials Infer how technology helps society Telephones and cell phones make communication easier. But between these two, which is more convenient to use? In doing your assignments and reports, which is easier to use, a typewriter or a computer?

Cell phones and computers are two important products of technology.

Both bring about convenience and comfort to the users. Technology is the practical application of science. Scientific principles and skills are utilized in the production of new materials and in improving existing ones. Technology applies not only to gadgets and appliances but also to household products that you use every day.

Can you name other products of technology?

Activity A. Between each pair of items, which one is the improved product? Encircle that item.

1.

Activity 2 Answer briefly 1. What is technology? _____________________________________________________________ ________________________________________.

2. How does technology change our way of living?

___________________________________________________ ___________________________________________________ ____.

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LESSON 25: PRODUCT LABELS -Describe a product label and identify its parts -Identify the symbols on product labels -Infer the importance of product labels Materials can be easily recognized by looking at product labels. A product label provides information about the product. It tells you the product’s ingredients or the substances it contains.

Labels provide precautions and warnings on the use of the products.

These inform the users or consumers on the use of the products. These inform the users or consumers on how to use a particular product properly.

Thus, it is important to read the label before using any product.

Fig.7.14 Parts of product label Instructions on how to store a product is also found on the label. Some products must be kept out of the reach of children. Others should be kept in a cold, dry place. There are also products that must be kept out of direct light.

Warning signs indicate if a product is safe or potentially dangerous. A skull and crossbones label means it is poisonous. A flame symbol means it is flammable. The expiry date, production date, and batch number are also included in the product labels for the user’s reference.

Fig. 7.15. Warning symbols commonly found on household materials

Activity A. Identify the parts of a product label.

B. Answer briefly.

1. What is a product label? ________________________________________________________ _________________________________.

2. What are the parts of a product label? ________________________________________________________ _________________________________________.

3. Why should everyone read the label beforeusing any product? ________________________________________________________ ________________________________________.

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Go Beyond When we read nutrition label and see ‘’0 g‘’ (zero gram) of a particular ingredient such as transfat, we expect to be eating none of that ingredient. However, manufacturers can list an item as having 0 g per serving if the food contains less than 0.5 g. This can become a problem since most individuals consume more than one serving.

LESSON 26: SAFETY PRECAUTIONS IN USING AND STORING MATERIALS TARGET Explain safety precautions in the use and storage of materials

Some materials are dangerous and accidents can happen if these are not handled properly. Thus, it is important to store and use these materials properly.

The proper storage and use of materials in your home can keep you safe from accidents.

Here are some tips: 1. Classify materials according to their use. Have a specific storage place for each kind of material.

2. Put labels on containers to indicate their contents. This will prevent you from using the wrong materials for specific purposes.

3. Put flammable chemicals like kerosene, paint thinner paint and gasoline in tightly sealed containers. These should be kept in well-ventilated places away from sources of heat.

4. Flammable materials, poisonous substances, and pointed tools should be kept out of children’s reach.

5. Food and materials for food preparation should be kept in tightly closed containers and stored separately from cleaning materials. Keep them in a dry place to avoid bacterial contamination. Moisture creates an ideal environment for bacterial growth.

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Activity A. Classify the household materials in the list below as to where they should be found. Write each item under the correct heading in the table that follows. microwave powdered juice gas stove vinegar lawn mower soap shovel Kitchen

forks knife pillows soy sauce hammer facial wash blender Bedroom

can opener cleanser alarm clock rope shampoo hair conditioner pans Bathroom

Garage/Storeroom

B. Answer briefly.

1. Why should materials and chemicals be properly used and stored? ___________________________________________________________ ________________________________________.

2. What precautions should you follow when using and storing materials at home? ___________________________________________________________ ______________________________________________.

Go Beyond Polymerization is the process in which single molecules of a substance are joined chemically to form long chains called polymers. One polymer that has Young Ji International School / College

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had a great effect on modern life is polystyrene. Because of polystyrene, we have numerous disposable plastic items in our shelves, from plastic grocery bags to jewel cases for CDs. Because of its positive characteristics, polystyrene is used extensively.

However, the edges of highways and our landfills reflect its widespread use by a growing population. Foamed plastic, as it currently exists, is not biodegradable within a reasonable amount of time. How can the problems created by mass disposal of items made from polystyrene be avoided? Is there a way to make a biodegradable plastic bag, CD case, toy, or toothbrush? This is one of the challenges science and technology face today.

LESSON 27: PROPER WASTE DISPOSAL

Targets Describe the effects of improper waste disposal Describe the types of wastes and determine how to dispose of them properly

What do you do with your empty plastic bottles and other wastes? Do you dispose them properly?

Technology makes life easier and more comfortable. However, more new products can also mean more problems. One of these is the production of wastes.

When wastes are not properly disposed of, serious problems may arise.

Wastes can block canals and drainage systems and cause flooding. They can contaminate water pipes and cause diseases due to contaminated water.

Solid wastes that are dumped on landfills can also take up so much space.

Moreover, the smell of decaying matter attracts disease-causing pests.

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Since millions of people use products every day, wastes accumulate everywhere. The next question is, ‘’ What can we do to manage wastes properly?

Here are some useful suggestions: 1. Separate biodegradable wastes from non-biodegradable wastes.

Biodegradable wastes like vegetable and fruit leftovers and garden leaves can be reduced into finer particles and made into compost. These can be buried in pots with soil or in ground pits, following the correct steps of composting. After several weeks, the compost may be used as fertilizer.

Non-biodegradable wastes such as cans, metals, glass, bottles, plastics, Styrofoam, rubber and leather should not be thrown in bodies of water because they contaminate the water, kill marine animals and plants, or clog waterways such as canals and drainage pipes.

2. Sort and label non-biodegradable materials. Containers such as plastic bags, cartons, tin cans, and glass bottles can be cleaned and reused or recycled.

To reuse is to use the same material for its original purpose. Reuse materials like glass, plastic or metal containers for storage or wrapping purposes. Empty tetra packs or used plastic cups can be used as seedling pots. If you reuse one thing several times, you will generate less waste.

To recycle means to use the material again in another way or for another purpose. Old clothes, paper, boxes, glass bottles and plastic containers are some materials that can be recycled.

Fig. 7. 16. Samples of recycled paper and plastic materials 3. Before throwing acids, expired medicines, and broken glass wrapped them in labelled plastic bags.

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Activity A. Write True if the sentence is correct. If not, write False. _______1. Biodegradable wastes can be placed in a compost pit. _______2. Plastics can be placed in a compost pit. _______3. Tin cans and glass bottles can decompose. _______4. To reduce means to us the material again in another way or for another purpose. _______5. To reuse is to use the same material for its original purpose. _______6. After several weeks, non-biodegradable wastes will turn into fertilizer.

B. Answer briefly.

1. Why is recycling a good practice? ___________________________________________________________ ________________________________________

2. What are some good practices in handling biodegradable wastes? ___________________________________________________________ ________________________________________.

3. How do terms reuse and recycle differ? ________________________________________________________________ _________________________________________.

Go Beyond Have you ever worn a shirt made out of corn resin? Since 1980s manufacturing processes for turning corn starch and corn fibers into useful products have become a reality. Corn-based packing materials have been developed. Molded bottles are being manufactured for use in short-term shelf products such as milk.

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The hope is that these products will help conserve fossil fuels, be quickly biodegradable, and therefore more environment- friendly. Markets for cornbased polymers are similar to those for petroleum-based polystyrene products like leaf and lawn bags, food packaging and textile. Research is on going with regard to how well microorganisms break down the materials.

CHAPTER 8: ENERGY Anything that has the capacity to change or move has energy. Energy enables us to do things. You can study, work and play because of the energy that comes from the food you eat. Vehicles move because of the energy from gasoline.

In Science, work can be defined as the transfer of energy from one material to another in order to cause a change in the latter. Therefore, energy is the capacity to do work.

In this chapter , you will learn about the different forms of energy and how they are changed and used in the environment.

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LESSON 28: FORMS OF ENERGY

TARGETS -Identify the different forms of energy -Describe each form of energy Energy comes in many forms. Some of these forms are chemical, mechanical, electrical, light radiant, thermal, sound and nuclear energy.

Chemical Energy Chemical energy is the energy stored in a substance due to the bonding of atoms.

Once the bonds are broken, energy is released or changed. All kinds of matter contain chemical energy because they are composed of atoms that are bonded together. Wood, food, batteries, gasoline, paper and leaves are examples of matter that contain potential chemical energy.

Mechanical Energy Mechanical energy is associated with objects in motion. Anything that moves has mechanical energy. A running dog, a flying bird, a rolling stone, a speeding car, a jumping dog, and flowing water all possess mechanical energy.

Electrical Energy Electrical Energy results from the movements of electrons along conductors.

Electricity is created in power plants and is transmitted to different locations through transmission lines. Electrical energy is essential in our lives. Without it, we will have difficulty doing a lot of activities.

Radiant Energy Radiant energy or radiation is a form of energy that can travel through the empty space. Radiant energy from the sun travels through space in all directions in the Young Ji International School / College

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form of waves or rays called electromagnetic waves. We receive radiant in the form of sunlight.

Radiant energy can be converted to other forms of energy by using solar panels.

The energy collected during daytime can be stored and used during night-time.

Fig. 8.1 harnessing solar energy

Light Energy Light Energy is a form of radiant energy. It comes from luminous objects like the sun, a lamp or a lighted candle. We can see the things around us because of light energy. Plants are able to make food with the help of light energy.

Thermal Energy Rub your palms together briskly for a few seconds. Your hands will feel warm because heat is produced. Thermal or heat energy is created mainly by the friction of moving molecules. When atoms and molecules in a substance vibrate, move or bump against one another rapidly, thermal energy is produced. The greater the movement of the molecules, the greater the amount of heat generated.

All forms of energy generate heat energy. An electric fan that has been turning for quite some time normally becomes warm.

Sound Energy Vibrating objects produce sound energy. When the string of a guitar is plucked, it vibrates and produces waves that interact with air molecules. This action produces sound. Sound travels through a medium and can pass through solids, liquids or gases. But it travels best in solids because the molecules of solids are more compact and compressed compared to the molecules of liquids and gases.

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Nuclear Energy Nuclear Energy is produced when the atoms of a certain elements, like uranium split or when several nuclei of lighter atoms, like hydrogen combine. Nuclear energy may be produced through two processes: fission and fusion Nuclear fission occurs when an atom breaks into pieces. A heavy atom splits when it is heat with a neutron. This sets off a chain reaction and releases vast amounts of energy.

Nuclear fusion occurs when the nuclei of atoms join or fuse together to form helium and release nuclear energy.

Activity A. Identify the form or forms of energy represented in the pictures below.

1. flag raising at school 2. boiling water

2. girl playing violin

4. plugged rice cooker

3. watching tv at home

6. land view

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LESSON 29: ENERGY TRANSFORMATION

Targets Discuss energy transformation Give examples of energy transformation Explain the law of conservation of energy

Why do you think the girl has to eat breakfast before going to school? What would happen if she didn’t take her meal in the morning?

We need energy to do our daily activities. When we eat food becomes the fuel that enables us to do our tasks. Machines can only function with the use of energy.

Electricity or gasoline and other kinds of fuel are used to operate machines.

What you have just read are examples of energy changing from one form to another. This idea is known as transformation of energy. The chemical energy in food is transformed into mechanical energy when we perform our daily activities.

Electrical energy or the chemical ë‘‘of fuel is transformed to mechanical energy in the operation of machines. Does the amount of energy change when it transforms?

During energy transformation, the quantity of energy does not change. This is summarized in the law known as the law of energy conservation. It states that energy cannot be created nor destroyed but may be changed from one form to another. The total amount of energy remains constant or the same.

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A. Give one transformation of energy that may occur in the appliances devices shown below. The first one is done for you.

washing machine 1. from electrical to mechanical

2. egg cooked

boy dancing 2. __________________

3. open flashlight o

3. Door and doorbell 4. lamppost solar panels B. Answer briefly 1. What is energy transformation? ___________________________________________________________________ ____________________________________.

3. Why is energy transformation important? _____________________________________________________________ _________________________________________.

4. What is the law of conservation of energy? _____________________________________________________________ __________________________________________.

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Go Beyond Do you know how electricity may be produced? Electricity may be generated through hydroelectric power plants.

In hydroelectric power plants, the potential energy of water is converted into mechanical energy when it falls down with great pressure and turns turbines. As turbines spin, the generator converts the mechanical into electrical energy thus supplying electricity to power lines.

Botocan Hyroelectric Power Plant

LESSON 30: HEAT TRANSFER -Explain heat as a form of energy -Describe how heat transfers from one object or location to another -Identify the types of heat transfer that occur among objects or in the environment We have learned that energy is neither created nor destroyed, but only changes in form. Suppose your hands feel cold during camping. What would you feel if you briskly rubbed your palms together?

Heat results from the movement or vibration of particles or molecules of matter. Heat is produced whenever there is energy transformation. Heat travels or flows by conduction, convection, or radiation.

Conduction is the primary method of heat transfer that occurs in solids.

It requires direct contact with the source of heat. Heat energy passes from molecule to molecule. Heat moves from the hotter to the cooler part of a solid.

When heat moves in liquids or gases, convection currents are formed.

As the liquid or gas heats up, it expands become lighter, and rises. The cooler liquid or gas descends to replace it. This method of heat transfer is called convection.

What method of heat transfer is shown in the picture on the right? The heat from the sun travels and reaches the earth’s surface through electromagnetic waves. When these waves radiate and come in contact with Young Ji International School / College

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an object the waves transfer heat to that object. The sun warms the earth through radiation.

Activity A. Write True if the statement is correct. If it is False, change the underlined word or words to make the statement correct. ________1. Convection is the transfer of heat energy by the movement of liquid or gas. ________2. Conduction is the transfer of heat through a vacuum ________3. Conduction is the transfer of heat that requires direct contact of materials. ________4. In the transformation of energy, heat is never produced. ________5. Convection is the transfer of heat through a space or vacuum. _______6. Heat is described as a s form of energy that is produced due to the movement or vibration of the particles or molecules in matter. _______7. Heat moves from a cooler object to a hotter object.

B. 1. What is heat? ________________________________________________________ _________________________________________.

3. How is heat produced? _________________________________________________________ ________________________________________.

4. What are methods of heat transfer?Explain each. _________________________________________________________ _________________________________________ Young Ji International School / College

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CHAPTER 9: MOTION Motion occurs all around us .You can see people walking, cars travelling along the highway, and tress swaying to the wind. Do you ever wonder what makes things move? Or what causes an object to change its speed or direction?

Motion involves a change in position. Scientists have discovered different laws that explain motion.

LESSON 31: SPEED AND VELOCITY

Targets -Define the terms speed and velocity -Explain the difference between speed and velocity -Calculate the speed and velocity of a moving object If you were asked to describe the speed of a moving vehicle you would probably say that it is fast, very fast, slow or very slow. What does speed mean?

Speed tells how fast an object is moving from one place to another. It can be measured by dividing the distance travelled over the time interval. Thus, s= d t where s is the speed, d is the distance, andt is the time it has taken an object to cover the distance.

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Example 9.1 A car covers a distance of 300 m in 25 seconds. What is its speed?

Solution: Given: d= 300 m t= 25 s Find: s s= d t s=300 m=12 m/s 25 s Velocity is the speed of an object in a particular direction. Consider this example. During the first trip of a bus, its velocity was 52 km/h east. On the return trip, its velocity was 52 km/h west. Notice that the speed of the bus remained the same, but the direction of motion was different. Thus, the bus took two different velocities.

A. Solve the following problems: 1. Calculates the average speed of a cheetah that runs 140 meters in 5 seconds.

2. Cedrick ruins to get his ball. If Cedrick runs a distance of 7.5 meters in 4 seconds. What is his speed?

3. A car starts travelling northward at 1:30 pm and reaches the car destination at 4: 30 pm. What is its velocity if its displacement is 180km?

4. On the average, it takes your father 15 minutes to drive his car from his office to your school to fetch you. Your school is about 12 km from his office. What is the average speed of your father’s car?

B. Answer briefly: Young Ji International School / College

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1. What is speed? ___________________________________________________________ _________________________________________.

2. How do you determine the speed of an object? ___________________________________________________________ ________________________________________.

3. What is the difference between speed and velocity? ___________________________________________________________ ___________________________________.

4. One airplane travels due north at 350 km/h, while another travels due south at 350 km/h Are their speeds the same? Are their velocities the same? Explain.

LESSON 32: ACCELERATION Targets Define acceleration Cite some factors that affect the acceleration of an object Compute for the acceleration of a moving object

Imagine you are in a car waiting for the stoplight to turn green. The light turns green, the driver steps on the accelerator and the car speeds up. As the car moves faster, you feel the change in motion as your body is pushed backed against the seat. The vehicle either speeds up or slows down until you reach your destination.

You can say that the car’s velocity changes. How do you determine the rate of change in velocity of a moving object?

Activity A. Solve the problems. In each case, assume a constant change in speed or velocity.

1. A car runs at a speed of 58 km/hr. Its speed increase to 89 km/h after 12 seconds. What is the car’s acceleration?

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2. A participant ran in a 500-meter dash race. He was initially at rest. After 8 seconds, he overtook the other participants and reached a final velocity of 7 m/s. What was the acceleration of the participant?

3. A delivery truck travelling 60 km/h hits the brakes and comes to rest in 6 seconds. Find its acceleration.

4. A ball moves at a speed of 15 m/s. It suddenly stops after 5 seconds. What is its acceleration?

B. Answer briefly.

1. What is acceleration? ____________________________________________________________ _________________________________________.

2. How do you calculate the acceleration of an object? ____________________________________________________________ __________________________________________.

3. How does acceleration differ from deceleration?

Go Beyond Seat belts, car seats and air bags are three inventions that have been developed to protect people in vehicles from hazards related to velocity and acceleration. Many countries have laws acquiring the use of seat belts and infant car seats. It is responsible to mandate the use of this equipment?

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LESSON 33: FIRST LAW OF MOTION: INERTIA

Targets -Explain the first law of motion -Observe the first law of motion at work in a simple experiment

What makes motion possible? A flower vase changed its position if a person applied a force to lift it. There can be no motion when force is not applied.

Observe the piles of books on your table or the bottles and cans in your kitchen.

These objects remain in their places unless something or someone acts upon them. Remember that a push or a pull applied on an object is called force.

Therefore, force causes an object to move.

Sir Isaac Newton is an English physicist who formulated a number of laws explaining the nature of motion. One of these is the first law of motion, which is also known as the law of inertia.

The first law of motion explains that an object continues in a state of rest or in a state of motion at a constant velocity unless an external force acts on it. Why this is called the law of Inertia? What is Inertia? Inertia is the tendency of any object to resist changes in its motion

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Activity A. Choose the correct word from the terms given to complete each sentence.

Write your answer in the blank.

Motion Newton force rest Inertia

Sir Isaac (1) _____________ was the first to use the concept of force and mass in describing the (2) _______________ of objects. Newton’s first law of motion states that an object at (3) ______________ will remain at rest and an object in motion will remain unless it is acted upon by an external (4) ______________, .This is also called the law of (5) _______________.

B. Answer briefly 1. How does the law of inertia explain why passengers in a bus move forward when a bus suddenly stops? ___________________________________________________________ __________________________________________.

2. How do you overcome the inertia of an object? ___________________________________________________________ __________________________________________

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LESSON 34: SECOND LAW OF MOTION: ACCELERATION Targets - Explain the second law of motion -Define force -Show the relationship between force, mass and acceleration

Get ten identical books. Make two piles of books on the table. Place two books in one pile and eight books in another pile. Push both piles at the same time. Which pile is more difficult to push?

Newton’s second law of motion states that when a force acts on an object, the object will accelerate in the direction of the force. The greater the mass of the object, the greater is the force necessary to accelerate it. The relationship between force, mass and acceleration is expressed mathematically in the equation: F= ma Where: F= force in kgm/s² or Newton (N) m= mass in kg a= acceleration in m/s² Consider the boys in the picture below. One is pushing a 15-kg load while the other a 10-kg load. Which boy do you think needs to exert more force for the hand trolley to move forward? Newton’s second law of motion tells us that the more massive load requires a greater amount of force.

Boy pushing a hand trolley If each load accelerates by 2 m/s², the force required for each would be: F= ma = 15 kg x 2 m/s² = 30 N

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F= ma = 10 kg x 2 m/s² = 20 N

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Activity A. Two similar cars are travelling on the highway. One car has only one passenger, while the other has five passengers. If both have the same gasoline consumption, whish of the following statements would be correct?

Explain your answer.

1. The heavier car accelerates more than the lighter car.

2. The lighter car accelerates more than the heavier car.

3. The cars have the same acceleration. ________________________________________________________ ________________________________________________________ ________________________________________________________ ____________________________

B. Answer briefly.

1. What is the second law of motion? ___________________________________________________________ _______________________________________.

2. How does the mass of an object affect its acceleration if a constant force is applied on it? ________________________________________________________________ __________________________________________.

3. How does force affect the acceleration of an object with a given mass? ___________________________________________________________ __________________________________________.

Go Beyond On Earth, an object with a 100 kg mass experiences a gravitational force of about 980 N. The moon’s gravity is about one sixth the gravity on Earth. An object with a 100-kg mass experiences a gravitational force of only about 160 N on the moon.

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LESSON 35: THIRD LAW OF MOTION: ACTION AND REACTION Targets Discuss the third law of motion Identify action and reaction Newton’s third law of motion states that for every action, there is an equal and opposite reaction. Whenever two objects interact, they exert forces upon each other. These are called action and reaction forces. For every action exerted by an object, there is a force that is equal in amount, but in the opposite direction that the object exerted on applies. There are two separate forces and two objects involved. Observe the example below.

When you walk, the action force comes from your feet pushing against the floor. You weight is balanced by the reaction force from the floor. The floor pushes up against your feet. The reaction force is what you feel in your feet. You do not move upward because the action and reaction forces are equal.

What happens when two forces are equal but come from opposite directions? If the forces acting on an object are balanced, the object will remain in its state. But if one is greater than the other, the object will move in the direction of the greater applied force.\

Activity A. Answer briefly.

1. What is the third law of motion? _____________________________________________________________ _________________________________________.

2. A boy riding a skateboard pushed hard against a wall. What do you think happens? _____________________________________________________________ _________________________________________

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B. Draw the direction of the forces in each figure. Use arrows and label them as action force(AF) and Reaction force(RF).

1. boys tug of war

2. boy catching a ball

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2. a gift in a table

4. boy pushing an object

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