Junior Cycle Success - Science - Website Sample

Michael Kavanagh

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Steps to Success

Topic 1 | What is Science ? 03

Topic 2 | The Origin of the Universe 09

Topic 3 | The Solar System 13

Topic 4 | Space Exploration 19

Topic 5 | Earth, Moon, and Sun 23

Topic 6 | Cycles in Nature 29

Topic 7 | Climate Change 33

Topic 8 | Energy Sources and Needs 37

Topic 9 | Matter 41

Topic 10 | Atomic Structure 45

Topic 11 | Classifying Substances 49

Topic 12 | Forming Compounds 53

Topic 13 | Properties of Materials 57

Topic 14 | Acids and Bases 61

Topic 15 | Exothermic and Endothermic Reactions 65

Topic 16 | Rates of Chemical Reactions 69

Topic 17 | Sustainability 75

Topic 18 | Measurement and Density 79

Topic 19 | Force and Motion 85

Topic 20 | Patterns and Relationships 91

Topic 21 | Applications of Physics 95

Topic 22 | Electricity and Electronics 99

Topic 23 | Energy 105

Topic 24 | Electricity Generation 109

Topic 25 | Cells 115

Topic 26 | Inheritance and Evolution 119

Topic 27 | Human Reproduction 123

Topic 28 | Digestion, Circulation, and Breathing 129

Topic 29 | Health 137

Topic 30 | Ecology 143

Topic 31 | Photosynthesis and Respiration 147

Scan the QR code on the back of the cover to get access to our bank of online resources to further assist you in your exam preparation.

Michael has been teaching Science and Biology at St Augustine’s College, Dungarvan since 1992. He is the current chairperson for the Waterford branch of the Irish Science Teachers Association. Through his involvement with the ISTA, he has arranged various online webinars to support teachers in the different strands of the Science specification. He has produced a bank of resources and workbooks online for both Biology and Science. He has acted as an associate with the JCT Science team and has assisted in the delivery of in-service for teachers on the new Junior Cycle Specification. He is currently an associate with the senior cycle Biology team with the PDST.

Michael Kavanagh

Meet the author

1.1 How Scientists Work

Scientists ask questions about the world around them and carry out research to learn more about the problems they are trying to solve. Scientists try to predict what will happen in different situations. A hypothesis is a temporary explanation based on observation that can be tested. Hypotheses are used to predict what will happen in different situations.

Scientists carry out experiments to see whether their hypothesis is supported or not. During the experiment, scientists collect data by recording measurements and observations. It is often necessary to repeat an experiment many times to be certain the data collected is reliable. When the experiment is over, scientists must analyse the data and decide whether their hypothesis is supported or not. This can lead to the scientist modifying the hypothesis and designing a new experiment, which may eventually lead to the discovery of new knowledge.

1.2 Scientific Experiments

The scientific experiment begins with a question. A scientist might ask the following: Does adding fertiliser make a plant grow bigger ? She might then carry out some research, finding out that plants need many types of minerals to grow, such as nitrogen found in fertiliser. The scientist can then develop a hypothesis that can be tested by experimenting.

Hypothesis:

To test the hypothesis above, she will begin by adding different concentrations of fertiliser to similar-sized tomato seedlings and then measure the maximum height each plant reaches after the same period. In this example, the concentration of fertiliser is intentionally changed and is known as the independent variable . The height of the seedlings is measured and is known as the dependent variable . Fixed variables such as light or temperature are kept the same each time. As a control or comparison, the scientist may add water to just one set of plants. Data is usually recorded in tables and presented as a graph in order to identify any trends or patterns.

> Quantitative measurements are observations that can be measured, e.g., height.

> Qualitative measurements, such as leaf colour, are less reliable, as they are unique to each observer.

“Adding more fertiliser will increase the rate of a plant's growth.”

A scientist examining plant growth

Concentration of fertiliser (%)

0%

Water

Plant height (cm)

Trial 1 Trial 2 Trial 3 Trial 4

The table shows the data collected by the scientist at different fertiliser concentrations. She noticed an unusual reading of 2 cm in the second trial for the 20% concentration. Readings such as this that do not fit with a pattern of data obtained are called anomalous readings or outliers. This anomalous

60

AVERAGE HEIGHT (CM) % CONCENTRATION

SAMPLE

In this example, the graph shows that as the concentration of fertiliser increases, the average height reached by the plant also increases. From this data, the scientist can

reading was ignored when calculating average height. Data is more precise when the results can be reproduced a number of times. Precision can be achieved by carefully keeping all the other variables in the experiment such as seed type, soil, light, and temperature constant.

It is important that scientists reduce possible sources of error during their investigation. In order to be accurate, the scientist must use suitable measuring equipment such as electronic balances

and metric rulers. The accuracy is a measure of how close a measured value is to its actual value. Reliability means that the same result will be obtained each time a measurement is taken.

1.3 Experimental Investigations: Preparation for CBA 1

During your journey as a scientist, you are asked to plan, carry out, and submit reports on scientific investigations. These skills are examined when you complete a Classroom-Based Assessment or Extended Experimental Investigation in 2nd year.

The following headings can be used to organise your scientific report.

Introduction

Hypothesis

This could be a short paragraph explaining why you picked this investigation and what you hope to discover.

This is usually a statement that can be easily tested or disproved by experimentation.

Research Variables and controls

This is a list of the sources that you found useful when planning your investigation. It is important to identify the dependent and independent variables as well as the controlled variables in the investigation. Controlled variables are fixed by you. Keeping the temperature constant while changing another factor is an example of a fixed controlled variable.

A list of all of the equipment or chemicals used will help you plan the investigation and will allow others to replicate your work if needed.

Safety

Materials and equipment Procedure

You should describe all the safety steps that were taken, and why.

You should include all steps and not assume that the reader knows what you did. You should describe how data was collected, and how you ensured fairness in the investigation. Well-labelled diagrams are useful to support your description. Diagrams of scientific equipment such as beakers and test tubes should be simple, side-view line drawings in pencil.

Results Analysis

Data is measurements or observations recorded during a scientific investigation. Tables are required to clearly display data collected during the experiment. Correct scientific units should be used at all times.

The data collected in the results can be used to calculate averages or to plot bar charts or line graphs in order to identify trends and patterns. You should describe the relationship between the variables.

Conclusion

You should state what you think the data means and whether or not you believe the hypothesis was supported, giving reasons from the data for your opinion. You should identify any strengths or weaknesses in the investigation and suggest areas of further study that could be undertaken.

1.4 Scientific Research: Preparation for CBA 2

Research is an important part of a scientist’s work. When carrying out scientific research and preparing a report, it is important to use scientific terminology and clear charts and diagrams, and to use references when using someone else’s work. These skills are examined when you complete a Classroom-Based Assessment or Science in Society Investigation in 3rd Year.

The following headings can be used to organise your research report:

Research question

Research information Evaluation of sources Impact on society

Decide what you want to know about the chosen topic, e.g., is a certain technology or scientific development useful of harmful.

Gather information about your chosen topic from a large number of varied sources, e.g., written text, interview notes, charts, tables, survey responses, observations, and diagrams. The research information should give a balanced viewpoint and present different arguments for your research question.

Explain why you trusted and used your sources. Who is the author? Can the facts be verified? Is the source biased? When was the information created? Did the author use a reliable source? Is the source detailed? Does it help answer the question?

Describe the impact of the topic on society. Who does it affect and how? Does it improve life? Does it harm the environment, and if so, how? Is it sustainable? Is it expensive? It is important to provide evidence that supports different viewpoints on whether or not the advantages of the scientific development outweigh any disadvantages.

Give an opinion on the pros or cons of the topic you researched. Discuss the pieces of evidence you found that helped you come to this opinion.

List all of the sources used in your research. Use the author’s name and the year they published their information. Name the website or book where this information can be accessed.

1.5 Sample Question A

Explain each of the following terms that are commonly used by scientists:

Hypothesis, experiment, data, variables, independent variables, dependent variables, control, anomalous data.

A hypothesis is a statement of what will happen to one variable when another variable is changed.

An experiment is an activity carried out to test a hypothesis.

Data is a measurement or measurements taken during an experiment.

Variables are factors that can change or be measured during an experiment.

An independent variable is a factor that is intentionally changed during an experiment.

A dependent variable is the factor that changes as a result of changes to independent variables.

A control contains an unchanged variable as a comparison.

Anomalous data means an unusual data reading that does not fit the general pattern.

1.6 Sample Question B

(i) Describe three safety measures that can be taken during a laboratory investigation.

(ii) How can a research source be judged as reliable ?

(i) 1. Gloves to protect the hands from contact with harmful chemicals

2. Safety glasses to protect the eyes from chemical splashes

3. Lab coats to absorb chemical splashes and protect the scientist’s clothing and skin.

(ii) To make sure that a research source is reliable, you can check that the author is known and suitably qualified. You could also check that the article is recent and relevant to the topic and that it is not biased and does not intentionally favour one side of an argument. Finally, you could check that the author has provided references for any facts quoted.

2.1 The Big Bang Theory

Humans have wondered about the origin of the Universe for thousands of years. The current model that is accepted by most scientists is known as the Big Bang theory and describes how the Universe is constantly expanding. The theory states that around 14 billion years ago, all

Expansion of the Universe

After the Big Bang, the Universe was filled with neutrons, protons, electrons, positrons, photons and neutrinos.

matter and energy in the Universe was focused into an extremely small point in space and then expanded rapidly, eventually forming stars, galaxies, and planets, which cooled and moved rapidly apart and are still moving apart today.

First stars and early galaxies

Modern galaxies

2.2

Evidence of the Big Bang

Radiation is a type of energy that can travel through space at the speed of light. Evidence that supports the Big Bang theory includes the differences in radiation from distant galaxies and the background radiation found all around us known as Cosmic Microwave Background Radiation (CMBR). Scientists can measure the radiation from distant galaxies and convert it to coloured bands called spectra. The positions of bands in the spectra from distant galaxies are different to their position in closer galaxies. The differences in band positions on the spectra are known as red shift and indicate that distant galaxies are travelling apart at higher speeds than closer ones are.

Big Bang Matter formed

2.3 Formation of Stars and Planets

Immediately after the Big Bang, the Universe expanded and began to cool, and the simplest elements, hydrogen and helium, were formed. Gravity slowly attracted these elements together to form large clouds of gas particles in space called nebulae. Within nebulae, the force of gravity increased and drew particles together with great force, and the first stars and galaxies started to form.

As stars became stable, nuclear fusion reactions combined hydrogen atoms together to form helium, producing huge amounts of light and heat energy. When all the hydrogen

and helium are consumed inside a star, it may explode as a supernova, throwing out gas and dust. Scientists believe that the energy from supernova explosions produced much of the material in the Universe, including some heavier elements such as iron, which collided and stuck together to form planets.

It is thought that the Earth was formed around 4.6 billion years ago from dust and gas left after the Sun formed. As the Earth gradually cooled, creating conditions in which life was possible, living things appeared on the new planet.

2.4

Sample Question A

Outline two pieces of evidence that support the Big Bang theory.

1. Red shift evidence – The bands on radiation spectra from distant galaxies show that galaxies are moving apart. When an object is moving away from the observer the wavelength of the light is stretched so the light seen is ‘shifted’ towards the red part of the spectrum.

2. Cosmic microwave background radiation is believed to be left-over energy from the cooling of the Universe after the Big Bang.

2.5 Sample Question B

Describe what scientists believe happened during the early formation of the Universe. Immediately after the Big Bang, the Universe expanded and began to cool. Smaller elements such as hydrogen and helium were formed and were drawn together by their own gravity, eventually forming stars. As stars consumed all of their hydrogen, they collapsed and went supernova, and nebulae containing heavier elements such as iron were formed. Planets were formed as dust, gas particles, and heavier elements orbiting stars began to clump together, so increasing their combined mass.

2.6

Sample Question C

Describe the life cycle of a stable star such as the Sun.

A star is formed when clouds of dust and gas in a nebula are drawn together by gravity. As the particles come together, heat is produced and eventually the hydrogen nuclei fuse together to make helium. This releases energy, which keeps the core of the star hot. In the stable phase, the outward pressure caused by the high temperature is balanced by the inward force of gravity. When all the hydrogen has been used up in the fusion process, the star may expand to become a red giant. When all the nuclear reactions are over, a star may begin to shrink under the pull of gravity and become a white dwarf. Some larger stars will continue making nuclear reactions and expand before eventually exploding as a supernova.

Morning of & night before

• Before you finish your study, check that you have everything you need ready for the following morning, exam number, pens, etc.

• Don’t sit up cramming, make sure you get a good night’s sleep.

• Eat well before the exam to keep up your stamina.

• Give yourself plenty of time to make sure you arrive on time.

• When you get to school avoid conversations with others about what they have revised, it might only increase your stress.

Once in the exam

• Read the paper very carefully.

• Always start with your strongest question.

Keepandcalm succeed

• Make sure to give yourself time at the end of the exam to re-read over your answers and check them.