CONTENTS:
1.– Matter: .- General properties: mass, volumen.
. - Specific properties: density, hardness, solubility...
2.a.- States of matter: solid, liquid, gas.
2.b.– Phase transition: evaporation, condensation...
3.- Pure substances and mixtures.
4.- Chemical reactions: oxidation, combustion, fermentation
5.- Forces produce deformation and movement.
6.– Contact & non-contact forces: Gravity.
7.– Velocity.
1.– MATTER: is anything that has a mass (it is possible to be weighted) and occupies a space (has got a volume).
1.1.- GENERAL PROPERTIES:
a.- Mass: is the amount of matter in an object. We can measure the mass with a scale. The units of mass are: the gram(g), kilogram(kg) and tonne.
1000g = 1kg 1000kg = 1 tonne
b.- Volume: is the space that a substance or body occupies or contains. The unit of volume is the cm3 and litre
1000 cm3 = 1 l. 1000 litres = 1 m3
MASS: is the amount of matter in an object. VOLUME: is the space that a substance or body occupies or contains.
1.2.- SPECIFIC PROPERTIES:
. – Density: is the mass of an object divided by its volume.
d = _Mass (m) Volume (V)
The unit of density is kg/m3 or g/cm3 .
. – Buoyancy: the ability of an object to float.
If the object is less dense than water, it will float. If the object is more dense than water, it will sink.
. -Hardness: is the ressistance of a substance to being scratched.
. – Solubility: is the ability for a substance (the solute), to dissolve in a solvent Salted water is a solution. It is a mixture of salt (the solute) and water (the solvent).
USEFUL WORDS:
MATTER is anything that has a mass and volume and occupies a space
We can measure the volume with a graduated container.
2.1.– STATE OF MATTER:
We can find matter in three types of states:
a. - Solids have a fixed volume and shape, with particles close together and fixed into place.
b.- Liquids have a fixed volume, and its shape adapts to the container. Particles are still close together but move freely.
c.- Gases have variable volume and shape adapted to the container. Particles are not close together and move freely.
2.2.- PHASE TRANSITIONS:
Phase transitions describe changes between solids, liquids and gases. These changes depend on the increasing or decreasing of temperature.
. - Temperature increases:
. -Melting:
The change of a substance from solid to liquid. Melting point of water is 0ºC
- Evaporation:
The change on the surface of a liquid into a gas. Boiling is when the vaporization occurs within the entire mass of the liquid. Boiling point of water is 100ºC
. - Temperature decreases:
. - Condensation:
The change of a substance from gas to liquid.
. - Freezing:
The change from a liquid into a solid. Freezing point of water is 0ºC.
3.– PURE SUBSTANCES AND MIXTURES:
In nature, we can find substances in different ways:
. – Pure substances are substances formed by only one type of matter (eg. Oxygen, gold, water...).
. – Mixtures are subtances formed by two or more types of matter together (eg. salted water, granite, foods... )
a – Heterogeneous mixtures: we can see the different types of matter because they don’t have an uniform composition ( e.g.: a rock, a salad...)
b.– Homogeneous mixtures: we can’t see the different types of matter because they have an uniform composition (e.g.: salted water, air…)
USEFUL WORDS: .
solid
evaporation
liquid
boiling point
STATE OF MATTER: solids, liquids and gases.
gas
freezing
temperature
condensation
4.- CHEMICAL REACTIONS.
The most important chemical reactions are:
A chemical reaction is a process that transforms some chemical substances into other different substances called products. Types: oxidation, combustión & fermentation
4.1.- Oxidation is a chemical reaction in which a substance combines with oxygen.
Example: an object made of iron combines with the oxygen from the air (in a wet environment) so it will get rusted.
4.2.– Combustion is a very quick oxidation process, between a fuel (wood, paper…) and oxygen.
Every combustion produces heat and light.
4.3.– Fermentation is a process that converts sugar into other substances.
It is made by yeast, bacteria... It is used to produce alcoholic drinks (beer, wine…), dairy pruducts (yogourt), bread...
5.- FORCES.
There are forces that produce movement and others produce deformations on objects.
5.1.– Forces that make deformations: When a force acts on an object, it can produce some deformations on its shape. We divide objects in:
A.– Elastic objects change their shape only when the force is acting.
Example: spring, rubber…
B.– Plastic objects change their shape, and they do not get the previous shape after the force has finished.
Example: plasticine, clay…
C.– Rigid objects do not change their shape, the force breaks them.
Example: mirror, eggs…
USEFUL WORDS:
. – chemical reaction . – fermentation
. – oxidation . – combustion
elastic .
plastic .
rigid
.
A force is the push or pull on an object that produces a change on shape, position or movement.
5.2.– Forces that produce changes in position or movement:
1.– Contact forces: when an object produce a force on another object by contact (touching the other object).
2.– Non-contact forces: when an object interacts with another object without touching it (magnetism, gravity).
6.– GRAVITY.
In the 17th century, Isaac Newton discovered gravity.
Gravity is the force of attraction between every object and the Earth.
Example: an object falling down to the floor.
Gravity attracts objects to the centre of the Earth, from every place.
The force of attraction depends on the mass of the Earth and the object’s mass.
The quantity of this force is called weight.
So the weight of an object is different if the object is placed on the surface of the Earth than if the same object is placed on the surface of the Moon.
7.-VELOCITY or SPEED:
There are lots of forces that produce movement on objects (a car engine moves a car, a man moves a bicycle…). So, forces move objects a distance during a time. The relation between a distance (space) and the time is called “velocity” or “speed”.
Imagine we apply a force to a toy car, and it moves 1 metre during 1 second. Its velocity (or speed) is 1 metre per second. 1 metre
Velocity is the distance, divided by the time it spends.
Velocity = Units: m/s km/h Distance Time
Imagine a car goes from Madrid to Córdoba. The distance between these two cities is 400 km. The car spends 4 hours during the trip.
Let’s calculate its speed.
Remember: Velocity is the distance divided by the time.
Velocity = 400 kilometres =100 km/h 4 hours
