1. What is matter?
Everything around you is matter; matter is the stuff around you.
2. What are the general properties of matter? Define them.
The general properties of matter as mass and volume.
Mass is the amount of matter in a physical body.
Volume is the amount of space that a body occupies.
3. What tools do we use to measure the general properties of matter?
We can measure the mass of a body with scales and weighing machines.
To measure the volume of a solid body we can put it into a beaker of water.
4. Can two objects weigh the same but have a different form and volume? Explain it.
Yes, two objects that have a different form and volume can weigh the same if they have got the same mass.
5. Why does a wet T-shirt weigh more than a dry one?
Because the mass of the T-shirt has water added to it.
6. Why does a balloon deflate if you don’t tie a knot?
Because air tends to occupy the maximum space possible.
7. Why does a silver ring sink in water?
Because the density of silver is greater that the density of water.
8. What are other specific properties of matter? Define them and give examples.
Different types of matter have got specific properties that make them unique. These specific properties of matter are hardness and toughness, plasticity, ductility and elasticity, and conductivity.
Hardness is the ability to resist scratches and cuts. Diamond is a hard material and chalk is a soft one.
Toughness is the ability to resist breaking. Steel and granite are tough materials and glass and porcelain are fragile ones.
Plasticity is the ability to change shape without breaking. Plastic materials can we bend and fold easily.
Ductility is the ability to be stretched to make thin wires. Gold and silver are very ductile materials.
Elasticity is the ability to return to their original shape after we bend or stretch them. Rubber is a very elastic material.
Conductivity is the ability to conduct heat or electricity. Thermal conductors conduct heat easily, as many metals. Electrical conductors conduct electricity very easily, as cooper and gold. Thermal insulators are materials that don’t conduct heat very well, as wood. Electrical insulators are materials that don’t conduct electricity very well, as plastic and rubber.
9. How do we call materials that break easily?
We call them fragile materials.
10. Is gold an elastic material? Why?
No, it isn’t. Gold can not be bent or stretched and return to its original shape.
11. Give examples of two good thermal conductors and two good electrical conductors?
Iron and aluminium are good thermal conductors. Steel and cooper are good electrical conductors.
12. How do we call materials that are not good conductors?
We call them insulators.
13. Write two examples for each of the following definitions:
A hard, tough material: diamond
A soft, elastic material: sponge
14. What are the three states of matter? And their properties?
The three states of matter are solid, liquid and gas.
Solids have a constant mass, a constant volume and a stable shape.
Liquids have a constant mass, a constant volume and a variable shape.
Gases have a constant mass, a variable volume and a variable shape.
15. Which properties of solids are constant?
Mass, volume and shape are constant in solids.
16. What are the three examples of water in a solid form?
Ice, snow and hail are three examples of water in a solid form.
17. What does the state of water depend on?
The state of water depends on its temperature.
18. How can we cause a change of state in water?
We can cause a change of state in water by adding heat.
19. At what temperatures does water freezes and boils?
Water freezes at 0ºC and it boils at 100ºC.
20. Look at the drawing on page 125 of your textbook and explain what happens:
There is ice in a glass beaker which is being heated. The ice melts because of the heat and changes to liquid water. As we continue heating the beaker, the water boils and changes to water vapour.
