Natural Sciences and Technology - Grade 4 - Term 2

[Pages:31]Natural Sciences and Technology - Grade 4 - Term 2

Topic 6 ? Materials around us

Unit 1 ? Solids, liquids and gases

14 April ? 15 April 2020

Matter makes up all the materials and substances that exist on Earth. Everything around us is matter (Everything around us is either a solid, a liquid or

a gas) Matter/ materials can exist in three different forms ? solids, liquids and gases We call these three forms the states of matter

Properties of the three states of matter: o Solids Has a fixed shape You cannot change the shape easily, you will need some force to change the shape E.g. If you hit a brick with a hammer, its shape will change o Liquids Does not have a fixed shape A liquid will take the shape of the container you pour it in, it flows E.g. If you pour milk into a glass, it takes the shape of the glass. When you pour it into a bowl, it will take the shape of the bowl

o Gases Has no shape but it takes up space A gas moves around freely and spreads out into open spaces. You cannot keep it in an open container, the container must be closed You cannot see, feel or smell some gases E.g. Air is made up of different gases. If you blow up a balloon and tie it off, the gas (air) is trapped inside. But when you untie the balloon, the gas escapes and the balloon shrinks again.

Unit 2 ? Change of State

16 April ? 17 April 2020

A substance changes from one state of matter to another when it gains or loses heat

A thermometer is used to measure temperature (how hot or cold something is) o Temperature is measured in degrees Celsius (?C) o Water freezes at 0 ?C o Water boils at 100 ?C

Melting o Changing from a solid to a liquid by adding heat o E.g. If ice cream gets warm and melts

Evaporating o Changing from a liquid to gas by adding heat o E.g. When you boil water in a kettle steam (gas/water vapour) is released

Condensing o Changing from gas to liquid by cooling it down o Gases condense when they lose heat o E.g. When you boil water in a kettle, hold a plate above it. The steam will collect on the cold plate and change back into water

Solidifying o Changing from liquid to solid by cooling it down o E.g. If you put water in the freezer it will change into ice

Unit 3 ? The water cycle

20 April ? 22 April 2020

The Earth has a limited amount of water The movement of water from the land and sea, to the air and back again Water will change its state through evaporation, condensation, melting and

freezing

o Water on the Earth's surface evaporates and moves up into the air as water vapour Water from the sea, rivers, dams is heated by the sun, and changes into gas

o The water vapour cools and condenses as it rises into the air The gas collects in the sky because it cools down

o Drops of water high in the air form clouds The more water that collects, the darker the clouds become

o Drops of water will fall to the Earth as rain Water in the clouds can freeze and will fall to the Earth as snow or hail. It will melt when it touches the warm surface of the Earth

o Rain, snow and hail bring water back to the Earth's surface

Topic 6 ? Activity

23 April ? 27 April 2020

1. Use the words to complete the sentences. states solids cool solidify shape space melt condense evaporate

a. The ________________________ of substances are solid, liquid and gas. b. __________________ keep their shape. c. Liquids take the ________________ of the container they are in. d. Gases have no __________________, but they take up

__________________. e. When we heat solids, they ______________ and become liquid. f. When liquids are heated they _______________ to form gases. g. When gases ________________ they ________________ to form liquids. h. When liquids cool, they _____________________ and become solid.

2. Identify the states of matter (materials) in each of the pictures.

__________________

_________________

__________________

_____________________

__________________ 3. Which changes listed below are examples of melting and which are examples of

solidifying? Give a reason for each answer. a. You have a piece of chocolate in your pocket on a hot day.

b. You put jelly in the fridge to set.

c. You put butter in a pan so that you can fry an egg.

4. Identify the change of state in the following parts of the water cycle:

a. Clouds form

__________________

b. Snow forms

__________________

c. Water vapour forms

__________________

d. Snow becomes liquid water

__________________

Topic 7 ? Solid Materials

Unit 1 ? Raw and Manufactured Materials

28 April ? 30 April 2020

Raw materials are natural material such as wood, sand and clay that can be used to make things

Natural materials come from nature Sometimes we can use raw materials as they are When people change raw materials to make something else, we call it

manufactured materials Raw materials that are used to make other materials:

o Sand is used to make glass Rocks are broken down by the wind and water to become sand Sand is heated and melted into liquid The liquid can be shaped into different objects When it cools down, it solidifies to become glass objects

o Clay is used to make ceramics Clay is made from very fine wet sand It can be shaped into different objects The objects are heated in ovens to become hard These ceramic objects are hard but brittle (it can break easily)

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