3
Many materials in one thing
Workbook 2: Topic 3.3, pp. 35–37
GoalSay that many objects are made of more than one material, and give a reason for each part.
New words
frame · the main part that holds other partstyre · the rubber ring round a wheelhandle · the part you hold
Explanation
Many objects use more than one material, because each part has a different job. A bicycle has a metal frame because metal is strong and rigid. The tyres are rubber because rubber is flexible and grips the road. The saddle is soft so it is comfortable to sit on. A house has bricks for strong walls, glass for transparent windows and tiles for a waterproof roof. Choosing the right material for every part makes a good object.
Worked examples
A frying pan has a metal pan and a plastic handle. The metal is strong. The plastic handle stays cooler to hold.
Lola’s school bag has soft cloth to hold her books, a plastic zip and metal buckles.
A house is built from brick, glass, wood and tiles. Each material does a different job.
Class activity
Material detective (with an adult): choose an object, such as a bicycle, a toy, a pair of scissors or a boot. Find as many different materials as you can. Draw the object and write the material and a reason for each part.
Practice
1
Why are a bicycle’s tyres made of rubber?
Rubber is flexible and grips the road.
2
A school chair has metal legs and a plastic seat. Why are the legs made of metal?
Metal is strong and rigid, so the legs hold a child up without bending.
3
Name two materials used to build a house, and say why one of them is used.
For example: bricks, because they are strong; glass, because it is transparent; wood; tiles.
4
Why does a pair of scissors have a plastic handle and metal blades?
The metal blades are hard and strong enough to cut. The plastic handle is comfortable to hold.