What is it made of?
Look at your chair, your cup and your shoes. Each one is made of a material. Wood, metal, plastic, glass, rubber, paper, cloth and rock are all materials.
People choose materials carefully. Would you want a chocolate teapot? A paper umbrella? A glass pillow? Of course not! Each job needs a material with the right properties.
What are properties?
A property is something you can notice about a material using your senses or a simple test. Here are some properties:
| Property | What it means | Example material |
|---|---|---|
| Hard | Doesn’t press in or scratch easily | Rock, metal |
| Soft | Squishes when you press it | Cotton, sponge |
| Flexible | Bends without breaking | Rubber, cloth |
| Stiff | Doesn’t bend | Wood plank |
| Waterproof | Water can’t get through | Plastic, rubber |
| Absorbent | Soaks up water | Paper towel, sponge |
| Transparent | You can see through it | Glass, clear plastic |
| Opaque | You can’t see through it | Wood, metal |
| Rough | Bumpy to touch | Sandpaper, bark |
| Smooth | Even to touch | Glass, a marble |
| Magnetic | Sticks to a magnet | Iron nails, paper clips |
Choosing the right material
| Object | Material | Why? |
|---|---|---|
| Window | Glass | It’s transparent, so you can see out. |
| Raincoat | Plastic or rubber | It’s waterproof, so you stay dry. |
| Rubber boots | Rubber | Waterproof and flexible, so you can walk. |
| Spoon | Metal | It’s hard and strong, and it’s easy to wash. |
| Towel | Cotton | It’s soft and absorbent. |
| House frame | Wood | It’s strong and stiff. |
One object, many materials
Some objects use more than one material. A pencil has wood (to hold), graphite (to write) and rubber (to erase). A bicycle has metal for the frame, rubber for the tires and plastic for the seat.
Natural and made by people
- Natural materials come from nature: wood, wool, cotton, stone.
- Made materials are made by people: plastic, glass, paper.
Even made materials start with things from nature. Glass is made from sand. Paper is made from trees.
Testing materials
Scientists test materials to find their properties. You can too!
- Water test: Drip water on it. Does it soak in or roll off?
- Bend test: Gently bend it. Does it bend or snap?
- Magnet test: Hold a magnet close. Does it stick?
- Light test: Hold it up to a window. Can light pass through?
Reusing and recycling
Some materials can be recycled into new things. Old plastic bottles can become fleece jackets. Old paper can become new paper. Choosing materials that last and can be recycled helps take care of our planet.
Common mistakes
- Thinking all metals are magnetic. Iron is, but aluminum foil and copper pennies are not.
- Mixing up the object and the material. A cup is the object; glass is the material.
Try it yourself
- Collect five objects: a spoon, a sock, a plastic bag, a paper towel and a rock.
- Test each one: Is it waterproof? Flexible? Magnetic? Transparent?
- Record your results in a chart.
- Which material would be best for making an umbrella? Why?
Quick recap
- Everything is made of materials.
- A property is something you can notice about a material.
- Hard, soft, flexible, waterproof, transparent and magnetic are properties.
- We choose materials based on their properties.
- Testing helps us find out a material’s properties.