Choosing materials by their properties — Chemistry, 7–10 years
A material is useful because of what it can do, not just because of its name. Looking at properties such as hardness, flexibility, waterproofing and conductivity helps us choose the right material for a job.
Properties are clues
A property is something we can observe or test about a material. Glass is transparent and hard, rubber is flexible and waterproof, and copper lets electricity pass through easily. One material can have several useful properties, while another may be better for a different job.
Why test materials?
Builders and designers need materials that will work safely and last. Guessing from colour or shape is not enough: a pretty cup may crack, and a strong-looking wire may not conduct electricity. Simple tests turn a choice into evidence, so the material matches the problem.
Choosing a raincoat
The job is to keep a person dry while allowing movement. Test cotton, paper, plastic and wool by placing a few drops of water on each, then bend each sample. Plastic keeps water out but may feel less breathable; cotton bends well but absorbs water. A coated fabric can combine useful properties.
One test is not enough
It is reasonable to choose the hardest material, because hard objects often seem strongest. But hardness does not tell us whether a material is flexible, waterproof or safe near heat. A good choice considers the whole job and tests the properties that matter for it.
Materials all around us
This thinking is used in shoes, phones, bridges, cooking tools and sports equipment. A saucepan needs a heat-resistant body and a handle that does not conduct heat quickly. A bicycle needs materials that are strong without being unnecessarily heavy. The best material depends on the job.
Keep exploring
Other languages
Loading MyLeoNes™…