- Define and explain Testing Properties in your own words
- Use key terms such as property accurately
- Apply what you have learned to new examples and questions
- Avoid the common mistakes learners make with this topic
This lesson focuses on Testing Properties: carry out simple fair tests to find out which materials are waterproof, magnetic or stretchy.
Carry out simple fair tests to find out which materials are waterproof, magnetic or stretchy.
Key ideas
Sorting by one property
When you sort materials, pick just one property at a time, for example magnetic or not magnetic. A fridge magnet sticks to steel but not to plastic, wood or glass, so steel goes in one group and the others go in another. Using one rule keeps the groups fair and makes the pattern easy to see.
Matching materials to jobs
People choose materials for their properties: windows are made of glass because it is transparent, and wellington boots are made of rubber because it is waterproof and bendy. A material that is perfect for one job can be wrong for another — glass windows let in light, but glass would be a poor choice for a football. Good designers always ask what the object needs to do first.
Key term — property: Something you can observe about a material, for example whether it is hard, shiny, rough or stretchy.
Name two properties you could test to sort a pile of different spoons.
Any two sensible properties, for example whether they are magnetic and whether they are waterproof (metal versus wood).
Answer: Any two sensible properties, for example whether they are magnetic and whether they are waterproof (metal versus wood).
- Sorting by colour alone Colour is a poor sorting rule because many different materials can be the same colour. Sort by a property that tells you something useful, like hardness or waterproofness.
- Saying a material is useless because it failed one test Failing one test does not make a material useless. Fabric soaks up water, which is bad for a raincoat but perfect for a towel — the job decides which properties matter.
Practice
Plastic is a good choice because it is smooth, so children slide easily, and waterproof, so rain does not damage it. Other sensible answers with two properties are acceptable.
It is waterproof, so rain cannot soak through it.
False. Iron and steel are magnetic, but metals such as copper and aluminium are not.
It is fair because it uses one clear property, and every button fits into exactly one of the two groups.
Quick check
Which of these best defines "property"?
Which material would be best for a window: wood, glass or fabric? Give a reason.
- Testing Properties: carry out simple fair tests to find out which materials are waterproof, magnetic or stretchy.
- Sorting by one property: When you sort materials, pick just one property at a time, for example magnetic or not magnetic.
- waterproof: Does not let water soak through it, like a raincoat fabric.
- Watch out for: sorting by colour alone