Two nails were placed in water and two in cooking oil. After three days, only the nails in water rusted. Why didn’t the nails in oil rust?
Rust occurs because of a reaction between metal, oxygen, and water. The oil prevents water and oxygen from touching the nail, so the nail cannot rust.
Give an example of where metals are used for safety around the house.
Burglar bars, fences, locks (any appropriate example).
What is the opposite property of flexible?
Rigid/stiff
Give any two differences between mammals and birds.
E.g.: (1) Mammals birth live young, birds lay eggs. (2) Mammals have fur, birds have feathers.
How do recycling plants separate steel from aluminum?
Steel is magnetic and aluminum is not. A giant magnet is used to attract and remove the steel from the conveyer belt.
Why is gold used to make jewellery?
It is malleable, so it can be easily shaped into nice designs, it is pretty, and it does not rust.
Consumers that eat both plant and animal material are called:
Omnivores
A baby insect is called a ____.
Larva or Nymph
In the following food chain, why is there an arrow from the decomposer to the producer?
The decomposer breaks down plant and animal material and returns the nutrients to the soil. The living plants use the nutrients for growing.
What do we call a material that does NOT conduct heat or electricity?
An insulator.
What will happen to these two magnets?
They will repel each other (push each other away).
What are raw materials?
Materials that we get from the earth (e.g. plants, animals, minerals).
Give an example of how plants can be interdependent on animals.
Plants can depend on animals for: pollination, seed dispersal, and nutrients (soil decomposers).
Plants have 5 requirements for photosynthesis, name any 3.
Sunlight, Water, Carbon dioxide, Soil, Chlorophyll