Look around you. Some things are living, like a dog, a tree or you. Some things are not living, like a rock or a toy car. How can we tell?
Key idea
A living thing grows, needs food and water, and makes new living things like itself.
Why it works
Moving is not the test. A toy car moves, but it never grows. A tree stays still, but it grows taller every year and drinks water through its roots.
Worked example: Let's think it through
Is a cat living?
- Does a cat grow? Yes, a kitten grows into a cat.
- Does a cat need food and water? Yes.
- Can cats have kittens? Yes.
Answer: Yes, a cat is living.
Common mistake
Some children say a car, a cloud or a fire is alive because it moves, and that a tree is not alive because it stays still. Ask the three questions instead: Does it grow? Does it need food and water? Does it make new ones like itself?
For the grown-up. A seed is alive too: it is resting until it gets water. You can sprout a bean on a damp paper towel to see it wake up.