Fins, gills and scales
How does a fish breathe under water? Meet the fins, the tail, the gills and the scales, and find out why a dolphin is not a fish.
Read
Fish live in water. They have a backbone.[3][2]
Fish do not have lungs. They breathe with gills, small slits just behind the head.[3]
Fins help a fish swim forwards, backwards, up, down and sideways. The tail fin pushes the fish through the water.[3][2]
Scales cover a fish's body like a coat of armour. They protect the fish from getting hurt.[3][2]
The biggest fish of all is the whale shark. A dolphin is not a fish: it breathes air with lungs.[5][7]
Try it: Tail power
You need
- A long tray or washing-up bowl with a little water
- A small cork or plastic bottle top
- A pencil
- A piece of stiff card about the size of your hand
- Towels
Safety
Use only a little water and wipe up spills straight away so nobody slips. Stay at the tray; do not splash.
What to do
- Float the cork at one end of the tray.
- Hold the pencil upright in the water behind the cork. Wave it gently from side to side. Does the cork move?
- Now hold the card upright in the water. Wave it from side to side in the same way.
- Which one moves the cork further: the thin pencil or the wide card?
- Look at a picture of a fish. Which part of the fish is like your card?
Play: Fish or not a fish?
Does it breathe with gills and have fins? Tap the right group.
Your best score is kept only on this device. Nothing is sent anywhere.
Quiz
Other ages: Ages 10–11 · Ages 15–16