How do whales sleep and why do helium balloons float? Try our kids’ quiz

Hush a bye, baby. Illustration: Hennie Haworth/The Guardian

1. The drawing above is of a humpback whale with its baby. How do whales sleep?

   1. They lay down on the ocean floor to sleep

   2. Whales rest by hanging vertically or horizontally or by swimming slowly next to another whale

   3. They find a sea sponge to use as a pillow and then they nod off

   4. Whales don’t need to sleep

2. Beatrix, 8, asks: what do (some) spiders do with their old webs?

   1. They live in them until they fall apart

   2. Eat them

   3. Smash them up so no other spider can use them

   4. Offer them to another spider in return for food

3. Sophie, 9, asks: how many bat species are there?

   1. 10,000

   2. 5,200

   3. 1,400

   4. 575

4. Delilah, 5, asks: why do helium balloons float?

   1. Because they’re pulled upwards by the sun

   2. Because they aren’t affected by gravity

   3. Because helium is lighter than air

   4. Because they have jet engines inside

5. Martha, 10, and Zadie, 7, ask: which insects have the biggest brains?

   1. Ants

   2. Ladybirds

   3. Bees

   4. Giant Japanese hornets

Solutions

1:B - Whales rest in the water, hanging vertically or horizontally, or sleep while swimming slowly next to another whale. They are only half asleep, so remember to surface to breathe. One half of the brain snoozes, then the other half takes a turn!, 2:B - Orb web spiders eat the silk their old webs are made of. Its amino acids go back into the spiders’ digestive systems and into their silk glands to be made into a new web. It’s spider recycling!, 3:C - There are more than 1,400 species of bats. They live in most parts of the Earth, except really harsh deserts and super cold polar regions. The biggest are flying foxes, with a 1.5 metre wingspan., 4:C - Helium balloons float because of the helium inside them! The air we breathe is made of lots of gases, mostly oxygen and nitrogen which are quite heavy. But helium – found in pockets under the Earth’s surface – is lighter than air, so a balloon with helium in it will float., 5:A - Scientists think that ants are one of the most intelligent insects and have the largest brains of them all. Each has 250,000 brain cells (a human has 86bn) and they are very clever.

Scores

1. 5 and above.

2. 4 and above.

3. 3 and above.

4. 2 and above.

5. 0 and above.

6. 1 and above.

• Molly Oldfield hosts Everything Under the Sun, a weekly podcast answering children’s questions, out now as a book. Does your child have a Christmas-themed question they would like to feature in a special festive quiz? Submit one here