1. Seb, 9, asks: how long can crocodiles stay under water without coming up for air?

   1. Only about three minutes as their lungs are very small

   2. 30 minutes

   3. Two hours

   4. Eight hours or more

2. Tilly, 8, asks: why does your skin go purple under your eyes when you’re sleepy?

   1. Having purple skin under our eyes made us safer in prehistoric times, as the colour purple helped to ward off predators

   2. When you’re tired, your eyelids get so heavy that it bruises the skin underneath and makes it look purple

   3. Lack of sleep can cause blood vessels to expand, which makes the skin look purple

   4. Nobody knows

3. Niels, 10, asks: is it easier for a tornado to travel over grass or concrete?

   1. It doesn’t seem to make a difference but scientists still aren’t sure

   2. Concrete

   3. Grass

   4. Tornadoes don’t exist

4. Lonnie, 7½, asks: can the sun melt all plastics?

   1. It can only melt some plastics as its surface isn’t hot enough

   2. Yes

   3. No one knows

   4. It’s not hot enough to melt any plastics – some probes sent to the sun were made out of polystyrene

5. Emi, 7, asks: who invented prisons?

   1. The Victorians

   2. The Romans

   3. We’re not sure – either the ancient Egyptians or the ancient Greeks

   4. King Henry VIII

Solutions

1:D - Crocodiles can hold their breath under water for eight hours – and sometimes even longer. They do this by slowing their heart rate down to 2-3 beats a minute., 2:C - When we’re sleepy or have been deprived of sleep, it can often cause blood vessels to expand. The skin under your eyes is very thin and delicate, so this causes it to look a bit bluish-purple., 3:A - The roughness of the terrain can affect the tornado’s shape, but we can’t tell which surface it would find it easiest to pass over. There is some evidence that when a tornado travels from a smooth surface such as a field to trees or houses, it can make the tornado increase in intensity., 4:B - The temperature of the sun on its surface is about 5,500C. The plastic widely agreed to have the highest melting point is polyimide, which melts at 500C., 5:C - It’s hard to pinpoint where prisons began. There are records of them in ancient Egypt, and ancient Greeks integrated prisons into the running of society, with the Greek philosopher Plato theorising that they could be used for reform rather than just punishment.

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.