How often do eclipses happen and how hot is lava? Try our kids’ quiz

1. Angus, 10, asks: how often do lunar and solar eclipses happen?

   1. They’re extremely rare – once in a century

   2. They happen most days somewhere on Earth

   3. They happen once a month

   4. Lunar eclipses usually happen once or twice a year, and solar eclipses between two and five times a year

2. Arlo, 7, asks: how hot is lava?

   1. It’s as hot as the hottest pitta bread in the world

   2. It’s as hot as fire

   3. It’s five times cooler than the sun’s surface

   4. It’s five times hotter than the sun’s surface

3. Alby, 4, asks: how fast does the Earth spin?

   1. About 100km an hour

   2. About 1,600km an hour

   3. A million miles an hour

   4. Too quickly to count

4. Raai, 7, asks: how fast do jellyfish swim, without counting the current?

   1. It depends on the jellyfish

   2. No one has ever measured how fast a jellyfish swims

   3. They’re one of the fastest sea creatures in the world

   4. Jellyfish swim as fast as sailfish, the fastest fish in the ocean

5. Sebby, 9, asks: could you jump on Jupiter?

   1. You could but you’d soar high up into the sky

   2. Yes, but it’s much harder to jump than on Earth

   3. No – if you stand on Jupiter you sink right away, so don’t ever try!

   4. Jupiter is very bouncy, so if you jump it’s like jumping on a trampoline

Solutions

1:D - Lunar eclipses happen roughly once or twice a year. Sometimes there are years with three and sometimes there are none! Solar eclipses happen roughly two to five times a year. A total solar eclipse happens every 18 months on average., 2:C - Lava is between 800 and 1,200 degrees Celsius but the surface of the sun is about five times hotter, measuring 5,800C. , 3:B - Earth rotates around its axis at about 1,600km an hour, measured at the equator. Near the north pole and south pole the speed is very slow – only about 0.00008km an hour!, 4:A - Scientists aren’t sure, but in a 2015 study of the jellyfish Rhizostoma octopus, their swimming speed was measured at 2cm to 8cm a second, with an average of 5cm a second. However, box jellyfish may be much faster. The US National Ocean Service estimates they reach speeds of up to 2 metres a second!, 5:B - On Earth you can jump about 60cm, but Jupiter has a stronger gravitational force, so you could only jump about 24cm. On Mercury, however, you’d be able to jump about 1.58 metres.

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.

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