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Sizing up the Sun – a quick quiz

By , 9 May 2018

Here’s a quiz to get your brain pumping. Test your knowledge of floating metals, and not one but two questions about the closest star to home – our Sun!


Congratulations! You’re a real science whiz!

Oh dear! Better brush up before the next quiz!

#1. What is a pademelon?

Pademelons are like small wallabies and can be found in New Guinea, Tasmania and the east coast of mainland Australia.

#2. True or false? Aluminium is less dense than water, so it always floats on water.

False. Aluminium is denser than water, so it will typically sink unless it’s hollowed out. There are times aluminium will float on water, such as an empty aluminium can. In this case, it’s actually the air inside the can that’s making it float!

#3. At what temperature are Celsius and Fahrenheit the same?

At -40 degrees Celsius, it’s also -40 degrees Fahrenheit. Fahrenheit degrees are spaced closer together than Celsius, so water freezes at 32 degrees Fahrenheit or 0 degrees Celsius.

#4. What element is the Sun mostly made of?

The Sun is about 70% hydrogen, 28% helium and 2% other elements.

#5. In which month is Earth closest to the Sun?

Earth is closest to the Sun in January. It’s about five million kilometres closer than in July, which might seem like a long way, but it’s only a fraction of the average 150 million kilometres to the Sun.

Was I right?

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Black lightning bolt in purple circle


  1. I would query answer #4 as there are numerous papers that suggest the sun is predominantly iron

    1. Hi John,
      I checked in with our Astronomy and Space Science department, and they were very definite that the Sun is mostly hydrogen. They said that, like most stars in our galaxy, our Sun is a main sequence star, and it is powered by the fusion of hydrogen into helium.

      Thanks for the question,

  2. too difficult to use the web

    1. Hi Sue,
      Thanks for your feedback! looks like our blog migration hasn’t solved all our problems. We’ll keep working on it!


  3. There must be something wrong with your program. I got all the answers correct but was told I got 4/5 80%

  4. Hi David,
    Sorry to hear that! I just tried the quiz and I can get 100% – can I ask which browser you’re using?


  5. All worked fine for me….the sun is definitely not mostly iron – any references that say so – ignore them…the sun being mostly iron does nothing to explain why it keeps so bright – orthodoxy has it is mostly hydrogen which I am gonna stick with. Hydrogen fusion can keep it going for billions of years. Interestingly Helium was first discovered on the sun from the sun’s spectrum in 1868 during a solar eclipse. Now we use it in party balloons.


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