CSIRO is marching in Mardi Gras again this year (2 March)! To celebrate the kaleidoscope of human diversity, we’re flying this colourful rainbow quiz.

#1. If red is the first colour of a rainbow, what is the second colour?

Orange. The colours in a rainbow are ordered by the energy of that colour of light. A photon of red light has the lowest energy while violet has the highest energy. Orange is just a little more energetic than red, so it comes second. Sidenote: we love the energy you’re bringing to this quiz!

#2. We have 3 kinds of colour-sensing cells in our eye. What colours are they most sensitive to?

The colour-sensing cells in our eyes are called cones and there are 3 kinds: red-sensing, green-sensing and blue-sensing. Your brain combines information from lots of cones to see the rainbow spectrum. Scientists estimate we can detect up to 10 million different colours!

#3. True or false? We usually see rainbows in arcs but if you got up high enough (like in a plane), you can see a fully circular rainbow.

True. Every rainbow you see is a circular ring centred around your “antisolar point” – a spot pointed directly away from the Sun from your perspective. On the ground, your rainbow is partially blocked by the ground. Going higher raises your antisolar point, allowing you to see the full circle.

#4. Auroras make colourful light shows in the night sky. Where are you most likely to see an aurora?

Auroras occur mostly at the poles due to the way Earth’s magnetic field channels high-energy particles from the Sun. When these particles collide with atoms in our atmosphere, it makes a beautiful glow. Near the South Pole, Antarctica is a prime location for auroras.

#5. What is the abbreviation for gold on the Periodic Table?

Gold is known as Au on the Periodic Table. Au comes from aurum, the Latin word for gold. Many historians think “aurum” is related to Aurora, the Goddess of Dawn perhaps because both dawn and gold are shiny and golden. We think YOU are shiny and golden.

Was I right?


Congratulations! You are a real science whiz!

Oh dear! Better brush up before the next quiz!

A crowd of CSIRO staff in lab coats and Pride t-shirts stand all raising one fist in the air and smiling. They are arranged on a rainbow stairway. Rainbow flags with a white love heart in the centre hang in the backdrop. They are all celebrating Mardi Gras 2023.

CSIRO staff celebrate diversity at Mardi Gras 2023. Credit: CSIRO/Katherine Appleby

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