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Watch for bright flashes of flame!

Oranges are delicious and packed with vitamin C. Their peel is also packed with a flashy, flammable chemical secret!

Safety: This activity uses fire. Ask an adult to supervise.

You will need

• Orange
• Candle
• Lighter or matches

What to do

1. Find a tidy area to do this activity, with nothing flammable nearby, and away from other people and pets.
2. Peel the orange.
3. Take a nice big piece of peel. We found it worked well with a 5-centimetre-wide piece.
4. Light the candle.
5. Check that the area around the candle is clear and safe.
6. Hold the peel about 2 centimetres from the candle flame and bend it in half.
7. As you bend the peel, watch the candle flame. Did you notice any flashes or sparks?

What’s happening?

When you bend the orange peel, it gets squished and squeezed. Eventually, liquid inside the peel comes out. Some of it oozes out slowly, but some of it gets shot out, into the candle flame. And then, it catches on fire!

There are lots of chemicals in that liquid, including limonene. Limonene is the chemical that gives oranges their smell, and it’s very flammable. If applied directly to skin and eyes limonene can cause irritation, so don’t squeeze orange peel at other people!

Real-life science

Limonene is a handy chemical with many uses. It’s good at dissolving oils and some glues, so it can be found in cleaning products. It can be used as an insecticide to protect plants from pests. And of course, it smells nice, so it’s used as a fragrance in lots of orange-scented things, from hand creams to air fresheners.

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