Lemon juice Christmas cards science experiment : Fizzics Education


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Lemon juice Christmas cards

Lemon juice Christmas cards

Follow FizzicsEd 150 Science Experiments:

You Will Need:

  • A Lemon
  • Bowl
  • Paper
  • Some pens
  • A spotlight or a hairdryer
  • Cotton swab


Lemon juice Christmas cards science experiment - materials needed
1 Lemon juice Christmas cards science experiment - squeezing a cut lemon to get the juice

“Putting lemon juice into the bowl”

Squeeze some lemon juice into the bowl.

2 Lemon juice Christmas cards science experiment - dabbing cotton bud into lemon juice

Dab the tip of your cotton swab into the lemon juice and use it to paint your Christmas card and message.

3 Lemon juice Christmas cards science experiment - writing with lemon juice

Let your card dry.

4 Lemon juice Christmas cards science experiment - using a hair dryer to heat the lemon juice writing

Decorate you card some more with the pens.

Turn on the spotlight, or hairdryer, and use it to heat up the paper from a safe distance. DO NOT USE AN OPEN FLAME TO DO THIS.

5 Lemon juice Christmas cards science experiment - lemon juice writing after applying heat

“Lemon juice on paper after heating “

Move your card over the heated light, or hairdryer until lemon juice changes colour.

Stop before the paper starts to burn.

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Why Does This Happen?

This is the classic ‘invisible ink’ experiment. Lemon juice is acidic and contains sugar.
The acid from the lemon juice affects the paper, effectively weakening the paper structure. Adding heat to the paper causes the acid-affected paper to burn first. Additionally, sugar will form caramel when heated, this is present in small quantities within the lemon juice.

Variable testing

  • Try other fruit juices – which work best?
  • Also, try other weak acids; does this work as well?
  • What will happen if you add extra sugar to your painting solution?

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