Materials- Half a lemon
- 1 tsp water - Cotton bud - Paper - Heat source such as, lamp, match, or light bulb |
Procedure1) Squeeze half a lemon into a bowl. Remove all of the seeds.
2) Add 1 tbs of water. 3) Dip the cotton bud into the bowl and write a message with it on the paper. 4) Wait for it to dry. 5) Heat the paper by placing it near the heat source. 6) Watch the letters turn brown! |
Scientific TheoryLemon juice is acidic and weakens the paper. It contains carbon compounds, which are colourless at room temperature. When the heat is added, it breaks down these compounds, releasing the carbon. Once it came in contact with air, a process called oxidation occurred. This is when there is a loss of at least one electron. When the lemon had the skin on, it created a barrier against oxidation. Afterwards, the cells came in direct contact with the air and the oxygen molecules than started to burn them. This made all of the remaining acid turn the writing brown.
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