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Properties of ElementsActivity for Kids

Splitting Water Molecules DIY

Duration: 20-30 min
Difficulty: Medium
Cost: $0 to $10

Learn how to split water molecules into the elements of hydrogen and oxygen!

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Material List

2Pencils
1Pencil Sharpener
19-Volt Battery
2Wires with Alligator Clips
1Glass of water
1Pinch of Salt
1Pair of Safety Glasses
Adult supervision

Instructions

1Pour half a teaspoon of salt into a glass of water and mix it.
2Remove the eraser (including the metal part) from two pencils (use pliers to help).
3Sharpen both ends of each pencil to make double-ended pencils.
4Attach alligator clips to each terminal of the battery and then to each pencil tip (black part).
5Place the other ends of the pencils into the water (you should see gas bubbles start to be made).

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How It Works

The gas bubbles forming around the pencils in the water are caused by electricity being used to split water molecules into the elements, hydrogen and oxygen. Hydrogen gas forms on one of the pencils, and oxygen gas forms on the other. The pencil that is making a lot more bubbles than the other is the hydrogen gas. This is because water has 2 hydrogen atoms for every 1 oxygen atom (H2O).