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Wikijunior:Big Book of Fun Science Experiments/Explosive foam

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You really need a proper science lab and a trained presenter to do this experiment. It is more of a demonstration than a participatory exercise.

Ingredients

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Images of most ingredients
Tub
Water
Soap
Beaker
Hydrochloric Acid
Magnesium Ribbon
Lighter
  • A tub which holds about 1 gallon
  • Water
  • Soap
  • A beaker or test tube
  • A stopper with a hole
  • Glass elbow and rubber tubing
  • Hydrochloric acid
  • Magnesium ribbon
  • A lighter

What to do

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  • Step 1: Fill the tub with very soapy water
  • Step 2: Fill the beaker or test tube about half way with hydrochloric acid
  • Step 3: Attach the glass elbow and the hose to the stopper
  • Step 4: Place the other end of the hose in the tub of soapy water
  • Step 5: Add a small amount of the magnesium ribbon to the beaker and quickly cover the top with the stopper; hold the beaker so it is lower than the tub and there are no kinks in the hose
  • Step 6: Bubbles will appear in the tub
  • Step 7: Pick up some bubbles with your hand and light them with the lighter; they should go up quite spectacularly without burning your hand
  • Step 8: When you get tired of playing with the bubbles, you can light the ones left in the tub all at once. FWOOSH!

Principle

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Magnesium and hydrochloric acid react to create hydrogen gas and magnesium chloride. The chemical equation looks like this:

Mg (s) + 2HCl (aq) --> H2 (g) + MgCl2 (aq)

Because Hydrogen gas is lighter than air, it travels up the tube and bubbles through the water. Hydrogen gas burns at a relatively low temperature and shouldn't harm your hand when you light it.