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This experiment will show how Alkali reacts with Acid. 

Material Used

• Red Food Coloring 
• Modelling Clay/Plasticine
• Baking Soda
• Vinegar


1.  Shape some modelling clay into the shape of a volcano and use your thumbs to make a well for the inside of the volcano.
2.  Put a spoonful of baking soda in the volcano well.
3.  Put a few drops of red food coloring in the well.
4.  Pour a bit of vinegar on top of the baking soda and red food coloring and stand back.


A bubbling lava (volcano) erupts. baking soda + vinegar = mini explosion. A vigorous release of carbon dioxide.


The vinegar is an acid (acetic acid) and the baking soda (sometimes called bicarbonate of soda) is a base. When combined, they react and give off carbon dioxide gas, which is what causes the bubbles. However, carbon dioxide is heavier than air, so these bubbles collect at the surface of the liquid and cause frothing.

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