Hot and Cold Reactions

This activity is an old favourite and always works well so today I tried it again with a new group of Science Club kids.

Here are the instructions:

 The students observed what was happening and wrote the following notes:

• There was a chemical reaction between the ingredients.
• The plastic bag puffed up so a gas must of been produced.
• The mixture fizzed and bubbled which also shows a gas must of been produced.
• The first mixture went really cold.  This is an endothermic reaction.
• The second mixture went really hot.  This is an exothermic reaction.
• Reaction 1 - we mixed a base (baking soda) with and acid (tartaric acid) so the reaction produced carbon dioxide.
• Reaction 2 - we mixed 2 bases so why did it fizz and bubble and produce gas???
• The water helped to mix the 2 powders together.
• Some of the bags popped when they filled with too much gas.

Carefully lowering in the water.

The mixture fizzes and puffs up the bag.

Watch out - It's going to explode!