Science Activity: Make a Fizzler

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If you wanted to cool down a liquid, you would probably put it in a cold place. If you wanted to warm it up, you would probably put it in a warm place. In this activity, you'll discover that certain chemicals can change the temperatures of liquids.

1. Get Ready

Three Alka-Seltzer tablets
Three large glasses that can each hold at least 1/2 cup of water
Kitchen thermometer
Water

2. Do and Wonder

Break each tablet in half.

Add 1/2 cup of water to one of the glasses. Take the temperature of the water in the glass. Predict what might happen to the water temperature if you put half an Alka-Seltzer into it.

Drop half an Alka-Seltzer into the water. Wait 30 seconds, and then take the temperature of the water again. Observe the reaction that occurs.

Pour 1/2 cup of hot water in one glass and 1/2 cup of the coldest water you can get in the other glass. (You can use the hot and cold water from the faucet.) Do you expect the reaction of the Alka-Seltzer with the hot water to be the same or different from the reaction of the Alka-Seltzer with the cold water? Write down your predictions.

Put half an Alka-Seltzer in each glass of water.

3. Think and Write

Make a list of the active ingredients found on the Alka-Seltzer package. Next to each item, write down your best guess about what that ingredient is supposed to do for the person taking the Alka-Seltzer.

The starting temperature of the water may have had something to do with the speed of each reaction. Based on what you observed, would you say that a high temperature makes the reaction happen more quickly or more slowly?

Explanation

Alka-Seltzer contains crystals and powder. When  you put a tablet in water, the chemical reaction uses up some of the water's heat energy, which makes the water temperature drop.