Continue your classroom investigation of chemical reactions with the following companion exercises for each lesson!

Lesson 1

The Alka-Seltzer Fizz
An Alka-Seltzer tablet contains aspirin, sodium bicarbonate, and citric acid. When placed in water the sodium bicarbonate and citric acid react with each other to form bubbles of carbon dioxide gas.

Lesson 2

Goldenrod Paper Indicator
A color change can mean that a chemical reaction has taken place. It can also give some hints about the type of chemicals that are causing the reaction. The color changes in goldenrod paper can be used to investigate chemical reactions.

Lesson 3

Cleaning Dirty Water with a PUR Packet
Water is a basic need for people everywhere. But, what happens when people only have access to water that is dirty or infected with bacteria? How can you clean dirty water? One clever strategy is to create tiny chemical nets which capture small particles of dirt.

Soap Scum
Hard water is water that has minerals dissolved in it. In some areas, minerals like calcium, iron, or magnesium are naturally dissolved in the water. These minerals can interact with soap and create soap scum which is a precipitate.

Lesson 4

Glowsticks and the Rate of a Reaction
In chemical reactions, energy can be given off or absorbed in the form of heat but it can also be given off or absorbed in the form of light. Glow sticks use a chemical reaction between a substance called luminol and hydrogen peroxide to release energy in the form of light.