Choose two inexpensive house plants that are the same size or grow them from seeds such as beans. Be sure both plants have the same soil and sunlight available to them.
Help the child to water one of the plants with water, and the other with the same amount of beer over a period of several days.
With the child, compare your plants each day for rate of growth and appearance. Discuss any differences you observe in regard to beer being a harmful substance.
Explain that egg shells are made of the same material as human teeth, only thinner. Break the egg and rinse and dry the pieces of shell and drop them into a cup of soda.
Wait a week and check to see the effects of the soda on the egg shell. Has the color changed? Is it as strong as it was when you put it in the container of soda? What do you think about the effect of soda on your teeth?
Light a cigarette and blow smoke from it onto a clean white cloth or tissue. Discuss where the smoke goes when there is no cloth or tissue to catch it. What do you think happens inside the bodies of smokers?