Bacteria and viruses are everywhere. Most germs aren’t dangerous, but some can make us sick. Washing your hands reduces the risk of contagion. Here is an experiment perfect for the classroom or a group setting that illustrates why.
- One glass per participants
- 2-3 teaspoons baking soda mixed in 50 ml og water
- Litmus paper
- Fill all but one of the glasses with water. One glass should be filled with 2-3 teaspoons of baking soda and 50 ml water. The rest of the water should contain water only. Take care that all the baking soda has dissolved so that you can’t see which glass is “infected.”
- Ask what makes us sick and discuss what bateria and viruses are. Say that you are going to do an experiment which illustrates how illness spreads from person to person if you don’t wash your hands. The glasses are meant to illustrate hands. The participants infect each other by pouring the liquid from one glass into the glass of another participants. The participants then pour half the liquid back into the original glass.
- Tell the participants that one of the glasses contains a base that simulates the contagion. By using litmus paper at the end of the experiemnt, you can find out how many people caught the “illness.” Each participant should exchange liquids with to or three others. They have to write down the names of the people they mix liquids with.
- Let the students mix and then test to see if they have been infected by using litmus paper. How many people were infected?
- Now everyone makes a table, with two columns and one row per participant. Write down the names of all the students in the first column. In the second column, write a “+” next to the name of anyone infected, and a “-” for anyone healthy. Additionally, everyone infected writes a “+” next to the names of those they mixed with, and anyone healthy writes a “-” next to whoever they mixed with. If you’ve done this correctly, only two participants will have a pluss next to their names. One of these two people is the source of infection.
- Discuss what you could have done to prevent contagion.
More about hand washing and contagion
Bad hand hygiene is at fault for many hospital infections. Many studies show that hospitals that remind their employees to wash their hands have less contagion. A hospital in Geneva reduced its infections by half in four years after the administrators began to remind their employees to wash their hands continually. But not only hospital employees need to remember this. We should all be washing our hands, especially after getting home.