Infectious disease

An infectious disease is any disease caused by germs that can be spread from one person to another. Germs include viruses, bacteria and protozoa. What are some infectious diseases? 

This activity will simulate the spread of an infectious disease. A simulation is a simplified demonstration of a real biological process. Our simulation will show how an infectious disease can spread from one infected person to other people, who in turn infect others. 

Instructions 
1. Your teacher will give everyone a cup filled with a clear solution. This solution represents your body. Only one person in the class will have a cup that has been “infected”. Obviously, you should not drink from the cup. (In laboratory activities you should never drink or eat anything unless your teacher tells you that it is safe to do so.) 
2. In this part of the activity, you will interact with two other students. To interact with another student, pour all of your solution into your partner’s cup. Then have your partner pour all of the mixed solution back into your empty cup. Finally, pour half of the mixed solution back into your partner’s empty cup. Wait for the signal from your teacher, and then move to another part of the classroom and interact with a second student. After you have finished your second interaction, return to your seat. Estimate how many people you think will be infected. ________ 
3. Your teacher will come around and put an “infection indicator” in your cup. If you have exchanged solutions with the original infected person or someone else after they became infected, you are now infected and your solution will turn pink. If you have not exchanged solutions with anyone who was infected, your solution will not turn color. Next, your teacher will ask everyone who is infected to raise their hand. How many people were infected? ________ 
4. You will do another set of interactions, again beginning with only one student with an infected cup. This time there will be three rounds of interactions. For each interaction, be sure to move to a different part of the room with different students. Estimate how many people you think will be infected after each student has interacted with three other students. ________ After the teacher has come around with the indicator, write down how many people were actually infected. ________