Aim: To show a model to demonstrate the transmission of a disease as it spreads through the classroom.

Materials: wax pencil, empty jars. Safety goggles. Gloves, dropper, "stock" solutions, phenol red indicator

1. Obtain a jar of stock solution from your teacher.

2. Choose a classmate to be your partner. Each of you takes one dropperful of the solution out of your jar. Empty your dropper into your partner’s jar while your partner does the same in your jar. Gently swirl the solution.

3. Record the name of your partner and repeat steps 2 and 3 twice.

4. Add on dropperful of phenol red indicator to the solution in your jar. Record the color of your solution.

5. If your solution turned yellow, you were infected. If your solution turned red, you were not infected.

6. If you were infected, write your name and the names of your partners on the board.

7. Deduce the original source of the infection (there was only one "contaminated" stock solution) as well as the routes of transmission of the infection.

Conclusion: Write a paragraph stating your conclusion and support it with your observations.

1. Diagram the route of transmission in your class.

2. Were you infected? If so, who infected you? Did you infect someone else?

3. What is the maximum number of infected people after two rounds? After all three rounds?

4. Phenol red turns yellow in acidic solutions and red in basic solutions. What represented the infectious microbe in this model?

5. Why is this lab called "Better Red Than Dead?"

6. Some diseases, such as tuberculosis, can be transferred through the air; a person need only breathe in the microbes to be infected. AIDS, however, requires the transfer of body fluids to transmit the virus that causes the infection. Which mode of transmission does this simulation represent?

7. What precautions could you take to prevent getting AIDS?

8. Following is a story describing the transmission of a disease at a family reunion. Read it and carefully answer the questions that follow.

Prior to a family reunion, old man Petri (his father invented the petri dish), telephone his son, Centrifuge, and his daughter-in-law, Pipette, to wish them well. He could not attend their annual reunion banquet, so he asked them to send his regards to the family. A funny lot, they would father for dinner, despite the fact that some family members refused to talk to others.

At the party that night, their own children came to the banquet with their spouses and children. Centrifuge greeted son Beaker and daughter-in-law Funnel, but would not greet their children. He greeted his daughter-in-law Spatula, but refused to greet his son, Ringstand, whom he always considered to be a ne’er -do-well.

Meanwhile, Pipette did greet their son, Ringstand, as well as her daughter Mortar and son-in-law Pestle. However, she also had no use for the grandchildren, whom she found to be nuisances. Each of the children then greeted his/her spouse, but refused to greet their own brothers and sisters. (Nice family!)

Beaker passed the greeting onto his daughters, Scalpel and Forceps, while Mommy Funnel greeted their child Probe. Spatula greeted her son Coverslip, while Ringstand greeted Slide. Mortar shook hands with Balance, while Pestle shook hands with Microscope and Dropper. Then the siblings passed on the greetings. Scalpe – Forceps, Forceps – Probe, Coverslip – Slide, Balance – Microscope, and Microscope – Dropper. Finally, in a n effort to break down family barriers, Probe greeted Coverslip, Slide greeted Balance, and Dropper welcomed Scalpel.

But alas, after the banquet and fellowship, an infection ran rampant through the family.

· Assuming that anyone shaking hands with an infected person will contract the disease, list all family members infected if the source of the disease is Centrifuge.

· Extra Credit: Create your own story to show transmission of a disease. Identify the characters with "scientific" references. i.e. organelles in a cell, organs in the body, famous scientists or scientific names of organisms.

I Got It From Agnes   by Tom Lehrer

I love my friends, and they love me, 
We're just as close as we can be. 
And just because we really care, 
Whatever we get, we share! 
I got it from Agnes, She got it from Jim. 
We all agree it must have been Louise who gave it to him. 
She got it from Harry, Who got it from Marie, 
And everybody knows that Marie Got it from me. 
Giles got it from Daphne, She got it from Joan, 
Who picked it up in County Cork, A-kissing the Blarney Stone. 
Pierre gave it to Sheila, Who must have brought it there. 
He got it from Francois and Jacques, Haha, Lucky Pierre! 
Max got it from Edith, Who gets it every spring. She got it from her Daddy, 
Who gives her everything. She then gave it to Daniel, Whose spaniel has it now. 
Our dentist even got it, And we're still wondering how. 
But I got it from Agnes, Or maybe it was Sue, Or Millie or Billie or Gillie or Willie, 
It doesn't matter who. It might have been at the club, Or at the pub, or in the loo, And if you will be my friend, Then I might...(Mind you, I said "might")... Give it to you!

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