INFECTION WARS
Grades 2-5

This lesson will provide the students with an understanding of how our bodies fight infection. The students will observe red blood cells, white blood cells and different bacteria under a microscope. The students will make drawings of their observations and multiply bacteria using the same pattern (mitosis) as bacteria uses to multiply. The students will write and act out a short play starring the key players (red blood cells, white blood cells, antibodies and the dastardly bacteria) to demonstrate their knowledge of infection fighting.

Magic School Bus: Inside Ralphie (SCETV)
What's in the News: Space - Gravity (WPSX)

Students will be able to:

• distinguish red blood cells from white blood cells;
• calculate how bacteria multiply by using patterns;
• describe how bacteria can enter the body;
• describe how white blood cells fight bacteria;
• construct a play and perform it to demonstrate their knowledge of how infection is fought off in the body.

Per class

• overhead transparency showing white and red blood cells.
• overhead transparency showing different bacteria.

Per group of two

• blood slides
• microscopes of 400 X or better

Per student

• pencil
• blue and red pencil
• lined paper
• worksheet #1
• worksheet #2 and #3

• antibiotics - destroys or weakens germs
• antibodies - a substance, made in the blood, that destroys or weakens bacteria
• bacteria - tiny living bacteria
• detection - a discovery, finding out
• infection - causes a disease
• plasma - the clear liquid that makes up our blood
• uvula - the piece of flesh that hangs in the back of our throat, from the Latin "uva" which means grape

The vocabulary will be presented on a chart with class discussion. Using vocabulary words on post-its, sentences will be written providing closure. The students can volunteer to place post-its in correct sentences.

On the overhead projector project the red blood cells, white blood cells and transparencies of bacteria. Ask, "Can anyone guess what these are and what might happen if they met?" Accept and record all answers on chart paper.

To give students a specific responsibility while viewing say, 1.) "List the names of the helpers our blood uses to fight infection." 2.) "Watch the video to see if you were correct when predicting what might happen when the bacteria meet up with the blood cells." Say, "You are going to see a video that explains what happens when we have a cold and sore throat."

BEGIN the video immediately following, "I think Ralphie shouldn't have stayed home today." PAUSE after mom says, "I'll check in later." Ask, "What do you think his mother gave him?" Accept all answers, i.e. Children's Tylenol, cough syrup, antibiotics. FAST FORWARD to, "What's going on with my body anyway?" CONTINUE video and PAUSE after, "The FNN news team is nearing the disaster area." Have students use mirrors, open their mouths and visualize the uvula.

RESUME video and PAUSE after, "See anything yet?" Point out the larynx and explain that it is their voice box and makes noise by vibration. RESUME video and PAUSE after Ralphie asks, "The question is, why is it red and swollen?" Ask, "Does anyone know why Ralphie's throat is red and swollen?" Remind students to listen for the answer.

RESUME video and PAUSE again after Ralphie asks, "Wait a second. I've got it." Ask students to predict what will happen.

RESUME video and PAUSE when Ralphie says, "But we still don't know what's making me sick." Give the students an opportunity to identify the names they just learned about of the helpers in the blood that help heal cuts. Use the vocabulary chart to reinforce.

RESUME video until Ralphie says, "Those look exactly like white blood cells. Look, you can even see the wires." STOP. Remove tape from VCR and replace with, What's is the News: Space-Gravity. BEGIN video. PAUSE after, "The white blood cells were then counted, tested and examined to see if they were doing their job."

FAST FORWARD after, "...doing their job" to a still picture with the caption, "Microbiologist, a scientist who studies small living things." PAUSE after, "Maybe some of you will want to become microbiologists, too."

Distribute worksheet #1. Have the students preview slides on the microscope and draw their observations in color. Say, "We are going to be microbiologists today. Let's look in the microscope like the microbiologist and see the white and red blood cells. Draw your observations carefully. Remember that scientists are very exact and your drawing should be that way, too." Discuss the nucleus of the white blood cell and discuss the differences in white and red blood cells.

RESTART Magic School Bus: Inside Ralphie from the point where you left off. PAUSE tape to have students answer Ralphie's question, "What are those things?" (bacteria) RESUME video until Mom says, "Any good doctor knows the best cure is complete rest."

At this time the bacteria will have been seen on the tape. It will demonstrate that they multiply by splitting. Ask, "Does anyone see a math pattern?" Once you have the correct answer, talk about mitosis and cell splitting. Explain that cells reproduce themselves each time by splitting in half and making two.

Distribute Worksheet #2 and #3. Have the children complete the worksheet using math patterns demonstrated in the video. When completed, discuss how quickly bacteria can multiply.

RESTART video and play to the ending. STOP video after, "Athlete's Foot."

Divide the class into groups. Say, "You are going to work together to write a short play about an infection war using the information you received by watching the video." Ask the students who some of the characters could be in the play. Elicit antibodies, bacteria, etc. Remind students there must be a good vs. evil and a problem that must be solved. Say, "Your play must teach us how the blood rescues our body from infections, i.e. you need to have a character that the bacteria will attack. How will the bacteria attack? What will the bacteria be called? Have the white blood cells come to save the leading character."

Allow time for the students to complete the assigned task. Reserve time for each group to present their skit.

Plan a field trip to a lab to learn how slides are used to diagnose disease.
Invite the Red Cross to speak on the collection and importance of blood.
Invite a pharmacist to discuss different antibiotics and their roles in fighting different bacteria.

Art: Make clay models of different bacteria. Make beaded necklaces to represent bacteria.

Language Arts: Write a story from bacteria's point of view.

Social Studies: Find examples to share where germs were used against the enemy. For example, in Massachusetts blankets infected with small pox were given to the Native Americans.

Science: Collect bacteria samples from the bathroom, water coolers, desks, doorknobs, etc. and grow on agar plates. View under a microscope and label bacteria.

Master Teacher: Mary Hanson

Click here to view the worksheet associated with this lesson.