NOT BY THE NAKED EYE
Grades 3 - 5

Students will be made aware of the part germs play in causing diseases. They will also discover that germs are microorganisms that can not seen by the naked eye. Germs are everywhere. The class will see some germs that cause sore throats, infect cuts, and cause pimples. Students will also learn that germs multiply rapidly.

Students will grow cultures of the organisms that live in a pond, under our fingernails, or in the dust that gathers on our window sills. The class will also learn that eating well, exercising, and keeping clean will help us to avoid getting sick.

"Reading Rainbow: 'Germs Make Me Sick' (#404)"
"Head to Toe: 'Fighting Germs and Disease' (#10)"

Students will be able to:

• Identify three types of germs or microorganisms from pictures;
• describe microorganisms as being either helpful or harmful;
• identify germs that cause sore throats, infections and pimples by picture;
• prepare a culture that will grow organisms from their own mouth;
• model behavior that will contribute to their own better health;
• encourage better health in their school community, and
• multiply using tens, hundreds and thousands.

• a culture medium in a petri dish-like container
• cotton swabs (one for each student)
• one microscope and some slides
• one set of base ten blocks and teacher-made place value cards

Take attendance as you usually do. Tell the students what the attendance is and ask if there is anything unusual about today's attendance: Is it perfect, unusually high or low? Ask the students if they know why students are usually absent from school. Ask how we know when someone is sick? What do their parents do to find out if they are very sick? What does a doctor do to tell if their sore throat is strep or not? Ask the students what the doctor is looking for when he does a throat culture?(germs) When you get the answer germs from the class, ask the students to tell you what germs are. Record their answers on the chalkboard. Then have one student look up the meaning of germs in the dictionary and read it to the rest of the class.

Write the word microorganism on the chalkboard and discuss how germs are microorganisms. Ask the class if they have ever seen microorganisms. Ask the students to tell you some phrases people say about sickness, such as, "Feed a cold ,starve a fever," "Going outside with a wet head will cause a cold," "An apple a day keeps the doctor away," etc. . Write down their answers on a chart. Ask the students to tell you why they think the statements are true or not. Have the students draw pictures of what they think germs look like. T ell them to turn their papers over and say, "Let's see how your pictures compare with pictures of real germs."

The focus for viewing is a specific responsibility or task(s) students are responsible for during or after watching the video to focus and engage students' attention. Tell the students that you are going to show them some microorganisms that live in pond water . Instruct them to raise their hands when they can describe three types of organisms found in the pond water.

START the Reading Rainbow episode where Levar Burton says, "The world's best private eye is a microscope." PAUSE the tape when the students have identified three kinds of microorganisms. Have the students draw the organisms that they have seen on chart paper for the class. Ask the students to raise the hands when they see an expert on germs and they can tell what her job is. FAST FORWARD the tape and START it where the narrator says, "Nobody likes to get sick." PAUSE after the narrator says that Betty is a medical technician. Discuss with the class other jobs that Betty might have held that would also require knowledge of germs. Instruct the children to write a list on chart paper, with each student recording the career they suggested. Say to the students, "We are now going to see three types of germs the could make us sick if we really had them here in the classroom." PAUSE the tape after each germ is shown and they hear what it causes. At each pause, have the students draw and label each germ. STOP after we learn about the germ for pimples. Ask the students how frequently the germs multiplied. Explain that every 20 minutes would mean more then once every half hour. Ask if they can tell you exactly how many times the germs would multiply in an hour. Show the students some home-grown mold. (The back of the teacher's refrigerator might be a good source.) Tell the students that mold is grown from micro-organisms. Ask the students if they know a way to protect themselves from germs. Tell them that this next clip will show them three ways, and that they should watch carefully to see if their predictions were correct.

FAST FORWARD the video and START where the narrator says," Three ways to stop bacteria are...." STOP the video after the words, "Don't share cups." Tell the students that there is another way to prevent getting sick. It is why we go to the doctor when we are well. Tell the students that they should raise their hands when the doctor tells Sarah what that is.

BEGIN ITV Series-Head to Toe #10, where Sarah and her father are at the clinic. PAUSE where the doctor says, "Today we are going to give you a vaccine in the form of a shot." Discuss the shots your students have had and why they have had to have them. Ask the class, "What would be worse, a shot or an illness that could be very serious?" Ask the students to tell you other ways that we can prevent getting sick. Make a list on the chalkboard. FAST FORWARD the video and START where the host says, "Germs can get into your body." and pause after the types of medicines and vaccines are mentioned. Have a student make checks on the chalkboard next to ways mentioned in the video, and to write any other ways that were mentioned.

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Note to the Teacher:
Both the medical technician and the doctor in the videos are women, and offer an opportunity to encourage girls as well as boys to pursue careers in math and science.

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Have the class decide what there is in the classroom that they would like to examine under the microscope to see if they can see the microorganisms. If you have enough microscopes, have the students look at these things in groups of two or three. Have each group list the things that they looked at, and record and draw what they saw. If many students must take turns at one microscope, have the other students prepare posters to help remind themselves of things they should do to prevent the spread of germs in the classroom as well as at home. (e.g., washing hands before eating , after using the bathroom or handling pets; not sharing cups, glasses , combs and brushes or foods that can't be separated before eating.) Each student should be given a petri dish with a culture medium in it. The students should label the dish with their name. They will work with a partner to use a cotton swab to get a sample from the inside of their cheek and transfer to the petri dish. The cultures shall be placed in a cabinet and looked at the next couple of days to see if anything has grown.

The math component should emphasize the information that germs can multiply by the tens hundreds or thousands every twenty minutes. (Remind the children that the film had told them there are about 10,000 germs on the head of a pencil. Ask a student how many pencils he or she has in there desk. Ask him or her how many germs they could have on the top of all their pencils if 10,000 germs were on each one. Ask how would they find out. Accept either addition or multiplication.) Discuss and show how multiplying by ten brings the number up to the next place value. (Use base ten blocks to demonstrate how this occurs.)

When the students can demonstrate the same to you and each other, introduce the number response cards (made by Open Court Publishing Company and adapted by the teacher) to reach ten thousands or hundred thousands. Finally, introduce the quick trick of counting zeros in both factors to get the correct place-value before multiplying the other parts of the factor. Use the enclosed worksheet to assess understanding.

The students could use the Internet to contact the Centers For Disease Control at ( http://www.cdc.gov/epo/mmwr/mmwr.html) or contact (http://www.yahoo.com/Health Disease and Conditions) to learn more about how disease is spread and how we can contain it.

The students can check the rest rooms of their favorite restaurants for the mandatory health notices reminding employees to wash their hands.

Students may use the Internet to communicate with children from other schools see if there is a difference in the absentee rate in different schools, or to investigate what other schools do to help keep their students healthy.

The students could interview the school nurse and/or the school doctor to find out the general health trends in the area and/or how they can become health care professionals or members of the science field.

Literature: Germs by Dorothy Hinshaw Patent (has great photos of germs magnified.) Lumps, Bumps and Rashes by Alan E. Nourse The Good Health Series edited by Mario Orlandi and Donald Prue Health and Hygiene by Dorothy Baldwin A Day in the Life of a Sports Therapist by David Paige

Music: Sing the song in the back of the Teacher's Guide for Head To Toe (Replay the section on the tape where the song is sung and have the students sing along.)

Art: The students could make posters for the classroom, the cafeteria and the rest rooms to remind their friends to wash their hands, cover their mouths when sneezing, and to get plenty of sleep to help avoid getting sick.

Master Teachers: Kathleen E. Gibbons and Donna L. Clovis