Lesson Plan #:AELP-BIO000
Submitted by: JIM L. TORGERSON, NORTH SEVIER MIDDLE SCHOOL, SALINA, UTAH
Endorsed by: These lesson plans are the result of the work of the teachers who have attended the Columbia Education Center’s Summer Workshop. CEC is a consortium of teacher from 14 western states dedicated to improving the quality of education in the rural, western, United States, and particularly the quality of math and science Education. CEC uses Big Sky Telegraph as the hub of their telecommunications network that allows the participating teachers to stay in contact with their trainers and peers that they have met at the Workshops.
Date: May 1994
Grade Level(s): 6, 7, 8
OVERVIEW: The students will be able to describe bacteria as it relates to them.
PURPOSE: By gaining an understanding of bacteria, students will have the knowledge to deal with bacteria, their advantages and disadvantages.
OBJECTIVE(s): STUDENTS WILL BE ABLE TO:
BACKGROUND INFORMATION: Bacteria are one-celled organisms. Bacteria are the smallest organisms that are clearly alive. The three major types of bacteria are cocci, bacilli, and spirilla. Bacteria need food, water, and a suitable temperature in which to live. Some bacteria cause disease, while others are not harmful. Some bacteria help in the reduction of plant and animal waste to soil nutrients; others are used in the production of cheese.
RESOURCES: LIFE SCIENCE TEXT BOOK, BIOLOGY TEXT BOOKS, ENCYCLOPEDIA, ANY OTHER RESOURCES THAT RELATE TO BACTERIA THAT ARE AVAILABLE.
You will need to start with pictures and/or drawings of the different types of bacteria. The students need to have a basic understanding of bacteria before you start the activity. Hold a short discussion about bacteria.
You will need the following materials:
Disposable or non-disposable petri dishes can be obtained from biological supply companies.
Make sure students have had experience labeling types of bacteria before starting this activity.
CAUTION: BE SURE THE PETRI DISHES REMAIN SEALED WITH TAPE AND THEY ARE DISPOSED OF PROPERLY FOLLOWING THIS ACTIVITY.
Also, this activity will take a few minutes each day for several days to complete.
ACTIVITIES AND PROCEDURES: Give each student a prepared sterile petri dish (one that already contains the growing media nutrient agar). MAKE SURE STUDENTS DO NOT OPEN THE DISH UNTIL THEY ARE READY TO EXPOSE IT. Have students expose their dish to any environmental conditions they can think of: i.e., chalk dust, leaves, saliva, dead flies, grass, soil, dirty hands, water, etc. I usually save two dishes for my use: One dish is for the control (just tape it shut without exposure). The second dish I have someone in the class kiss it to show bacteria growth of bacteria that come off the lips. It is important that students do not put too much stuff in the petri dish. Limit to two very small substances, one on each side of the dish. After the students inoculate (expose) their dish they need to take notes on time of exposure and what the agar was exposed to. Students need to put their name on a small piece of masking tape, taped off to one side of their specimen. The student needs to give the dish to the teacher. The teacher needs to tape the dish shut. The exposed petri dish can now be put in the incubator. Set the incubator around body temperature. Don’t forget to add a little water in the bottom of the incubator to keep the humidity up.
IT IS IMPORTANT THE DISH REMAINS SEALED FROM THIS POINT ON- MAKE SURE STUDENTS DO NOT TURN THE DISH UPSIDE DOWN WHEN YOU HAND THEM BACK FOR OBSERVATIONS UNLESS THEY ARE FAIRLY DRY CULTURES.
24 Hours later hand out each student their petri dish. (It is important you don’t start this activity on a Friday) Each person needs to record observations of their dish. When finished put dishes back in the incubator. 48 hours later (from initial exposure) hand out each student their petri dish for more observations. Don’t forget to hand out the control dish. When finished put the dishes back in the incubator. 72 hours later (from initial exposure) hand out the petri dishes for the last time. Have students take their final observations and after a class discussion make some conclusions. Now you are ready to relate and review bacteria types to the bacteria cultures they have in their petri dish. You may want to wait for a full class period to do the microscope work. Hand each student a prepared slide containing the bacteria types. (Some schools will have the necessary equipment to make and stain their own slides off the bacteria the students have cultured. Please do not try to do this unless you have had the proper training in preparing bacteria mounts due to the disease potential from pathogens). Put the slide on the microscope stage. Focus the microscope, using the techniques discussed in a previous lesson. Have students draw on a piece of paper what bacteria types they are able to see. Have students identify the bacteria they are drawing. Have students use reference sources to identify and label the bacteria being viewed. After the lab, discuss the advantages and disadvantages of bacteria (i.e., bacteria diseases, decomposition of organic material, etc.) This will probably be done in another class period. Also discuss how bacteria affect their environment.
TYING IT ALL TOGETHER:
Math: Have students conduct a poll to determine if people consider bacteria helpful or harmful. Tally the records and make graphs for the subgroups polled such as: elementary students, teens, high school students, parents, and grandparents.
English: Have students compose a story about the thoughts of a plant or animal that lives in an environment where there are no decomposers. They could describe the anguish about rising level of waste, etc.
Art: Draw and color bacteria as you would see them in their natural surroundings.
Health: Identify and discuss ten health practices that deal with illness or health. i.e.; food poisoning.
History: Have students research the historical effects of major diseases. Some diseases might be bubonic plaque, polio, influenza, malaria, cholera, scurvy, smallpox, etc.