7th Grade Bacteria Growth Lesson Plan

Topic: Bacteria Growth

Objectives & Outcomes

• Students will be able to describe how bacteria grow on Agar dishes and explain the differences in growth between different types of bacteria.

Materials

• Agar plates
• Bacterial culture (e.g. E. coli or Bacillus subtilis)
• Sucrose solution
• Iodine solution
• Microscopes or magnifying glasses

Warm-up

• Begin the lesson by asking students what they know about bacteria. Write their responses on the board.
• Next, ask students what factors might influence how fast bacteria grow. Again, write their responses on the board.
• Then, show students an Agar plate that is covered in bacteria and ask them to estimate how long it took for the plate to become so filled with bacteria.

Direct Instruction

• Explain to students that the factors they mentioned earlier can affect how fast bacteria grow. For example, temperature, oxygen availability, and nutrients can all play a role in how fast bacteria grow.
• Show students different types of bacteria and have them identify them using their textbooks or Google images.
• Then, using the petri dishes, demonstrate how to inoculate the Agar with different types of bacteria. Use a loop to scrape some bacteria from a culture tube and then use the loop to gently spread the bacteria over the surface of the Agar.
• Show students how to properly incubate the Agar plates and explain how to check for growth over time.

Guided Practice

• Have students work in pairs to inoculate and incubate their own Agar plates with different types of bacteria. They should record the type of bacteria they inoculated the plate with and any visible signs of growth over time.
• Then, have students present their findings to the class and discuss the differences in growth rate among the different types of bacteria.
• As a class, create a chart showing the growth rates of the different types of bacteria students tested.

Independent Practice

• Have students choose one type of bacteria to study in more depth. They should research this type of bacteria and create a presentation on its growth characteristics on Agar. The presentation should include a description of the type of growth observed, the length of time required for growth to be visible, and any other interesting or -significant findings.

Closure

• Ask students to reflect on what they have learned about the growth of bacteria on Agar. Ask them to give examples of the types of growth they observed and discuss any interesting or significant findings.

Assessment

• Observe students during the independent practice to see if they are following the experimental procedures and conducting the experiments accurately. Review the results of their experiments and -analyze their written reports for understanding of the growth of bacteria and the purpose of the use of Agar in the experiment.