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What Do You Know About Microbes? (pre-assessment)

Author(s): Barbara Tharp, MS, and Nancy Moreno, PhD


This activity offers several opportunities to extend student learning. Consider having students address one or both of the questions on the slide by designing their own investigations.

Students could begin by estimating the length of time one must wash his or her hands to be sure they are clean and free of harmful microbes. You might have students record their estimates on sticky notes to create a class bar graph of data.

Next, ask students to plan experiments that involve several different variables, such as water temperature, type of soap (including anti-bacterial), and length of time washing hands under the water. If it is not mentioned, make sure students develop and agree upon a uniform method for "contaminating" hands with Glo Germ™ powder. Then have each group record and implement its plan. Results should be presented to the class.

As an alternative, you may wish to follow a pre-set plan, such as the example below.

Six groups of students. All use the same technique for contaminating hands with Glo Germ powder and follow the same basic hand-washing method. The variables are the presence (or absence) of soap and the time spent washing.

  • Group 1. Wash 10 seconds without soap.
  • Group 2. Wash 20 seconds without soap.
  • Group 3. Wash 30 seconds without soap.
  • Group 4. Wash 10 seconds with soap.
  • Group 5. Wash 20 seconds with soap.
  • Group 6. Wash 30 seconds with soap.

Funded by the following grant(s)

Science Education Partnership Award, NIH

Science Education Partnership Award, NIH

Grant Number: 5R25RR018605