Wash your hands!
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ward
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science
Recommended Grade Level(s):
Appropriate for: K–8th Grade
Time Requirements:
Prep Time: 5 minutes
Activity Time: 5 minutes
Teaching Topics & Concepts:
This activity will provide your students with visual evidence that handwashing is the best way to reduce germs.
Materials:
• Bread
• Ziploc bags
• Gloves
• Hand Sanitizer
• Water (ideally sterile water)
Safety
• Beware of students touching their eyes after applying hand sanitizer.
• Water should be warm (but not hot) when washing.
• Though the mold that grows on your bread is harmless and already present in the environment, it is still
best not to inhale mold spores in a concentrated form. At the end of the growth period, completely seal the
Ziploc bags before allowing the students to handle them to perform their observations.
• Students with a penicillin allergy can participate in the setup of the experiment, but should not participate
in the data collection after incubation.
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Procedure:
1. Label at least 1 clean, unused Ziploc bag for each of the test conditions below.
"Gloved Hands"
• Apply gloves. Remove a piece of bread from the bag and place it into the corresponding Ziploc bag.
2. "Bare Hands-Hand Sanitizer"
• Roll up sleeves. Apply hand sanitizer and allow to dry. Using bare, sanitized hands, remove a piece of bread from
the bag and place it into the corresponding Ziploc bag.
3. "Bare Hands-Unwashed"
• Using bare hands that have not been washed, remove a piece of bread from the bag and place it into the
corresponding Ziploc bag.
4. "Bare Hands-Soap/Water"
• Roll up sleeves and wash hands thoroughly with soap and warm water.
– Scrub and lather for the entire time while singing the alphabet song.
5. (Mostly) Seal the bags
• You'll need to allow for air exchange for the mold to grow. Only zip about ¾ of the zipper. Leave it un-zipped,
but do not leave it gaping open.
• Place bags in a dark, warm spot where they will not be disturbed for at least 10 days. Record the changes you
see day-to-day.