Science experiments give students the opportunity to determine if what they believe about a theory or process is accurate. When exploring germ theory and how to prevent disease, students learn that hand washing can prevent the spread of disease by killing viruses and bacteria. An experiment using common bacterial hand soap, dish soap and hand sanitizer offers students the chance to compare options they use on a daily basis. The experiment also encourages the students to use effective hand washing practices.
- Hand washing instruction sheet
- Antibacterial soap in a pump
- Dish soap in a pump
- Paper towels
- Germ-glowing gel
- Ultraviolet light
- Hand sanitizer in a pump
- Slide cover slip
- Distilled water
- Record sheet
Give each student a hand washing instruction sheet, and demonstrate the correct way to wash hands. Wet your hands and apply soap using a pump dispenser. Vigorously rub your hands together to create a rich lather. Thoroughly scrub your hands for a minimum of 20 seconds. Include the area under the nails, between the fingers, up the wrist, and on the front and back of both hands. Thoroughly rinse your hands, and dry them with a paper towel. Spread a germ-glowing gel on your hands, and hold them under an ultraviolet light so students can see where germs may hide -- indicated by glowing a bright white.
Divide students into three groups, and have one group wash their hands with antibacterial soap. Instruct the second group to wash with ordinary dish soap, and tell the last group to clean their hands with hand sanitizer. Set a timer for 20 seconds to let students know when they have washed their hands for the recommended time period. Examine the hands of each student under an ultraviolet light to see how effectively he washed his hands. Send students back to rewash their hands, if the ultraviolet light reveals significant amounts of the gel remaining.
Wipe each student's palm with a slide cover slip, and use it to prepare a wet mount slide. Place a drop of distilled water on the slide, and then place the edge of the cover slip beside the water. Lower the cover slip over the water and press it down. Place a drop of stain beside one edge of the cover slip and a piece of paper towel next to the opposite edge. Allow the paper towel to wick the stain under the cover slip. Remove the paper towel after the entire area under the cover slip is stained.
Examine the slides under the microscope for the presence of germs and bacteria. Use the record sheet to note which substance each student used for hand washing, and whether you detected germs or bacteria on the slide. Compile the results for each hand washing substance and determine which option provided the cleanest hands.
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