Germs are tiny living things or particles that can move from place to place on hands, desks, pencils, toys, and food. Many germs are too small to see, so a school project can use glitter, pepper, or safe glow powder as a model. This makes invisible spreading easier to observe and discuss.
Hand washing matters because clean hands can help keep students, families, and classrooms healthier.
Key Facts
- Wash hands with soap and water for at least 20 seconds.
- Soap helps loosen oils and dirt so germs can rinse away with water.
- A model is a safe stand-in for something real, such as glitter representing germs.
- Germs can spread by contact, such as hand to hand, hand to object, and object to hand.
- Percent removed = (amount before - amount after) / amount before x 100.
- Best hand washing order: wet, soap, scrub, rinse, dry.
Vocabulary
- Germ
- A germ is a tiny organism or particle, such as a bacterium or virus, that can spread and sometimes cause illness.
- Soap
- Soap is a cleaning material that helps lift oils, dirt, and germs from skin so water can wash them away.
- Model
- A model is a simple representation used to study or explain something that may be too small, large, or complex to observe directly.
- Contamination
- Contamination happens when germs or unwanted materials get onto a surface, object, or part of the body.
- Variable
- A variable is something in an experiment that can change, such as washing time, amount of soap, or water temperature.
Common Mistakes to Avoid
- Rinsing with water only: this is wrong because water may remove some dirt, but soap helps loosen oils where many germs can stick.
- Washing for only a few seconds: this is wrong because short washing often misses fingertips, thumbs, between fingers, and under nails.
- Touching the same clean object after using germ powder or glitter: this is wrong because it spreads the model germs and can confuse your results.
- Changing many variables at once: this is wrong because you cannot tell whether soap, scrubbing time, or another factor caused the difference.
Practice Questions
- 1 A student counts 40 glitter specks on their hands before washing and 8 specks after washing. What percent of the glitter was removed?
- 2 A class tests 5 students. Each student washes for 20 seconds. How many total seconds of hand washing are tested, and how many minutes is that?
- 3 In a germ spreading project, why is it useful to use glitter or glow powder instead of real germs, and what does the model show about hand washing?