World Water Day Resources
Our bodies and our planet are both made from approximately 70% water. Water helps to keep our bodies healthy in so many ways, whether it is drinking to stay hydrated and wash all kinds of waste from our bodies, or the ocean spitting garbage out onto the shores to clean itself and the life within it. Today, on this World Water Day, as our schools are closed and so many children are focusing on handwashing, it might be fun to learn exactly how germs pass from one of us to another. Here's a quick lesson for the young at heart....
GERM DETECTION AND HAND WASHING
Many of the germs that cause diarrhea, viruses and waterborne diseases come from exposure to human and animal feces. Many illnesses can be prevented by good hygiene. Hygiene education and promotion of good hand-washing practices, especially in primary schools, can save lives. Do you know that each year, nearly 22 million school days are lost to the common cold alone? When children practice healthy habits, they miss fewer days of school. Thoroughly washing hands is the single most important thing students can do to keep from getting sick or infecting others. The typical person’s hands contain millions of microbes. Most are naturally occurring and are harmless, but some may be disease-causing germs. Vigorous hand washing—for at least 20 seconds and using soap—is the best way to lift off the microbes and rinse them away.
The experiment in this activity vividly shows students the importance of handwashing. It can be conducted with an ultraviolet (UV) light, also called a “black” light, and powder or gel that simulates the presence of germs on students’ hands. Examples include products that are commercially available from Glo Germ (www.glogerm.com) or Germ Juice (www.germjuice.com).
Time: 50 minutes / Thematic Areas: Science, Health, Life Skills
Goal for Learning: Students learn that “clean” hands and/or surfaces may not be so clean after all and discover the critical importance of washing their hands to prevent the spread of disease.
Materials: Pens/crayons and paper / Gel that simulates the presence of germs on students’ hands / UV light / Place for washing hands with soap (sink, basin, or other) / Towels
1 Ask students, “How do you think germs are spread? If one person has a cold, how can you catch it?”
2 Students will give many answers, such as “If you sit next to them”; “If you drink out of their cup”; and “If they sneeze on you.”
Write these answers down
3 Ask students to develop a chart that will help them score how clean their hands are. Divide a large piece of paper into five sections. Trace the outline of a hand in each section. Now have students use pens or crayons to shade their idea of completely dirty, very dirty, dirty, and slightly dirty hand. Label the completely dirty hand as ++++, the very dirty hand as +++, and so on. Use a minus sign (−) to represent the “completely clean” hand. 4 Spread some of the germ-simulating gel, paint, or powder evenly on both of a student’s hands, including the backs of the hands and the skin next to and under the fingernails. Allow the material to dry completely on the student’s hands (this should take a minute or two). Then place the student’s hands under the UV light.
Under the light, the “germs” will show up. Have other students use the chart to determine the cleanliness of the student’s hands that are covered in germs 6 Have the student wash her or his hands for 5 seconds. Stop and check the cleanliness of the hands under the light. Record this as “5 seconds.” 7 Have the student wash her or his hands for an additional 5 seconds. Stop and check under the light. Record this as “10 seconds.” 8 Repeat the procedure two more times, for 15 and 20 seconds. Each time, have students record the level of cleanliness. 9. Change roles and repeat the activity until everyone has had a turn being the hand washer.
Optional Extension: 9 If gels and UV lights are not available, you can substitute either a nontoxic, water-soluble children’s paint or a mixture of vegetable oil, baking flour, and food coloring. In this case, one student will smear the paint or mixture on her or his hands, then shake hands with the group, and all can check their hands to see how the “dirt” travels from one person to another