Caught Dirty Handed

Why is hand washing important?
When was the last time you washed your hands? Did you use soap? What have you done since you washed? Have you eaten, put your fingers in your mouth or touched someone else? 
Observations in public restrooms have revealed that only about 68 percent of Americans wash up before leaving. Yet thorough hand washing is one of the best ways to prevent the spread of infections. 
You carry millions of microbes on your hands. Most are naturally occurring and harmless, but you can pick up some that cause illnesses, such as colds, flu, and diarrhea. 
When we forget to wash our hands, or don't wash them properly, we can spread these germs to other people, or give them to ourselves by touching our eyes, mouths, noses or cuts on our bodies. 
We can also pick up germs from objects, such as doorknobs and stair railings, touched by other people who aren't good hand washers. Think about all the things you touch each day and how many people may have touched them before you. 
Hand washing with warm water and soap can greatly reduce the chances of spreading or getting germs. The mechanical action of scrubbing loosens up the dirt and microbes on our hands and the soap picks them up and binds to them so that the water can wash them away.
In this group activity, you and your lab partner(s) will test the effectiveness of different hand washing times, techniques and materials.

You’ll need:
•	Timer or watch that counts seconds 
•	Sink 
•	Blindfold 
•	Washable paint
 	
© Eric MacDicken
•	Paper towels 
•	Hand soap  
What to do:
1. Use the following scoring guide for hand cleanliness.  The completely dirty hand is ++++, the very dirty hand is +++, and so on.  Note that – stands for completely clean. 
	 
© Eric MacDicken

2. Pick one person to be the hand washer and one person to be the timekeeper.  The washer should put a small amount of washable paint on the palm of one hand and spread it evenly over both hands, including the backs of the hands and the skin next to and under the fingernails.  Allow hands to dry completely—about a minute or two. 
 	
© Eric MacDicken

3. Go to the sink, and blindfold the hand washer so he or she can’t see his/her hands.  Turn on warm water.  Have the washer wash with just water for one second.  After one second, have the timekeeper blot dry the washer’s hands by very lightly touching the paper towel to the skin (don’t rub!).  Using the scoring guide, record the cleanliness on a scoring chart.  This scoring chart should be labeled "Water Only."  Don’t let the hand washer see his/her hands or give away any hints about how clean they are. 
4. Have the washer wash for four more seconds with just water.  Again, lightly blot the washer’s hands and record their cleanliness. 
5. Have the washer wash for fifteen seconds more with water.  Once again, blot and record the cleanliness. 
6. Take the blindfold off and allow the washer to completely clean his/her hands. 
7. Change roles, and repeat steps 2 through 5, only this time have the washer use soap each time.  Use a new scoring chart labeled "Water and Soap."  
8. Display your results.  Create two graphs showing the average cleanliness score at each time interval.  One graph will show the results when hand washers used water only.  The other graph will show results when they used water and soap.  Put the time on x axis going across the page. Mark every number between 0 and 20 seconds. Put the average cleanliness scores on the y axis. 
Scoring chart:
	Wash Time (in seconds) with Water Only	
Washer Name	0	1	5	20	
					
Class
Average					

	Wash Time (in seconds) with Water and Soap	
Washer Name	0	1	5	20	
					
Class
Average					

Questions
1.	How might hand washing affect your family’s health?
2.	What difference does soap make? 
3.	What infectious diseases could be spread by failure of people to adequately wash their hands?

When You Should Wash
Before you
•	Prepare or eat food 
•	Treat a cut or wound 
•	Tend to someone who's sick 
•	Put in or take out contact lenses 
•	Do any kind of activity that involves putting your fingers in or near your mouth, eyes, etc. 

Microbes found on a cutting board.
(© Dennis Kunkel)
After you
•	Go to the bathroom 
•	Handle uncooked foods, especially raw meat 
•	Eat 
•	Blow your nose, cough or sneeze 
•	Handle garbage 
•	Tend to someone who's sick 
•	Change a diaper 
•	Play with or touch a pet, especially reptiles and exotic animals 
Hand washing is mostly a matter of common sense!  Use it!