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        I don't know how they did the activity 
but we prototyped this as an exhibit years ago. 
You have to have a way of visualizing the 
bacteria on your hand before and after the 
"washing". We did it with agar containing petri 
dishes but it takes a a day or so to culture the 
microorganisms on your hand this way. There maybe 
harmless dyes that you can use so this can become 
a program.

If you use soap and water the effect is not so 
great; microorganisms sequester themselves in the 
creases and crevices of your skin. In fact 
surgeons who use strong bactericidal soaps and 
vigorous brushing still use sterile gloves as a 
physical barrier.

I would be very careful about the message you are 
conveying so that you don't play into the fears 
that folks have about "germs". In the context  of 
growing on your skin the microbes are not 
dangerous. The skin is a good physical  barrier 
and many bacteria on skin keep other more harmful 
bacteria from gaining a food hold. The second 
barrier is our immune system that is very 
effective against many, many microorganisms if 
they penetrate the skin though an abrasion or 
cut. Another point I would suggest to make is 
that of the huge number of microorganisms that we 
know about and the greater number that we do not 
know about only about 1% are harmful. The rest 
are beneficial or benign. In fact many bacteria 
in side us are essential to are well being. Grem 
free animals do not survive well. So I think you 
need to put the bacteria that live on our skin 
into perspective.

Let me know if you need any more information or help.
>
>Greetings,
>
>A few years ago at the ASTC Conference some educators presented an activity
>where visitors test regular soap, bleach water, antibacterial soap, and
>antibacterial gel to determine which of these things are effective.  I would
>like to introduce this program into our educational offerings but
>unfortunately I can't remember what the different substances were tested on
>and some of the other logistics needed for carrying out this activity.  If
>anyone has done this or is doing this, I would greatly appreciate a little
>email assistance.  Thanks much.
>
>Eric
>
>Eric Meyer
>Science Educator
>¡explora! Science Center and Children's Museum of Albuquerque
>2100 Louisiana NE #98
>Albuquerque, NM 87110
>505-842-1537 ext. 21
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>
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