Icky Sticky Fingers-Final Thoughts

We ran the Icky Sticky Fingers experiment 4 times using 4 different mediums (regular ol' wheat bread, preservative free wheat bread, homemade nutrient agar, and cheap ol' white bread). The results were somewhat surprising and as an added bonus, I now have a 2 year old and a 3 year old who are very good at washing their hands...no more nagging from me!

Let's go over the results, shall we?

Icky Sticky #1

Plain ol' wheat bread...nothing special, except that IT NEVER MOLDED! Well, at least not in the 17 days I had it out in the garage. This stuff has some serious shelf life! I wouldn't try this one in the classroom because of the time needed. Even though kids are learning about patience, theirs might just run out (and yours too) during this experiment with this type of bread.

Icky Sticky #2

Preservative free wheat bread. It got moldy really fast (about 3 days), which is great in terms of classroom time, however the results weren't very reliable. My control (which was not touched) grew the most mold and Charlie's clean bread sample grew more mold than his dirty bread sample. This experiment might yield better results if the kids had washed their hands better (but let's face it, sometimes getting a 2 and 3 year old wash their hands at all is a major feat in itself). 

Icky Sticky #3

This was, by far, my favorite experiment. The nutrient agar turned out great and it introduced the kids to equipment and terms used by scientists in the field. The petri dishes sat in our laundry room for about a week (~78 degrees Fahrenheit) and produced some of the best results. Did I mention that there was no odor? The kids were very excited about this experiment and when it was all done, they were a cinch to clean up (yes!). 

I'll post the nutrient agar recipe below with a list of supplies and where they can be purchased. I would highly recommend this experiment for your students! It's cheap, easy, and yields great results. You can't ask for more than that!

Nutrient agar recipe: click HERE

Materials needed for nutrient agar: 

• Beef broth (bullion cubes, canned, or granules), water (unless using canned, prepared broth as I did), unflavored gelatin, and sugar.

Petri dishes (size 100 x 15mm): 

• Amazon: $9.95/20 petri dishes (click HERE)  
• Seargent Welch (accepts P.O.'s): $8.95/20 petri dishes (click HERE)

Possible alternative petri dishes: foil cupcake cups placed them in a zippered baggie for storage during the incubation time. I've never done this before, but I'd love to hear how it worked out for you.

Each student will need two petri dishes (one clean and one dirty), however, it is possible to have students do this in pairs where they both touch one petri dish with their dirty hands and then both touch a second petri dish with their clean hands. It's a cheaper alternative. :)

Icky Sticky #4

This was another great experiment that yielded some really good results in a short amount of time. Additionally, it was cheap, which is always a plus for teachers. I would definitely recommend this one for a classroom.

Icky Sticky Fingers Mini Unit: Almost done! Keep checking back if you're interested in it!