Busy Little Scientists

Remember how I used petri dishes for one of the Icky Sticky Fingers experiments? I loved them because they got my kids really excited about the experiment. Yesterday I opened the freezer to find one of the shelves covered in petri dishes that contained an assortment of materials. My 3 year old son came running around the corner frantically telling me to close the freezer. I asked him what he was doing and he replied, "I'm doing really cool experiments, Momma!" Needless to say, I am one happy "Momma" right now as I watch my kids explore the world around them. I'm a big advocate for getting science equipment into the classrooms because kids get so excited about it and what they are going to learn with it. Let me know how I can help you do this!

Charlie's experiment consisted of seeing what would happen to water, sand, rocks, leaves, water with paint in it, and grass if he put them in the freezer. 

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!

Icky Sticky #4 UPDATE

WooHoo! It worked! The experiment done on a cheap loaf of white bread worked the best (well, at least out of the experiments that were done on bread). I got pretty good results within a week, which is also good in terms of having an experiment performed within a reasonable amount of time in a classroom setting (we don't want those kiddos getting bored!).

What helped get the results we were after? 

• I got Charlie's hands *really* dirty out in our planter beds. 
• I put the bread in the garage to incubate. It was pretty warm out there (around 90-100 degrees Fahrenheit). Typical classroom temperatures should work well too.

Almost Done!

As I've mentioned before in an earlier post, my mom and I have been working on the Icky Sticky Fingers mini-unit for healthy habits. It's almost done and contains worksheets for several primary grade levels, including both bread and petri dishes experiments, as well as a poem and a craftivity for students to do. I'll have it up on my Teachers Pay Teachers soon, keep checking back for updates!

Icky Sticky Fingers #3 UPDATE

I am seriously excited about this experiment. I love the fact that we used a nutrient agar and petri dishes (it's so sciencey and introduces young kids to the science equipment that scientists use all of the time). I'm also loving this experiment because of the awesome results that I am getting. Check out the collage below!

The top pictures show the clean hand petri dishes, while the bottom pictures show the dirty hand petri dishes. All petri dishes, except for the control, have bacterial growth on them, but the dirty hand petri dishes have much more. I could look at those petri dishes forever; they are absolutely fascinating. The dirty ones have formed this film on the top that resembles plastic wrap. All of the agar is now liquified (except for the control) due to bacterial growth (and what's even better, there is no smell). This is such a great turn out, especially after the trouble I experienced in the beginning (all I had to do was move them inside to a slightly cooler spot, yet warm enough for bacterial growth). Total amount of time needed for this type of bacterial growth: 3 DAYS!!! Fast, cheap, and great results...three elements of a successful classroom experiment. 

Icky Sticky Fingers #4

Alright, here we go again, for a fourth time. This time I am going to run the same exact experiment with plain ol' cheap white bread. I also made sure that Charlie went and got his hands good and dirty in our planters. We'll see how long this one takes. Updates coming soon!