When I met the class way back in September and told them I would be teaching them science, I had requests right away from a few students to do the infamous diet coke and mentos experiment. I promised them that we would do it some time this year and today was the day.
Five students knew what to expect but the others didn't. They were a little surprised! For the first go, we used a geyser tube which is a plastic contraption made specifically for this experiment. It produces excellent results! I asked the students what they thought had happened...we had suggestions of the gravity of the mentos being pulled down causing it, the mint of the candy being the cause, the chemicals in the pop or as one student was sure of, it must have been a chemical reaction like our alka seltzer rocket experiment. I explained, in grade 3 type language, the physical reaction that actually occurs (based on my years of researching this with my own sons!).
For the next go, I asked students to specifically observe what was happening in the bottle, above the bottle and to estimate how high the expulsion reached. We used a metre stick held up by a student as a referent and our highest expulsion reached about 4.5 metres.
We also tried a more "homemade" device by rolling up a tube of construction paper to hold the mentos in and using an index card to cover the top of the bottle with the tube of mentos above it. A student held the card for me, pulled it and I yelled "run"! I got diet coked, much to the amusement of the students!
We compared results and the students understood how our homemade device could cause "failure" in so many ways and had ideas for improvements. A colleague of mine dropped by to see what was going on and wondered aloud to the students what might happen with different kinds of candies. Oh, that got their minds going with all sorts of ideas!
Comments