Sample Experiment Write-Up – Done as a class the week of Sept 17-21

Question: Which brand of diet cola will make the largest fountain when Mentos are added?

Hypothesis: If I add Mentos to brand name and store brand diet cola, then brand name Diet Coke will make the highest fountain.

Materials:

  • 1 2L bottle of Diet Coke
  • 1 2L bottle of store brand diet cola (we used Western Family)
  • 2 regular packages of mint Mentos
  • 2 measuring tapes
  • 2 sheets of paper
  • Tape
  • Video Camera (optional, but it helped to be able to refer back to the tape when recording data)

Variables: I can identify the following variables in my experiment:

  • Manipulated Variable: The brand of cola
  • Responding Variable: The height of fountain
  • Controlled Variables:
  • Number of Mentos dropped into the cola
  • Same flavor of Mentos
  • The amount of pop in each test
  • Temperature of the cola

Procedure:

1.)Gather all materials

2.)Find outdoor experiment site

3.)Tape measuring tapes to wall or post

4.)Set down the first bottle near measuring tape

5.)Take the lid off the bottle

6.)Take all Mentos out of packages and roll all the Mentos loosely in piece of paper

7.)Hold Mentos paper roll over pop bottle opening and release

8.)Stand back and observe the height of the fountain, record

9.)Repeat steps 4-8 with the second bottle of pop

10.)Analyze data and record conclusions

Data:

Diet cola (store brand) / Diet Coke
Height of fountain / 142 cm / 319 cm

Conclusion:

My hypothesis was correct because the brand name Diet Coke produced the largest fountain when we added the Mentos. We tried our experiment only once with each type of pop.

The variable I was testing was the height of the cola fountain. Variables I controlled in the experiment included the amount of cola used, the pop’s temperature, the type of Mentos and the experiment location. Variables I could not control included the bottle shape and the number of Mentos that actually dissolved in the cola. I could not control these variables because the store brand pop automatically had a different bottle shape and some of the Mentos slipped or popped straight out of the cola bottles.

(this paragraph talks about what went wrong or other reasons why you might have got the results you did) A few more attempts at this experiment might give us a better idea of which pop would consistently make the highest fountain. We believe that the Diet Coke could have made the biggest fountain just because of the bottle shape or the fact that more Mentos were able to dissolve. We also had to guess a little at the biggest fountain’s height because it went beyond the measuring tapes.

On concept this experiment taught us was that cola and Mentos produce a chemical reaction. Another thing we learned was that a cola fountain is huge! If you are repeating this experiment make sure everyone stands clear.