Last week we did an experiment using two crackers, water, iodine, and spit. With our partners, using a graduated cylinder, we poured thirty milliliters of water into two separate beakers. Then, we crushed up a cracker and put it into one of the beakers. We added three drops of iodine to the mixture, and it turned purple. For the second cracker, I had to chew it up for three minutes straight. It was very disgusting. For the first half of chewing it up, I had to try hard not to swallow it. But, after two minutes had passed, I had to focus even harder on not gagging and spitting it out. After three minutes had finally passed, I spit out the cracker into the second beaker. When we added the iodine to it, it didn’t turn purple. Instead, it stayed the same color. The reason that the chewed up cracker didn’t turn purple while the crushed up one did is because iodine turns purple in the presence of starch. The crushed up cracker had plenty of starch in it, but when I chewed up the other cracker, my spit dissolved the starch inside of it.
Doing this lab, I learned that spit doesn’t just mush up your food, it also dissolves certain ingredients found in different foods, like starch. I also learned that iodine and starch turn purple when they are mixed together. I was surprised by a few different things when we did this lab. One of them was how quickly the spit dissolved the starch. Another thing was how disgusting it was to chew a cracker for three minutes straight. Even though it was disgusting, it was very cool to watch two of the same type of crackers react completely differently in the same mixture with the only difference between them being one of them was chewed up while the other was crushed. I think that I participated a lot in this lab, and that maybe next time I would like to participate a little less. One thing that I would have done differently during this lab would be making my partner chew up the cracker instead of me having to do it.
Does spit dissolve anything else besides starch? How does spit dissolve the starch? What would happen if you just ate a spoonful of starch?
Dear Savannah,
I liked how you described chewing the cracker and how you showed us your amazement in how the liquid turned purple. You really turned something like chewing crackers into an interesting document about spit dissolving starch. What sort of cracker were you using in the experiment?
Sincerely,
Alex B Stillwell
We were eating saltines
Great post Savannah. There is an enzyme in your spit that dissolves the starch called pytalin. There are others enzymes as well that start the process of digestion. I liked how you noted how different the two crackers were after you chewed. Yes this is disgusting but very visual!