Aspirin? How can that Demonstrate Digestion?

This week in my class is all about digestion. Yesterday student did an activity about the mouth, saliva, and amylase. They chewed up a soda cracker, into a bolus, and held it on their tongue for 2 minutes until it tasted sweet. As a class we discussed how the salivary glands secrete saliva which has the enzyme that triggers this-large complex carbohydrates to be broken down into simple sugars. So the class said, "digestion begins in the mouth."

Today Students used one cup of vinegar (represented HCL in the stomach) and a second cup of water, baking soda ans salt (represented the small intestine). I provided each group two aspirin one un-coated, and one coated. They placed both aspirin in the vinegar simultaneously and waited for two minutes making observations. The un-coated on dissolved quickly while the coated one lost its coating but remained in tact. This demonstrated that the stomach does not break down everything entirely.

Then students took the remaining aspirin and placed it in the baking soda water. There was a slight foaming due to the vinegar, it floated for a second, and more of the coating began to deteriorate. Finally, they waited for fifteen minutes, again documenting observations. During the 15 minute wait time, students drew mini-posters of the three types of energy transformation in digestion: Chemical to Chemical, Chemical to Thermal, and Chemical to Mechanical. After fifteen minutes they stirred the water mixture to determine how much of the aspirin was left. Most of it was left. As a class we discussed how the coating, like nutrients was absorbed in the water, like the villi in the small intestine. The remaining aspirin was what would be considered waste and would be passed along into the large intestine.

Today was an engaging lesson that took students one step further into the digestive tract. Tomorrow we are going to demonstrate all the organs in the digestive tract from mouth to anus using various materials, Ziploc, bread and OJ, panty hose, and even the mouth of a non-latex balloon. Can you determine which materials represent which organs? That is what students get to tackle tomorrow.