Digestion Lab

The past two days, we have conducted a lab using, hydrochloric acid, pepsin, boiled egg whites, and water. In four test tubes, labeled A, B, C, and D, we put in three pieces of egg white. In test tube A, we put 10 mL of pepsin. To test tube B, we added 5 mL of water and 5 mL of pepsin. Next, in test tube C, we added 10 mL of hydrochloric acid. Finally, 5 mL of pepsin and 5 mL of hydrochloric acid were added to test tube D. We then had to observe whether a change happened immediately. In test tubes A and C, there was no immediate reaction, but in test tube B, it turned foggy. In addition, in test tube D, it looked as if the egg was slowly melting or turning mushy, Next, we took a straw and dipped it into each test tube then touched the straw to a piece of blue lithmus paper to see if the paper changed color. In test tubes C and D, the paper turned pink. The other test tubes stayed the same.
The next day, we observed our test tubes to see if they had changed. Test tubes A and C, it looked the same. The egg whites in test tube be looked more delicate so if you were to squish them, they'd mush together. In test tube D, the mixture was foggy and it looked as if the egg whites had dissolved and piled together in a mush at the bottom. Also, we had to dip the straws in the mixture again and place it onto the lithmus paper. Test tubes A and B didn't change the color of the lithmus paper, but test tubes C and D made the paper pink again. This lab showed that our stomach was like test tube D. It was full of enzymes (pepsin) and hydrochloric acid working together to digest the food that we eat.