Digestion and cat food
The materials required for the experiment are as follows:
- 150g of 4 brands of cat food (IAMS, Friskies, Pet Promise and Nutro Natural Dry)
- 1200ml of hydrochloric acid
- a large beaker
- pH paper
- 4 beakers
- 1 measuring cylinder
- 1200ml of meat tenderizer
- tap water
- a digital weighing scale
- a strainer
- a black marker pen
1. For this science fair project, the independent variable is the brand of cat food (IAMS, Friskies, Pet Promise and Nutro Natural Dry). The dependent variable is the amount of food that is digested by the cat. The constants (control variables) are the amount of cat food that the cat is fed, the pH level of hydrochloric acid, the amount of acid used, and the amount of meat tenderizer used.
2. Label the4 beakers according to the cat food brands: IAMS, Friskies, Pet Promise and Nutro Natural Dry.
3. Pour hydrochloric acid into a larger beaker and mix it with water until the mixture is of the pH level 2. This acid solution is to simulate the acidity inside a cat’s stomach. Using a measuring cylinder, pour 300ml of the acid solution into each of the 4 beakers.
4. Place about 150grams of each brand of cat food in the beakers, according to their labels. Put the 4 beakers aside for the next 12 hours. By then, the protein that is in the cat food should have been softened and denatured by the acid.
5. After 12 hours, drain the hydrochloric acid using a strainer. Pour 300ml of meat tenderizer into each beaker. The meat tenderizer contains enzymes that are similar to those found in a cat’s small intestine. Put the 4 beakers aside for the next 12 hours. By then, the protein that is in the cat food should have been reduced to amino acids.
6. After 12 hours, strain the meat tenderizer from the beakers. Allow the residue in the beakers to dry for a day. Weight whatever cat food is left – this weight will represent the weight of the cat’s feces. Measure it using a digital weighing scale and record this weight in the table below.
7. Calculate the percentage of digested food with this formula:
% food digested = (Start weight – Final weight)/ Start weight x 100%
Be carefuly when handling acid.