What effect does the size of food have on the rate of digestion?
(To chew or not to chew) Use safety goggles. Ask students the importance of the size of particles on digestion. Tell them we will be using a piece of chalk and acid to simulate the effect of digestive juices on different size particles. Step 1 Students are to take the piece of chalk and break it into three equal pieces. Piece one is left whole, piece two is crushed with a mortar and pestle into smaller particles, piece three is crushed in with a mortar and pestle into a powder. Step 2. Using a balance, place equal masses into three 250 ml beakers. Step 3. Measure 100 ml of acid, and place it into the first beaker. Time the reaction. Do this with each of the other two beakers. Step 4. Make a bar graph and compare the results. How does the rate of the reaction compare to the size of the particles? Why is it important that we chew our food? Activiy 2: Why does an unsweetened cracker taste sweet after two minutes? Step 1. Use safety goggles. When you performed the previewing activity, you
