Chemical Change in the Kitchen

Objective: Students will identify and describe evidence of chemical change when heat is applied to food substances.

Engage: Have students close their eyes. Have them imagine a cake baking as you use sensory words to describe such things as the eggs, flour, batter, warm oven, and the smell of the baking cake filling the air.

Explore: 1. Have students observe premeasured containers of water and pancake mix, and record their observations in their journal. The teacher or a student takes pictures of each.
2. After combining the pancake mix and water, have students observe the pancake batter and record their observations. Allow students to smell the batter. Photos are taken of the batter and a student smelling the batter.
3. Pour the batter on a pan on a hotplate and have students record their observations as the pancake is cooking. Have them notice the bubbles, the browning, the smell, and the change in state of matter. Break off a piece of the cooked pancake and observe the inside of the pancake. Photograph the batter bubbling, the browned pancake and the inside of the pancake. Also, photograph a student smelling the cooked pancake.

Explain: Have students explain what evidence of chemical change they observed as the pancake cooked. Point out any misconceptions they may have. This may be a good time to discuss that changing state of matter is not evidence of chemical change. This may also be a good time to point out just because something shows evidence of chemical change does not always mean that a chemical change has taken place. Whenever there is chemical change a new substance is formed.

Elaborate: Students will take a camera home and photograph the different stages of a food substance being cooked by a grownup in their home. They will upload their pictures and save them on a school computer. Then, students will use the pictures to make a slideshow in which they will identify and explain the chemical changes that took place when their food item was being cooked.

Evaluate: Students will use a rubric to self evaluate their slide show. Older students may help the teacher generate a grading rubric.