Materials Required:
1 banana
6-8 crackers
1-2 tablespoons lemon juice or clear vinegar
Ziploc plastic bag
Old pair of tights or stockings
Plastic funnel
2 paper or Styrofoam cups
Gloves
Scissors
Tray or container to contain the mess
Sharpie (optional, to label the different parts)
Steps Involved:
Begin by showing the students a banana and the crackers. Ask them what happens when we eat food, guiding them to understand that food goes through the mouth, reaches the stomach, travels through the intestines, and is eventually eliminated as waste.
Explain that during digestion, the food changes color, texture, and even smell because the body absorbs the nutrients, leaving only the waste to be expelled.
Start the experiment by cutting the banana into small pieces and crushing the crackers.
Place the banana and crushed crackers into a Ziploc bag. Add 1-2 tablespoons of lemon juice or vinegar to simulate stomach acid.
Seal the bag and gently knead it to mimic the mechanical breakdown of food in the stomach. Discuss how the food is being broken down into a liquidy mixture.
Cut a small hole in the bottom of the bag and let the mixture pour through a funnel into a pair of tights or stockings. This simulates the food moving through the intestines.
Squeeze the tights or stockings gently, representing the absorption process as the food moves through the small intestine, with nutrients being absorbed into the body.
Cut another small hole at the end of the tights, letting the remaining mixture fall into a cup. This represents the elimination process, where the remaining waste exits the body.
Discuss how the food’s appearance has changed throughout the process, emphasizing how the body absorbs nutrients and eliminates waste.