Digestion
Digestion is how your body breaks food into tiny pieces small enough to use for energy.
A blender breaks whole fruit into a smooth liquid your body can use. You drop in chunks of apple and banana, and the spinning blades chop them into tiny bits. The thick liquid that comes out passes through a fine strainer, which holds back any large pieces. Only the thin, smooth liquid makes it through to the glass below.
Explaining digestion by grade level
When you eat food, your body has to break it apart. Think about meat sitting in a dark, warm, wet place. Your stomach squeezes it and adds strong juices. Those juices break the food into bits your body can use.
Projects that explore digestion
Digestion relies on acids to break food into pieces small enough for your body to use. When acids meet food, gas can form as a byproduct — and processing may change how much. This experiment grinds fresh, frozen, and canned samples of four foods and places each into a test tube with vinegar to simulate digestion. A balloon stretched over the top captures any gas produced. After eight hours of gentle heat, you measure each balloon's width to see whether processed foods generate more gas than fresh ones.
Digestion breaks food into usable pieces through a sequence of acid and enzyme action — but not all foods break down equally. To simulate a cat's digestive system, each 150-gram sample of four cat food brands soaks in hydrochloric acid at pH 2 for 12 hours, mimicking the stomach. Then it soaks in meat tenderizer for another 12 hours, since the tenderizer contains enzymes similar to those in a cat's small intestine. After drying, you weigh what remains and calculate the percentage digested. IAMS had the highest digestion rate among the four brands, showing that ingredient differences affect how completely food breaks down.
Digestion uses acids to break food into smaller pieces, but how far can a weak acid actually go? This experiment puts that question to a popular test. You place 300 grams each of steak, chicken breast, and salmon into separate bowls filled with Coca-Cola and check the meat daily for five days. After the full soak, none of the three meats dissolve — the Coca-Cola changes their appearance slightly but fails to break them down. The results reveal how well common meats hold up against the acidity in a carbonated soft drink.