Experiment 11 — The Starch Detective

Topic: Biology · Classes 4–5 · Components of food

Aim: Find all three starchy foods on the plate using the iodine test.

Daily: Rice, roti, potato and poha are the energy foods on almost every Indian plate. This simple test — a drop of iodine turning blue-black — is exactly how a laboratory checks for starch.

Question: Iodine is dropped on cooking oil. What will happen?

Exp: The iodine test is specific to starch. Oil is a fat, so there is no colour change.

Question: Iodine turning blue-black shows the presence of…

Exp: It is the standard test for starch.

Question: Which food group gives us most of our energy?

Exp: Carbohydrates are the main energy foods.

Question: Dal, eggs and paneer are rich in…

Exp: Proteins are the body-building foods.

Question: Why also test a food you expect to be negative?

Exp: Controls show that a positive result is meaningful.