Experiment 15 — Wake Up the Yeast

Topic: Biology · Class 8 · Microorganisms: friend and foe

Aim: Inflate the balloon on the bottle using yeast.

Daily: This is how every bhatura, dosa batter, idli and loaf of bread rises, and how curd sets from milk. Microorganisms are not all enemies — many of them feed us.

Question: Yeast is boiled before being added to warm sugar solution. What will happen?

Exp: Only living yeast can ferment sugar. The boiled sample is the control.

Question: Yeast produces which gas during fermentation?

Exp: The trapped gas makes dough rise.

Question: Curd is set from milk by…

Question: Antibiotics are useless against…

Exp: Which is why they should not be taken for a common cold.

Exp: It kills most microbes without spoiling the milk.