3. Complete Activity 2.3 (Page 20). Take ½ kg flour (atta or maida), add some sugar and mix with warm water. Add a small amount of yeast powder and knead to make a soft dough. What do you observe after two hours? Did you find the dough rising?
Answer: The above activity can be carried out as follows:
Aim: To observe what happens to the dough after two hours and make the necessary conclusions.
Materials Required: ½ kg maida, sugar, warm water, yeast powder, bowl.
Procedure:
(i) Take ½ kg maida in the bowl, add some sugar and mix with warm water.
(ii) Add a small amount of yeast powder and knead to make a soft dough. Let the mixture sit for two hours and observe what happens.
Observations:
You will observe that after two hours the dough rises.
Conclusions: We conclude that the dough rises because of the presence of yeast in the mixture. Yeast produces carbon dioxide during respiration. Bubbles of the gas fill the dough and increases its volume.
“Take ½ kg flour (atta or maida), add some sugar and mix with warm water. Add a small amount of yeast powder and knead to make a soft dough. What do you observe after two hours? Did you find the dough rising?” – Solved.
Related Links:
Solution to Extended Learning Problem 1
Solution to Extended Learning Problem 2
Solution to Extended Learning Problem 3
Solution to Extended Learning Problem 4
Solution to Activity 2.1
Solution to Activity 2.2
Solution to Activity 2.4
Solution to Activity 2.5
Solutions to Chapter 2 Microorganisms: Friend and Foe
