Bring ‘active dry yeast’ from the market. Mix a spoonful of yeast, two poonfuls sugar with «sufficient quantity of lukewarm water in a bottle. Fix a colourless, transparent balloon on the mouth of that bottle.
Take a drop of the solution from the bottle on a glass slide, put a cover -slip over it and observe it under the compound microscope. Store the solution in the bottle carefully.

Bring ‘active dry yeast’ from the market. Mix a spoonful of yeast, two poonfuls sugar with «sufficient quantity of lukewarm water in a bottle. Fix a colourless, transparent balloon on the mouth of that bottle. Find out how to use the solution prepared in the above experiment, to make bread. Follow the recipe and make the bread. Find out and note down the reasons why the dough rises and makes the bread spongy.

Bring 'active dry yeast' from the market. Mix a spoonful of yeast, two spoonful sugar with a sufficient quantity of lukewarm water in a bottle. Fix a colourless, transparent balloon on the mouth of that bottle. What changes do you observe after 10 minutes? Mix limewater with the gas accumulated in the balloon. Collect that lime water in a beaker and observe it. What do you notice?

Search for a pond with greenish water. Collect some of the green fibres from the water. Put the fibres in a petridish and wash them clean with water. Put one of the fibres in a drop of water on a glass slide and spread it out straight. Put a cover-slip over the slide and observe under a compound microscope.

Activity 2 : Bring the active dry yeast powder from market . Take 50ml lukewarm water in a conical flask. Add 5gm of active dry yeast powder and 10 gm table sugar to that water andmix the mixture well. Keep the flask in warm place and after an hour take a drop of that mixture on a clean glass slide. Put a cover-glass on that drop and observe it under the compound microscope.

Activity 1 : Take a conical flask and collect the water in it from a pond having stagnent water and aquatic plants. Add some wheat grans and aquatic plants to it. Keep it for 3-4 days so that wheat grains and plants will decompose. Early in the morning on fourth day, take a glass slide and put a drop of that water over it. Carefully, put a cover-slip on that drop and observe under compound microscope.

Apparatus: Two plastic bottles, measuring cylinder, thermometer, etc Chemicals: Potassium nitrate, sodium hydroxide, water, etc. (Sodium hydroxide being corrosive, handle it carefully in presence of teacher.) Procedure: Take I 00 mL water in each of the two plastic bottles. Plastic being insulator of heat, the dissipation of heat can be prevented. Note the temperature of water in the bottles. Put 5 g potassium nitrate (KNO_3) in the bottle and shake well. Note the temperature of the solution formed. Put 5 g sodium hydroxide (NaOH) in the other bottle. Shake the bottle well. Note the temperature. In the first bottle, the process of dissolution of potassium nitrate took place while in the second bottle, the process of dissolution of sodium hydroxide took place As per your observation which one is exothermic process and which is an endothermic process?