objective: To show experimentally that carbon dioxide is given out during respiration!
(A) respiration in animals:
material required:
1) freshly prepared clear limewater
2) a test tube
3) a cork with two holes
4) two glass tubings bent at 90 degree
1 fill half of the test tube with freshly prepared clear lime water.
2 fix the glass tubing A and B in the cork.
3 fix the cork in the mouth of the test tube such that the end of the glass tubing A is dipping in lime water.
4 put your mouth at the end of the tube A and exhale out air within with force.
you'll observe as the exhaled air bubbles pass through lime water, it gradually turns lime water milky.

(B) respiration in plants:

materials required:
1) conical flask
2) germinating gram seeds
3)KOH solution
4) small test tube
5) A cork with one hole
6) A glass tubing bent twice at 90 degree
7) A 100cc beaker half filled with water.
1 place about 50 germinating seeds in a conical flask and add a few drops of water to keep them moist.
2 Tie a thread(cotton) to the meck of the small test tube. Pour about 4ml of KOH solution in it and suspend it in the conical flask.
3 close the mouth of conical flask with a cork in which a delivery tube tube is fitted, such that the thread tied to the small test tube is held firmly.
4 place a beaker containing  water under the other end of test tube.
5 apply Vaseline on the cork so as to make the apparatus air tight.
6 leave the apparatus undisturbed for two hours.
after two hours the level of water in the delivery tube rises up as compared to level of water in the beaker.