Take an empty can. Pour small quantity of water in it. Boil this water for a few minutes until the steam has driven out most of the air. Now close the can with the stopper tightly. Allow it to cool by pouring cold water over it. What do you observe ?

Take two rubber balloons. Fill one with water and blow air into the other. Now prick both balloons with a pin. What do you observe ?

Apparatus: A beaker, potassium permaganate crystals, a burner, water, etc. : Procedure: Take some water in a beaker. Heat the beaker slowly on a gas burner. Drop a few crystals of potassium permaganate into the water. Now watch the water in the beaker carefully. What do you see?

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?

Let’s try this : Take a bar magnet that can be cut with scissors or a knife. Take iron filings on a sheet of paper and place the magnet on it. Most of the iron filings will be seen to stick to its poles. Now cut the magnet into two pieces as shown in the picture and place those pieces on iron filings. Pick up each piece and observe. What do you find ?

Apparatus : Test tube, beakers, burner, etc. Chemicals : Glacial ethanoic acid, ethanol, concentrated sulphuric acid, etc. Procedure : Take 1 mL ethanol and 1 mL glacial ethanoic acid in a test tube. Add a few drops of concentrated sulphuric acid in it. Keeps this test tube in the beaker containing hot water (hot water bath) for five minutes. Then take 20-30 mL water in another beaker, and pour the above reaction mixture in it and smell it. What can you say about the smell of the reaction mixture?

Take three similar vessels . Let us call them A,B and C ( see figure below ) Fill A with hot water and B with cold water . Put some water from A and B in C . Dip you right hand in A and left hand in B , and keep them immersed for 2 to 3 minutes . Now dip both the hands in C .: What do you feel ?:

Take a piece of thin aluminium sheet and dip it in water in a bucket . What do you observe ? Now shape the same piece of aluminium into a small boat and place it on the surface of water . It floats , isn't it ?

Read the paragraph and answer the questions given below : Our atmosphere is getting hotter. more turbulent, and more unpredictable because of the “boiling and churning” effect caused by the heat-trapping greenhouse gases within the upper layers of atmosphere. With increase of carbon, methane, or other greenhouse gas levels in the atmosphere, our local weather and global climate is further agitated, heated, and “boiled”. The green house gases such as water vapour, carbon dioxide, methane, nitrous oxide, and ozone are causing great impact on life on earth. Due to global warming, the glaciers are melting, causing sea level rise, coastal submergence and frequent natural disasters. We have to rethink while taking the development projects and help to protect the existing life forms on the earth before its too late because climate change can exterminate us. What can we do to reverse effects climate change?

Paragraph based Questions : Read the paragraph and answer the, questions given below: Sulphuric acid is present in the acid rain and materials coming out of mines . You know that erosion of metals present in statues, bridges and buildings occurs due to it. Sulphuric acid is a source of energy for some species of bacteria like Acidophilum spp. and Acidobacillus ferrooxidans Hence. these bacteria can control the soil pollution occurring due to acid rain water soluble salts of uranium are present in the wastes produced during electroplating and in effluent released in the environment from the atomic energy Plant. Geobacter convert these salts of uranium into insoluble salts and thereby prevent those salts from mixing with groundwater sources. What kind of pollution do these bacteria control?

A sufficiently long closed organ pipe has a small hole at its bottom . Initially , the pipe is empty . Water is poured into the pipe at a constant rate . The fundamental frequency of the air column in the pipe