As you pump in air in a plastic bottle it launches straight up like a ROCKET. To make this BOTTLE ROCKET you need a plastic bottle, cycle pump, rubber cork, pin, cycle ball bearing and 2 different diameters of plastic flexi-tubes. On one tube the ball will sit and not go inside. In the other tube the ball will move freely. Take a rubber cork with a hole – readily available in any science lab. Tight fit 30-cm of the fat flexi-tube in it. Push a paper pin in the tube about 5-cm from the cork. The pin will act as a stopper for the steel ball. Then insert the thin tube with the blue end in the fat tube. The ball will move in the space between the pin and the blue end. This will make a one-way valve. Seal the joint between the two tubes. Insert the other end of the thin tube deep into the bicycle pump hose. Tape the joint to prevent leakage. The main apparatus has been assembled. As you pump you will see the ball moving – like a one-way valve. Air can go from the tube to the cork but not the other way round. Fix a plastic bottle to the cork. Hold only the cork and ask your friend to pump air. On pumping air the bottle will soon take-off and launch itself like a ROCKET. Now, fill quarter of the bottle with water. Once again press fit the cork in the bottle mouth. On filling compressed air in the bottle at some stage it will take off and shoot into air and fall 100-meters away. This is a community experiment and many people can collectively enjoy it. This work is supported by IUCAA (www.iucaa.in) and TATA Trust (http://www.tatatrusts.org/) and (www.tata.com/aboutus/sub_index/Tata-trusts) TATA Trust: Education is one of the key focus areas for Tata Trusts, aiming towards enabling access of quality education to the underprivileged population in India. To facilitate quality in teaching and learning of Science education through workshops, capacity building and resource creation, Tata Trusts have been supporting Muktangan Vigyan Shodhika (MVS), IUCAA's Children’s Science Centre, since inception. To know more about other initiatives of Tata Trusts, please visit www.tatatrusts.org Credits:,Ashok Rupner, Manish Jain, Pradnya Pujari, Shivaji Mane, Jyoti Hiremath, Arvind Gupta, Vidula Mhaiskar Dubbed in Telugu by Sri Prakash Vidyaniketan