The procedure of making bottle rockets at home is quite easy. One can make a good working models by using easily available materials, such as bottle, duct tapes, straws, etc. This activity can also be used as one of the team games in schools. Kids at home can take the help of adults during the building process, and have a good time in making them fly! What is a Bottle Rocket? It is a toy, which works by the application of air pressure. Such rockets are made by children for school competitions, or just as a pastime activity. One can experiment a lot regarding the designing and functioning of such rockets. By making variations in the air pressure and quantity of water to be filled in the bottle, several experiments regarding the working mechanism can be undertaken. How to Make a 2 Liter Bottle Rocket? One need not buy expensive materials for this activity, and easily available and cheap materials can also be used. Materials Needed A 2 liter bottle, duct tape, paper, straws, bicycle tire pump, rubber stopper, needle, a metal rod (¼ inch) ,and decorative items (crayons, scissors, etc.). Needle, bicycle pump, and stopper form the components of the propulsion system. Procedure The rubber stopper should be drilled to form a tiny hole for the needle to pass through. The hole should be around 1/16^th inches in diameter. The needle should then be inserted through the stopper into the bottle. Duct tape needs to be used in order to fix the straw pieces to the bottle. Care should be taken to see that these pieces are taped properly, i.e., in a straight line. Children like to add more decorations to the rocket, apart from these components. The model's design includes fins to be attached at the base, and a nose at the top of the bottle. A cardboard/poster board can be used to make the fins. Triangle-shaped pieces cut from the cardboard should be taped at the rocket base. The nose can be made by cutting the cardboard in a circular shape, which needs to be rolled into a cone and taped at the bottle's top. The nose and fins can be colored to make them look attractive. Launching The bottle rockets should be filled up to ¼ - ¾ of their capacities. Mouth of the bottle need to be corked tightly with the help of a stopper. A needle is connected to the pump, and then the bottle is placed over a metal rod. Once it is properly mounted, the process of pumping is started. Pressure in the bottle starts increasing, and at one point, the rocket takes off, leaving a trail of water behind it. The height that can be attained by such models is around 60 feet. One should not stay in the line of launching, as he/she can get injured due to the tremendous pumping pressure. Children can add fun elements to this activity by using various tricks. One could arrange a night rocket launch party. The models can be taped with chemical light sticks. As they rise above in the sky, one can enjoy the sight of light sticks attached to the bottle. Parachutes can be attached to the rockets, which open on their way back to the ground. Warning: Always undertake the above-described activity under the supervision of an adult. During launching, make sure that an adult is handling the pumping process.