Equipment: The equipment includes...
- sausage balloons;
- pegs?
- nylon wire (about 6-10 metres: to reach across your classroom);
- a drinking straw;
- masking tape.
Method: Inflate a sausage balloon and hold the end (or peg it shut). Masking tape around the two ends of the drinking straw down onto the top of the balloon. Tie one end of a 6-10 metre nylon thread about 2 metres up on one wall in the classroom and hold the other end on the other side of the room so that the thread is horizontal. Place the straw of the balloon through the unattached nylon thread and release the balloon and peg.
Background knowledge: The air inside the balloon is under greater air pressure than the surrounding air. When the balloon is released the elastic energy in the balloon pressing down on the air inside can then escape out the back end. Fast moving air particles at the nossle end collide with stationary air particles out the back end of the balloon. These millions of collisions create the thrust for the air balloon to propel forward along the thread.