Ask the pupils to predict what will happen when you push slowly on the stick. Hit the stick sharply. This is an easy enjoyable set of activities that are rich in physics concepts. The materials include a series of clear plastic soda bottles with various fluids and fixtures that demonstrate eight different physical effects. All demonstrations can be easily built with recycled or dime-store components.
Students whirl the bottles to start a vortex.
Similar to above, but with straw-like tubes up and down. When bottles are turned over, a fountain spray results. Because the volume in the lower bottle is fixed and air takes up space, the liquid has nowhere to go but up. An eye dropper in a bottle of water. Students squeeze the bottle to make the eye dropper sink.