The common belief was that three states of matter exist: gas, liquid and solid. However, a fourth state of matter exists called plasma. Plasma is an ionised gas whose electrons are free. It is by far the most common state of matter in the known universe, making it the ideal subject for many physical science-related science fair projects.
Plasma Sphere and a Light Bulb
Plasma spheres are controlled by a Tesla Coil inside the centre. This kicks off an electromagnetic field that can cause gases to glow. Fluorescent light bulbs contain gases that will be activated by the energy of the plasma ball. Be sure you choose a fluorescent bulb, as those are the only ones with the correct gases for this experiment. To demonstrate this, hover a fluorescent light bulb close to the plasma sphere. Your light bulb should begin to glow. To demonstrate how a circuit works for a plasma science fair project, you will need a plasma sphere, a fluorescent light bulb and a friend. Have your friend keep a firm grip on the plasma sphere with one hand, while holding the light bulb in his other hand. Hold your hand on the other end of the light bulb and watch it glow.
Lightning as Plasma
Lightning could be called "Earth plasma." This is because when lightning strikes it ionises the air around it and turns into plasma, which is the light you see. You can demonstrate plasma in action by creating lightning in a pan. Adult supervision is advised for this science project. Press a metal thumbtack through the centre of an aluminium pie pan. Then stick a ballpoint pen on the tack and hold in place with hot glue. Rub a wool sock onto a piece of polystyrene. This will cause the polystyrene to become negatively charged. Pick up the pan by the pen and place it on the polystyrene. Hover your finger close to the pie plate. This should cause you to see and hear a tiny spark. Be careful not to actually touch the pan with your hands. Turn out the lights to get the full effect.
Solar Wind as Plasma
As part of a science fair project, you could research how solar winds strike the earth. Solar winds are simply plasma shot off by the sun. As the stream of charged particles leaves the upper atmosphere of the sun, magnetic fields are created which move through the solar system. Scientists use magnetometers to measure these magnetic fields. Use these instruments to measure these solar winds in the atmosphere. Magnetometers are available for purchase and would make useful instruments for a more advanced science project. However, if one is not available, students could write a research project explaining how magnetometers work and possible explanations for the variations in magnetic fields. Students can also examine how organisations like NASA use magnetometers in their research.