A magnetorheological fluid is a liquid that hardens near a magnet, and becomes liquid again when you remove the magnet. They are simple to make in your kitchen after a trip to a sandbox.
http://sci-toys.com/scitoys/scitoys/magnets/magnets.html#rheological
Investigate the performance of batteries in a scientifically valid way.
http://www.sciencebuddies.com/mentoring/project_ideas/Elec_p008.shtml
Which battery lasts the longest out of four different brands, Duracell, Energizer, Eveready and Rayovac?
http://www.energyquest.ca.gov/projects/battery.html
In this experiment, students will make observations of a coupled oscillator.
http://www.pasco.com/experiments/physics/may_2003/home.html
An easy attractive project make an electromagnet using a nail and some battery.
http://www.energyquest.ca.gov/projects/electromagnet.html
It is fairly easy to build an electromagnet. All you need to do is wrap some insulated copper wire around an iron core.
http://education.jlab.org/qa/electromagnet.html
Students will use a Magnetic Field Sensor to discover the characteristics of fields around magnetized materials.
http://www.pasco.com/experiments/physics/april_2002/home.html
Find out how lightning works in a storm by safely creating mini-lighting bolts.
http://www.energyquest.ca.gov/projects/lightning.html
A small device that controls the voltage flow by a dial or knob.
http://www.energyquest.ca.gov/projects/rheostat.html
In this experiment, students will use a current and voltage sensor to discover the relationship between the voltage and current in a DC circuit.
http://www.pasco.com/experiments/physics/april_2001/home.html