Take a prism and discover the different colors of light that make up the white light that is generated by the sun. Shine the refracted light onto a piece of white paper and have students draw the dividing lines between the different colors of the light on the paper. This can help them determine the wavelength of the colors in the rainbow instead of just the colors. This will introduce wavelength and frequency to students.
Display to the students in your class how the angle of the sun's light affects the temperature that is recorded on a thermometer. Set up three large thermometers that are easy to read in a window in the classroom. Set one up at a 45-degree angle, one at a 90-degree angle and one flat on a windowsill. Each day for a week, record the temperatures on the three thermometers. Note which one has the highest temperature each day and discuss why it was different than the others.
Construct a simple car out of wood by nailing four wheelers attached to a small board, with washers between the wheels and wood so the wheels roll freely. Create several tracks that are the same angle for the car to roll down. The first one should be a wooden track. The second track should be covered with sand glued onto the track. Glue grass to the third track. Record the speed of the car down each track and discuss how friction reduces the speed of an object.
Conduct a science experiment to determine if tastes are determined by age or gender. Choose 20 students from sixth, seventh and eighth grade to participate in the experiment, half male and half female from each grade. Give each student a cup of Coke and a cup of Pepsi to taste, without revealing which soda is in each cup. Record which soda the student prefers. Chart the results and determine if there are any differences based on grade or gender for which brand. Discuss how sampling is conducted, and what errors can occur in sampling, such as basing results on small test groups.