Kids enjoy investigating scientific principles themselves rather than just reading about the concepts in a textbook. Help students in your class fully comprehend the topics by providing them with fun activities in which they can figure out how things work together. Depending upon the complexity of the subject, you may have to demonstrate the activity for your students, or they may be able to perform the investigation themselves.
Demonstrate surface tension by filling a bowl with water and setting a few matchsticks on the surface of the water. Place a few drops of liquid dish soap in the center of the bowl and watch as the matchsticks quickly dart to the edges of the bowl. As the soap hits the water, it gives off an oily film, which breaks the surface tension and pushes the matches outward.
Investigate the strength of magnets by letting kids see if the can pick up different minerals, such as hematite, magnetite, franklinite, chromite, ilmenite and pyrrhotite. Hold a strong magnet over a pebble-sized mineral and see if it is attracted to the magnet. Record which minerals jumped toward the magnet and which stayed in place. Move the magnet closer and closer to the mineral and even touch the magnet to the mineral to see if it is eventually attracted. Review your findings and research to see which minerals had the greatest amount of nickel or iron in them.
Help students understand about refraction and how light bends through water with some common household supplies. Secure a penny to the bottom of a plastic bowl with piece of putty or tack. Cover the penny with water and push the bowl back until you can't see the coin in the bowl. Slowly add more water to the bowl and watch as the coin appears to move in the bowl. The coin appears to rise in the bowl because light bends in the water and makes the coin appear to be closer to the surface than it really is.
While eggs normally sink in water, you can make an egg float by changing the density of the water. Fill a drinking glass halfway full of water and place a brown egg in the water to show how the egg sinks. Remove the egg from the water with a spoon, then mix in about 6 tablespoons of salt to the water. Lower the egg into the water again and watch as the egg floats to the surface of the water. Saltwater is denser than regular water, which makes it easier for things to float in the water. Retest the experiment by gently pouring the salt into the water without mixing it up; you should see the egg float in the middle of the water in between the salt on the bottom and the surface of the water. Although you can use a white egg for this experiment, it's easier to see brown eggs in milky-white water.