These science fair projects for 7th grade are perfect for allowing older kids to explore more advanced scientific concepts, like electrolysis and electroplating.
Use some household materials to plate your coins with copper! You can also try copper plating designs onto your coins!
Electrolysis is a way to dissolve bits of metal into acidic liquids like vinegar. When you run electricity through vinegar, the vinegar helps to carry electricity from one side of the circuit to the other. Electroplating is a way to put those little bits of copper onto something else. With just a little electricity, you can use electrolysis and electroplating to plate a quarter with copper. Does that make it look like a penny to you?
Did you know that water is actually a chemical? That’s why we call it H2O–water is made up of the chemical elements, hydrogen and oxygen! What would water look like if you could split water into its two parts? Try out this experiment to find out!
When you hook up the wires, electricity flows in a loop from the battery, down one of the pencils, through the water, then up the other pencil and back to the battery. The electricity actually breaks the water molecules apart into it parts — hydrogen and oxygen! The bubbles you see on the tips of the pencils are the hydrogen and oxygen gas created by this reaction. In fact, hydrogen gas is created at one of the pencils, and oxygen gas is created at the other. This process is called water electrolysis.
Take your paper airplanes to new heights by making a motorized launcher for them.
Paper airplanes work just like regular passenger planes and fighter jets: by redirecting air to keep themselves airborne. As long as a plane is moving quickly, its wings will redirect a lot of air downwards, which generates an equal upwards force (lift). This lift is enough to bear the weight of the plane against the pull of gravity. Your paper airplane launcher is effective because it gives the paper airplanes a lot of speed, and therefore a lot of lift — plenty to keep the planes aloft for lengthy trips around a room (or until they hit something!)
Learn about helicopters by making a rubber band powered flying toy!
The two propellers on your rubber band helicopter are able to fly thanks to the same principles that keep real helicopters aloft. The angled blades of the propellers act like fans when they spin, pulling air from above and blowing the air downwards. This creates enough lift to counter the effect of gravity on the helicopter, pushing it higher and higher into the sky. If you set up your propellers correctly, with opposite blade orientations for each propeller, they should both blow air in the same direction, even though they are spinning in opposite directions… double the propellers means double the lift, and double the flying power!
Harness the power of fizzy candy and soda to inflate a balloon without blowing! This experiment can be repeated many times with different sodas to see how each reacts differently and which creates the biggest balloon.
The fizzy candy that we used was made by mixing up warm, sugary syrup with carbon dioxide gas. As the syrup cooled and hardened into small balls of candy, it trapped little bubbles of carbon dioxide inside. Now, when the candy comes in contact with liquid (in this case the soda), the sugar in the candy dissolves away, and the bubbles of carbon dioxide gas escape and fill up the balloon.