Physics Projects – DIY Physics Experiments
Science experiments are a great way to introduce children, or the child in all of us, to fundamental scientific principles. Here are some cool physics projects you can do at home.
For each of these experiments, it is a good idea to have an adult supervise the children, always wear safety glasses and, if you are working with fire, have a fire extinguisher handy.
Wow your friends with a fireproof balloon
For this experiment, all you need is a balloon and a candle. Fill the balloon three-quarters full with water and fill it with air by inflating the balloon as far as you can. Tie it up.
Light the candle, then slowly lower the balloon onto it. Behold, the balloon will not burst!
This is due to the incredible ability of water to absorb heat. The water in the balloon disperses the heat generated by the candle and prevents the balloon latex from getting hot enough to break. But, when the water in the balloon can no longer absorb the heat from the candle, the balloon will burst and you will probably get a little wet.
The lava lamp
From your kitchen, get a bottle of vegetable oil, food coloring, salt, and a tall glass or glass jar.
Fill the glass container 2/3 full with water and fill the rest with vegetable oil. Add a little food coloring, then slowly pour a teaspoon of salt into the container. Watch beautiful colored orbs of oil gently fall to the bottom of the container.
At first, the oil will stay at the top of the container because oil is lighter than water. The key to bringing the oil to the bottom is salt, it binds to the oil making it heavier than water. However, once the salt dissolves in the water, the oil will rise to the top of the container. Sensational!
This classic experience takes a few days, but it’s worth it.
You will need distilled water, salt or Epsom salts, a piece of wire or a pipe cleaner, and a glass container. First, heat the distilled water to a point just below boiling. Fill the glass container at least halfway with hot water. Add enough salt or Epsom salts to the water to create a saturated solution (the point where no more salt dissolves in the water) and stir well.
Make a loop in the wire or pipe cleaner and lower the wire into the mixture. Place the container in a warm place and wait. After a few days, you should see spectacular crystals forming on the loop of the wire.
This experiment works because of the change in water temperature, and the solubility, the ability of salt to dissolve. As the water cools, the solubility of the solution decreases and the salt rushes out of solution and onto the wire to form crystals.
Build a Popsicle Stick Catapult
To build this mini catapult, you’ll need at least 10 large popsicle sticks, a bunch of rubber bands, a pair of scissors, and marshmallows for the cannonballs. Marshmallows for cannonballs? What ignominy!
Stack eight Popsicle sticks and hold them together with rubber bands at each end. On the two remaining sticks, use the scissors to make a small notch on each side of the stick. Place them together and use a rubber band to hold the sticks together at the notch.
Then, spread the two sticks slightly apart and slide the pack of eight sticks between them. Stabilize your new catapult with one hand and use your other hand to place a marshmallow on the top stick. Pull it back and release to fire!
You can also attach a plastic spoon with a rubber band to the top stick to make a bucket to hold your cannonballs. The castle walls will fall!
make a prism
You can make a rudimentary prism with just distilled water and clear gelatin. Empty a packet of gelatin into a saucepan and add only half the amount of water indicated in the instructions on the gelatin package.
Place the pan on the stove and as it heats up, gently stir the gelatin to dissolve it. Once the gelatin has dissolved, place the mixture in a small container and let it cool for 30 minutes.
Cut the gelatin into squares or prism shapes, half of a square or rectangle cut diagonally. Shine a flashlight through the gelatin to see the light decay into sound spectral colors. You can also shine a laser pointer through the gelatin to see the light bend.
Create a hot tub
You can create a cool whirlpool tub using two empty 2-liter soda bottles, a metal washer with the opening smaller than the bottles mouth, and duct tape. Fill one of the 2-liter bottles 2/3 full of water.
Place the puck on the filled bottle and place the empty bottle upside down on the puck. Glue the two bottles together and quickly flip the bottles. You should see a water vortex (aka whirlpool) forming as water from the top bottle flows into the bottom bottle.
The vortex forms because the water spins faster around the edges of the bottle, creating a hole in the middle. This void then fills with air from the bottom bottle and water from the top bottle flows around it.
Build a potato battery
For this experiment you will need a potato, a galvanized nail, a piece of copper foil or a copper coin like a penny, two alligator clips with clips on both ends and a voltmeter.
Galvanized nails have a zinc coating and can be purchased at any hardware store or home improvement store. Be sure to use a fresh potato as the experiment depends on the liquid inside the potato.
Drive the galvanized nail into the potato, making sure it doesn’t go all the way through. About an inch (2.5 cm) from the nail, push in the penny.
Connect the penny to the red lead of the voltmeter using one of the alligator clips. Most voltmeters have red and black wires, but if your voltmeter has yellow and black wires, connect the penny to the yellow wire.
Connect the galvanized nail to the black wire of the voltmeter and make sure the two alligator clips are firmly attached. Your voltmeter should show a positive reading. If it shows a negative value, just reverse the leads. You produced electricity from a potato!
Build a balloon hovercraft
You can create a small hovercraft that can glide along floors and tables by bringing friction and Newton’s third law of motion into action. You will need a balloon, the cap of a 1 or 2 liter plastic soda bottle, a CD or DVD you no longer use, a carving knife or scissors and a glue gun.
First, create a nozzle by using the carving knife or scissors to create a hole in the bottle cap about the width of a drinking straw. Place glue all the way around the edge of the bottle cap and attach it to the center of the CD or DVD. Wait for the glue to dry then check if it has made a good seal with the CD or DVD, reapply glue if necessary.
Inflate the balloon and pinch the opening with your fingers then wrap the opening of the balloon around the nozzle of your hovercraft. Place the hovercraft on a flat surface and watch it go!
This “oldie but goodie” experiment shows the relationship between atmospheric pressure and temperature. You will need a few hard-boiled, peeled eggs and a glass bottle or jar with an opening a little smaller than the diameter of the hard-boiled eggs. You will also need a small piece of paper and a source of fire, such as a match or lighter. Parents should help kids with this one.
Place the glass container on a table and fold the paper into a strip that will fit inside the glass container. Light one end of the paper strip and drop the burning paper into the container. Then place the egg above the opening of the glass container and wait.
As if by magic, the egg will be slowly sucked into the bottle. This happens because the burning paper has changed the air pressure inside the bottle. Shortly after the egg is placed on top of the container, the fire will go out and the air inside the container will begin to cool and contract. This lowers the air pressure inside the container, so the pressure in the container is lower than the air pressure outside the container. Because air flows from a high pressure system to a low pressure system, the higher external pressure pushes the Egg in the bottle.
You can do all of these experiments at home with kids, and they’re a wonderful introduction to the world of science and engineering.