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Put on your best spy disguise: it’s time to become a spy with today’s DIY periscope experiment!
This experiment involves kids building their own periscope using a milk carton and mirrors to learn all about reflection, how periscopes work, and some engineering principles.
Go find some hiding corners that you can peek out from with your periscope and let’s make it fun!
How to make the Make a Periscope experiment
Supplies you will need
For this experiment, you’ll need:
- Milk carton (2)
- Scissors or knife
- Mirrors (2)
- Duct tape
- Optional: decorations like markers, stickers, glitter, etc.
Before you start
Please watch everyone’s fingers around the scissors and/or knife.
Instructions
Here is how to do this experiment with your child:
Step 1: Cut out 45-degree slits on each side of each milk carton
I decided to use a marker to mark the areas that I wanted to cut (see picture below).
Using a knife, scissors, or a box cutter, cut small slits at a 45-degree angle on each side of the two milk cartons.
Step 2: Cut out a viewfinder in each milk carton
Next, you will need to cut out a square hole at the bottom of each milk carton.
Step 3: Cut cardboard backing for each mirror
If your mirrors are smaller than the width of your milk cartons, you will have to make a cardboard backing for your mirrors.
I decided to use a ruler to measure out the length and width of the size I needed. The cardboard backing should be about 1/2″ wider than the milk carton and almost as long as the slit you made in the previous step.
Step 4: Add the mirrors to the milk cartons
If you have to use a cardboard backing for your mirrors, be sure to hot glue the mirrors to the backing first.
Place the mirrors into the slits of the milk cartons with the mirror facing out toward the square opening you cut.
Step 5: Tape the milk cartons together
Last step! Line the two milk cartons up so the square openings you cut earlier face opposite directions.
Use duct tape to adhere the two milk cartons together. Your periscope is ready to go!
Step 6: Use your periscope!
This is a great opportunity to talk about reflection (see below for talking points).
You can take the mirrors out and even play around with them to talk through reflection, then add them back in the periscope to see that in action.
The STEM behind the Make a Periscope experiment
This experiment teaches:
- History of the periscope
- Reflection
- Engineering principles
How it works
Our experiment involves making a periscope out of everyday items like a milk carton and mirrors.
Periscopes use mirrors to bend light. The light enters the tube, hits a 45-degree mirror at the top, bounces down the tube, hits another 45-degree mirror at the bottom, and travels to your eye. This allows you to see what’s ahead despite being hidden!
It teaches kids about reflection, how periscopes work, and some engineering principles.
The history of the periscope
Periscopes have roots in not only the scientific world but in military applications too!
In 1854, French scientist Hippolyte Marié-Davy invented the first naval periscope, which was a vertical tube with two small mirrors fixed at each end. Seeing above the water while staying hidden underwater is crucial for submarines, and periscopes help solve that problem.
Simple periscopes use mirrors, but more complex versions used in submarines or tanks might have prisms or lenses to magnify the image and make it easier to see. Thomas H. Doughty of the US Navy invented this new version using prisms for use in the Civil War.
Reflection
Building a periscope is a great hands-on way for kids to grasp reflection.
The key to the periscope’s magic is how light bounces off the mirrors. Kids can see this firsthand. By looking through the peephole, they see an image even though they aren’t looking directly at the object. This is because the light travels from the object, hits the top mirror, and then bounces at an angle (reflects) to the second mirror. The second mirror reflects the light again, sending it to their eye.
If you want to demonstrate this more concretely, try playing with the mirrors before you place them in the periscope. You can toy with the mirrors’ angles to show reflection to your child.
Engineering principles
Experimenting with the mirrors’ angles shows the importance of precision in fields like engineering. If the angles are slightly off, it will distort your image or might not even display that image.
Building the periscope involves following instructions, measuring, and putting things together. This helps develop problem-solving and critical thinking skills.
More experiments about reflection and refraction to try out with your child
- Kaleidoscope Creations: Unleashing Colors and Light at Home!
- Water’s Trick: Why the Arrow Changes Direction
- Making Rainbows: A simple prism experiment
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