Fun Friday – make a periscope

We had fun making this one… a bit fiddly at parts but worth it, the boys love their new periscope! You will need…. 2 clean empty juice/milk cartons (1 Litre) Some duct tape Scissors Pen Ruler 2 small mirrors (I got a little double mirror in a make-up set in The Two Euro Shop (for €1.50) )

What you need

What to do: First, cut the tops off the two cartons and tape them one on top of the other (taping them at the open ends)

Cut tops off
Tape together

Next mark off a square on the top side of one of the cartons with your marker (I made the square 5cm X 5cm);  Cut out the square. Repeat this step on the opposite end and side of the other carton… so if the first square is on the bottom right side of your periscope cut the second square out of the top left of the periscope.

Cut a square

Now you want to fit a mirror into each end of the carton so that the reflective side of the mirror is facing you as you look in the hole and each mirror is tilted at an angle of approximately 45 degrees.  The bottom mirror is tilted up at an angle of 45 degrees and the top mirror is tilted down at an angle of 45 degrees. I was lucky, my mirrors fitted the exact width of my milk cartons so I was able to place them inside, tilt them as required and then tape them in place.  If your mirrors are wider than your carton then mark a line at the side of your carton, cut a slit and slide in your mirror.  Repeat for the other mirror then tape into place.

You should be able to look into the bottom hole and see what is reflected through the top hole….

Now all that remains is to decorate your periscope and have some fun…. you can use it to look around things or over things, great for playing spies, which is a very popular game in this house.


How does it work? The object we see is reflecting light, this light is bounced off the top mirror onto the bottom mirror which bounces the light right onto our eyes!

How it works
How it works

FEEDBACK: I love hearing from people who have tried some of these experiment so please let me know if you try this one, or even send me some photos of your finished periscope;  If you have any questions just ask!


Science blogger and writer; Owner of Dr. How's Science Wows; Mother of three junior scientists who have taught me that to be a great scientist you need to look at life through the eyes of a child!

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