I've been doing this activity with learners of all ages for a few years now, and it's always a blast! This activity started as a blog post that I wrote in 2019 for a local science center, and was made possible by folks who have generously and freely shared their resources for creating optical illusions. (One great example that talks about the history and science of this illusion can be found here: https://www.ontariosciencecentre.ca/media/1670/hauntedhologram.pdf).
To honor that generosity, I'm sharing back some of the resources and instructions I've used to help learners create their own pepper's ghost illusions.
With Halloween coming up soon, now is the perfect time to try creating your own spooky illusion like the one above. All you need is a sheet of clear plastic and a smartphone or tablet.
Instructions
1. Gather these materials:
If you're using a transparency sheet that you can't print directly onto, print the pyramid hologram template onto a sheet of paper, and trace the outline onto your transparency. If you're using printer-compatible transparency sheets you can print the template right onto your sheets!
This template has two sizes you can choose from, tablet-sized and mobile phone-sized:
2. Cut, fold, and tape the template according to the template instructions.
3. Test your illusion. You can find a list of videos that work well for this illusion here or by searching “3D hologram videos” on YouTube. Find a video that you like and place the plastic pyramid on your smartphone or tablet screen.
Tips for making your illusion look great:
Turn the screen brightness on your smartphone or tablet all the way up
Dim the lights in your room or turn the lights off
Set up your smartphone or tablet screen so that you can see the pyramid at eye level
Cut your plastic pyramid carefully and don’t be afraid to take apart your pyramid and tape it back together.
Looking for a fun extension?
Code your own Pepper’s Ghost illusion animation using Scratch. Here’s an example of an animation that I created in Scratch:
You can get started with making your own animation by remixing my Scratch project. To remix this project you can click on this link and press the green button that says “remix”. You need to be logged in to Scratch to see the remix button. If you just want to tinker with the program, you can press the "see inside" button.
Here are some challenges to get you started:
Make the dinosaur move slower or faster (hint: change the number next to where the code says “wait”)
Replace the dinosaur with another character
Find another way to control how the dinosaur moves, can you create a noise-activated dinosaur hologram? Or how about a micro:bit - controlled hologram?
Coming soon: Use the OctoStudio app to program your own interactive animation on a table or smartphone.