Tag Archives: illusion

Pepper’s Ghost, Part II

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this hummingbird 1_edited 1This is not the first Pepper’s Ghost illusion to appear on Pop Goes the Page. Back in 2020, we posted a kid-friendly version featuring a spirited fox. The illusion is basically a reflection trick, but it’s very effective when done right!

seeing spirits   You’ll need:

  • A clear plastic drink container lid
  • Paper (heavier paper or thin cardboard works best)
  • A small section of clear plastic (like the lid of a food container)
  • Scissors and pencil for construction
  • Cell phone

The project was originally designed and posted by artist Joshua Ellingson on his Instagram. First, wash a clear plastic drink lid. Then cut a half circle template out of paper. When you have a half circle that correctly fits at a 45 degree angle inside your cup lid, trace the paper template onto a piece of clear plastic. We used an acrylic gift box, but plastic food containers work great too. Tape the plastic half circle inside the cup lid. The hardest part is getting that 45 degree angle just right. I made about 4 templates before I finally nailed it. Here’s my finished cup with the plastic half circle:

Head to YouTube for a Pepper’s Ghost illusion on a black background. We tried a couple different ones, but had the most success with this hummingbird. Cue up the video on your phone, maximize it to full screen, and lay the phone on a tabletop. Place the cup lid on top. Finally, roll the video and turn off the lights! Your object will appear to float inside the cup lid! It’s really quite remarkable.

The original designer, Joshua Ellingson, also made a GIANT version of this craft with a thrift store bubble chair and his flat screen television. It’s a must see! And Disney’s Haunted Mansion famously employs this illusion, including an entire ballroom of ghosts!

Cotsen Ghosties

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book cover 3Last Halloween season we took a stroll through our special collections pumpkin patch. Today, we’re looking for ghosts! And we found them in this amazing optical illusion book titled Spectropia; or, Surprising Spectral Illusions. Showing ghosts everywhere, and of any color. Published by J.H. Brown in London in 1864, the book teaches the concept of “the persistency of impressions, and the production of complementary colours on, the retina.”

The illusion is very simple. In the image above, stare at the small black dot by the ghost’s neck for 20-30 seconds. Then look away at a white wall or ceiling. Her ghostly image will appear in your vision, except in different colors (in this case green wreath, blue ghost)!

Scientifically speaking, this is called an afterimage. The color receptors in your eyes work in pairs (red/green, blue/yellow, etc.). When you stare at the drawing and one color fatigues your receptors, the other receptor will step in and dominate for a bit.

The book has a very lengthy description of this concept, as well as viewing instructions that include having the “gaslight turned low.”

Spectropia also has a disclaimer at the beginning: “As an apology for the apparent disregard of taste and fine art in the plates, such figures are selected as best serve the purpose for which they are intended.”

I wish they might have reprinted the disclaimer before THIS image, which honestly is going to haunt me clear through December:

The book concludes with a grand finale image that is not a ghost, but a rainbow! Definitely try this one, because it is so cool to see the colors flip in the afterimage!

Looking more more optical spooky fun? Try making our tabletop Pepper’s Ghost illusion!

Images from Spectropia; or, Surprising Spectral Illusions. Showing ghosts everywhere, and of any color. J.H. Brown, London. Griffith and Farran.1864. Cotsen Children’s Library, Department of Special Collections, Princeton University Library.

Seeing Spirits

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seeing spiritsA quiet forest appears empty. But gaze long enough and…a fox spirit will magically appear before your eyes! No, its not Photoshop or camera trickery. It’s a simple physical stage illusion called Pepper’s Ghost (invented by English scientist John Henry Pepper in 1862). We conjured it at To Be Continued, our chapter book story time program for 6-8 year-olds. Scroll to the bottom of the post to see a video of the illusion in action!

We read Arlo Finch in the Lake of the Moon, written by John August (Roaring Brook Press, 2019). Summer camp for most kids means bonfires, canoeing, and hiking. But for Arlo Finch and his friends, it means surviving the supernatural forces of the Long Woods. Doppelgangers, menacing strangers, talking foxes, locations both in and out of time, and a mysterious object unearthed after decades in hiding test both Arlo’s courage, and his friends’ loyalty.

In the book, Arlo has a special ability to see the spectral world. And I’ve wanted to make a Pepper’s Ghost project for kids for AGES. Through an afternoon of happy experimenting, I was able to construction this inexpensive and kid-friendly tabletop version.

You’ll need:

  • 2 large tissue boxes
  • A box cutter
  • 1 toilet paper tube
  • 1 piece of glass or clear polystyrene (more on this below)
  • White card stock
  • Scissors, glue, and tape for construction
  • Markers for decorating

First, cut the lids off the top of a pair of large tissue boxes. Then cut the boxes in such a way as to create an L shape box like so:

ghost box step 1The L shape box is consists of two sections: a “forest section” and a “ghost section.”

ghost box sectionsNext, cut a small square (approximately 1.75″ x 1.75″) in the side of the box that faces the forest section. This is your viewfinder.

ghost box step 2In the book, Arlo gazes through a slipknot, a loop of rope or lacing that allows him to see and travel multidimensionally. In order to replicate that rounded view, we slid a 2.25″ piece of toilet paper tube into the viewfinder as well.

ghost box step 3 Now draw a backdrop for the wall opposite the viewfinder. I had the kids decorate a pre-cut  piece of paper or cardboard, then we glued it to the inside of the box.

ghost box step 4Next, sketch a ghost on a piece of white card stock. Here’s my tribute to Fox, a spirit from the book (and my favorite character):

fox spiritTape the ghost in the ghost section of the Pepper’s Ghost box. Though you will probably need to do a little adjusting on the exact placement, try to arrange the ghost in the center of the section. I found this gave the best results.

ghost box step 5Now for the magic! A Pepper’s Ghost illusion is essentially a reflection. For this model, the reflection is caused by a piece of glass or clear polystyrene set at a 45 degree angle in the junction of the L shaped box.

ghost box step 6During my initial test, I used a piece of glass from a 4″ x 6″ picture frame. However, I was a little uncomfortable giving multiple 6-8 year-old kids pieces of glass to take home. Luckily, I found clear polystyrene sheets on Amazon (a set of ten, 8″ x 10″ sheets cost $15). Polystyrene is plastic, lighter weight, doesn’t shatter, and you can cut it down to size with a box cutter or scissors. Testing revealed that the reflection illusion works just as well with polystyrene as glass. Yay!

The final piece of the Pepper’s Ghost illusion is the lighting. First, cover the area above the view finder with a square of cardboard…

ghost box step 7Then hinge a second square of cardboard over the ghost section. It’s important that this flap open and close. With the flap closed, the ghost will not appear through the viewfinder. But when you lift the flap, the ghost section will illuminate, causing a reflection to appear.

ghost box step 8Ready to see the illusion in action? Close the flap and peer through the viewfinder. Keep gazing through the viewfinder, then lift the flap over the ghost section. Your ghost will magically appear! I also encouraged kids to stick their hands in the forest section and try to grab the ghost. Their fingers passed right through it, of course!

This isn’t the first time the To Be Continued kids have adventured with Arlo Finch and his friends. We read the first book, Arlo Finch in the Valley of Fire earlier in the program (you can see the project we did here). The kids voted unanimously to read the sequel. It did not disappoint. The Arlo Finch books are full of action, intrigue, mystery, and humor. I highly recommend them!