Hologram in Your Hand
It really looks like a hologram… but this lesson demonstrates the Law of Reflection by creating a Pepper’s Ghost with a PepperGram Projector™ and distinguishes the difference between a virtual image and a hologram.
Grades: 1 to 14
Duration: 1/2 Hour – 1 Hour
Supplies: smartphone, Peppergram Projector™
NGSS Connections PS4.B: Electromagnetic Radiation
- Objects can bee seen if light is available to illuminate them or if they give off their own light (1-PS4-2)
- Some materials allow light to pass through them, others allow only some light through and others block all the light and create a dark shadow on any surface beyond them, where the light can not reach. Mirrors can be used to redirect a light beam (1-PS4-3)
- An object can bee seen when light reflected from its surface enters the eyes (4-PS4-2)
- When light shines on an object, it is reflected, absorbed, or transmitted through the object, depending on the object’s material and the frequency (color) of the light (MS-PS4-2)
- The path that light travels can be traced as straight lines, except as surfaced between different transparent materials (e.g. air and water, air and glass) where the light path bends (MS-PS4-2)
Let’s create a Pepper’s Ghost with the Peppergram Projector™. Try to make the room as dark as possible. This will make for clearer images.
Remove the protective film from each side of the PepperGram™.
Fold along the three lines on the PepperGram™ – you might have to press quite hard to get the plastic to snap into place. Your PepperGram™ should now look like an upside-down pyramid.
Wipe down the PepperGram Projector™ with a clean cloth. You’ll want it free of fingerprints and dust for the best result.
Search YouTube for any “4 Faces Hologram Videos”. For a jellyfish, try the one included in this step.
Make sure your smartphone screen is set at its brightest.
Place the PepperGram™ in the middle of the screen. You can use one of the mounting squares to stick it down so that it doesn’t move. Crouch down so that the PepperGram™ is at eye-level and play the video!
Move the Peppergram™ slightly slower than eye-level. What do you see now? Using your knowledge of the law of reflection, why do you think it’s important that you look directly into the side of the Peppergram™?
We’re now going to confirm that the PepperGram™ does not create holograms!
Pause the video. Take a good look at the jellyfish, then move around the Peppergram™ and compare. What do you notice? Does the jellyfish “turn around”?
Now switch off the screen of the smartphone. Is the jellyfish still swimming? What does this tell us about the image?