Monthly Archives: July 2017

DIY: 3D Hologram

Have you ever wanted to feel like you exist in a Sci-Fi world? Or make something that just seems impossible? With this DIY 3D Hologram you can! It is a simple at-home craft that will dazzle your friends and family.

3D Hologram

All you will need:

  • Printable template
  • Transparency sheet
  • Scissors  
  • Marker
  • Ruler
  • Smartphone or tablet

3D Hologram 1

Step 1: Trace the template using your marker and ruler.

Step 2: Make the cuts to your transparency sheet.

Step 3: Fold the edges to form a pyramid.

Step 4: Find an awesome 3D video online for your smartphone or tablet to project.

Step 5: Place the pyramid in the center of your device, get down to the same level as the device, watch, and enjoy!

It’s as simple as that to transform your ordinary device into an out-of-this-world experience. But how does it work?

3D Hologram bird

Optics is all about the manipulation of light with lenses, mirrors, and splitters. Light can bend, get absorbed, and reflect. When watching the video on your device, the light being emitted from the screen is mostly aimed straight up. Once the pyramid is added, the plastic that hangs over the images acts as a splitter. It allows light to both travel through it and get reflected at the same angle at which it enters. The four different sides will add the four images into the center, creating what looks like a 3D hologram!

3D Hologram world

We had way too much fun creating this 3D hologram projectors. Be sure to give this a try and let us know what you think!

Written by: Mimi Garai



With the glow wall and glow-in-the-dark water bottles and frisbees here at AstroCamp, we often get asked how exactly they work. Well, it all comes down to a phenomenon called phosphorescence.


Like fluorescence, which is what you get when you shine a blacklight on something or pass electricity through a container of gas, phosphorescence involves the atoms of a substance absorbing energy and then retransmitting it as light. Unlike fluorescence, however, phosphorescent materials continue releasing light after the energy source is removed like Chloe’s shadow remaining after we use our flashbulb above. If not, your glow-in-the-dark water bottle wouldn’t work after the sun sets, which would be pretty useless. To understand how they keep releasing energy, we need to go down to the quantum level.

Phosphorescence is the result of energy transitions called “forbidden transitions” in quantum mechanics. These transitions are not universally impossible, but are actually just incapable of happening at a specific level. Once the level changes, however, these transitions are entirely possible; resulting in the energy transitions being slow and lasting after the energy source has been removed. Phosphorescence’s transitions involve a spin flip inside the atoms of the material, which is impossible in an electric dipole, but possible in a quadrupole.

phosphorescence 1

Phosphorescence will function with any wavelength of light, but higher energy light like UV will produce a stronger and longer lasting glow. That can be seen clearly with the different lights above. We used red and violet flashlights and a violet laser, and you can see clearly that the red flashlight has the dimmest glow and the laser has the brightest. As light goes up in wavelength and down in frequency, like going from violet light to red light, it carries less energy. The laser and one flashlight are both violet though, so how is one releasing more energy? Lasers are amplified and focused light of one specific wavelength, but a flashlight is many wavelengths spreading out in a cone, giving it inherently less energy than a laser of the same color.

phosphorescence 2

Now that you know how fluorescence works, try using different kinds of light on any glow-in-the-dark things you have and see what happens; have fun!

The Physics Behind Curveballs

With the MLB All-Star Game happening, you might be wondering how curveballs and other pitches actually work. Well wonder no longer because Derrick has the answer for you! It all has to do with the 216 raised red stitches altering the airflow around the ball.

curveballs 1


If the ball leaves the pitcher’s hands spinning counterclockwise like above, the stitches are causing air to move faster above the ball than it does below. If you remember our post about Bernoulli’s Principle, you’ll know that this creates a lower pressure zone above the ball. That lower pressure causes a form of lift referred to as the Magnus Effect, keeping the ball from dropping as much on its way to the plate, delivering a fastball to the batter.


If the pitcher instead twists their wrist in another direction, the Magnus Effect pulls the ball in the direction of lower pressure. Pitchers can use this to make balls drop to the ground quicker or veer off to the side, giving curveballs their namesake.

How Does Sunscreen Work?

Summer camp is underway here at AstroCamp and one of the things campers get told time and time again is to wear sunscreen. We all know that sunscreen helps prevent sunburns and skin cancer, but how?


Well, sunscreen is composed of a mix of organic and inorganic compounds that work together to limit our exposure to the ultraviolet light streaming at us from the sun. The inorganic compounds, including zinc oxide and titanium dioxide, act like a bunch of microscopic mirrors, reflecting or scattering the UV light before it can reach our skin. The organic molecules absorb the UV light instead of letting our skin absorb it. Absorbing this radiation slowly breaks down the organic molecules, which is why you need to reapply sunscreen after a while.

sunscreen 2

To visualize that, we put a piece of black construction paper out in the sun for a few hours. Half of the paper was covered in sunscreen and half was left blank, with the bottle crossing the border between both halves. You can clearly see that the area covered in sunscreen held its dark color much better than the side left unprotected. In fact, the area coated in sunscreen is almost as dark as the section under the bottle, which took no UV damage.

For those of you who remember our piece on bleach, you’ll know that the pigments we see come from chemicals called chromophores. Unlike in that video, however, the source of breaking up the chromophores in the paper is UV radiation. It was absorbed into the paper and broke apart the bonds in the chromophores, causing the paper to fade; this is much like how it damages our cells, causing them to potentially create defective cells which may eventually lead to skin cancer.

So remember, if you’re going into harsh sunlight, make sure you have sunscreen on.


We would like to thank you for visiting our blog. AstroCamp is a hands-on physical science program with an emphasis on astronomy and space exploration. Our classes and activities are designed to inspire students toward future success in their academic and personal pursuits. This blog is intended to provide you with up-to-date news and information about our camp programs, as well as current science and astronomical happenings. This blog has been created by our staff who have at least a Bachelors Degree in Physics or Astronomy, however it is not uncommon for them to have a Masters Degree or PhD. We encourage you to also follow us on Facebook, Instagram, Google+, Twitter, and Vine to see even more of our interesting science, space and astronomy information. Feel free to leave comments, questions, or share our blog with others. Please visit for additional information. Happy Reading!