Introduction: Side-Bending Goggles
The world is not as you see it. Particularly when you're sporting light-bending, orientation-ending, lenses that make even the most eagle-eyed among us go out of whack. With these side-bending goggles, the world appears a little more to the left than it really is. And it's all with just a bit of acrylic rod, frames, some hot glue, and a healthy dose of optical physics.
This is a great tool for (a) ridiculous silliness, (b) teaching optics, or (c) amplifying car-sickness by 6000%.
- What: Side-Bending Goggles
- Concepts: Vision, perception, optics, refraction, physics
- Time: ~ 45 minutes
- Cost: ~ $4
- Cheap Sunglasses Frame
- Solid Acrylic Rod (I used about 4" of 1 3/4" diameter)
- Plastic buffing set (I used Novus)
- Hot glue gun / hot glue
This was inspired by one of my favorite exhibits at the Exploratorium, and I wanted teachers everywhere to be able to create this concept at home. Let's get optical!
Step 1: Optics and Refraction
Our obsession with light is clear. We fire, we neon, we spark, we ignite, we fluoresce, we say "light up my life," we see "sparkles in the eye," and many don't leave the house in the morning before double-checking the colors of light bouncing off their clothes. The study of all of this is the study of optics.
A part of optics is the "bending of light," when suddenly as light passes from one medium to another, it propagates in a new direction. This is called refraction, and is what turns the sky blue, allows the Hubble Telescope to focus on the stars, and what makes Sherlock Holmes' monocle more than a fashion statement.
In this case, we are going to play with the shape of an acrylic rod to bend light. As you can see from just looking at it, the rod from the side can turn straight lines into curves, and even reverse what side objects appear to be coming from (see the finger example). However, if we looked straight through the end of a similar, the world would look similar to the way it does normally.
The side bending goggles come from us cutting one of the cylindrical ends of our rod at an angle. When we do this, we change which light waves make it to our eyeball. When light changes mediums (like air to plastic), rays that aren't perpendicular to the surface will be bent. Namely, from air to plastic, they will bend closer to the normal (a line drawn perpendicular to the surface of the plastic it enters). This means for our glasses as I oriented them that the light that reaches our eyes is actually light that came in from the right, and bent. This will make us perceive that all things appear further left in our field of vision than they actually are. This makes for hilarious attempts by the wearer to do everyday things. Brushing one's teeth, making tea, and opening a door now become major tasks. Interestingly, like with many things, humans can adapt.
But for now, let's make some light bend the old-fashioned way.
Step 2: Cut Your Acrylic
Set up your acrylic rod with your saw! I used an acrylic rod that was 1 3/4" in diameter because it fits pretty well with the sunglasses frames. We don't need a lot of the rod, so I set my saw to cut pretty close. I cut the rod at 30 degrees, and then flipped the rod around and cut a second matching cut.
You'll end up with two frosty lenses ready in no time!
Step 3: Sand Those Lenses
To get acrylic base to transparent takes a bit of work. I started with 220 grit sandpaper, and moved my way up (320 grit, 400, 1500, 2000) to get a finer and finer sand. Sand in circular directions on both sides of each lens, cleaning as you go!
Step 4: Buff and Polish
Time to get buff(ed)! I used a polishing set from Novus, which is cheap and lasts a really long time. First, apply plastic polish on the top and bottom of each lens, rubbing in a circular motion until dry. Tape along the side, and hold your lens with a wrench, while you buff it using a buffing brush and a drill. You can repeat and cycle through Novus 1, 2, and 3 in this case until you get it transparent (ish).
Huzzah! Clean lenses!
Step 5: Glue Those Glasses
Pop out the regular old boring frames of your classes, and replace with awesome ones! Orient the first lens to that the angled end surface is pointing to the left. Before you secure it in place, test it out with your eyes, and make sure that the back end (toward your eye) will be perpendicular to your eye. Hot glue in place.
When you add the second lens, make sure you have it lined up with the first, and test it by looking through to make sure you don't get double vision. If you do, then rotate or adjust the angle until you don't. Then glue it in place!
Step 6: Bend That Light!
With your vision bent sideways, try to do everyday things! Pour some water, open a door, point at a puppy, make origami, play dodgeball! You'll find that some things like locating your limbs are easier than others (catching or throwing things). You might also find that after a while, your brain starts to adapt, and even takes some time re-adapting when you take them off.
Play around, and experiment with changing some of the variables on your glasses.
- What happens when you change the angle of the cut?
- What about if you rotate the rods and glue them in with another orientation?
- What happens if you reverse which end is toward your eye?
- What if they point in opposite directions?
Optics is an amazing and transfixing world. Go explore, and bend it.
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