# Reverse Arrows with Water Optical Illusion

How’s everyone out there doing today? It’s the beginning of the weekend and I couldn’t be happier. I’m certainly going to go out and enjoy some fun in the sun, but I want to hook you all up with a new optical illusion before I do that. I certainly hope you all enjoy it and maybe it makes you think a little bit.

A viewer of MoIllusions decided to submit this brain teaser optical illusion to us and  I decided that it was definitely worthy of being posted up on the site. So, first off, I’d like to give thanks to that user for his submission and I’d also like to invite the rest of you to submit optical illusions anytime you like.

Anyways, today’s optical illusion is pretty cool and is known as the reverse arrows with water optical illusion. I have a feeling you’re really going to like this one, so scroll down to check it out.

So, I have to ask, how was this person able to pull off such an illusion? If you know, you should leave a comment and tell me how they did it. It’s a very basic optical illusion you can do at home, so I want to see how many people can get this right.

Want to check out another amazing optical illusion? Have a look at this Sunset Marilyn optical illusion.

## 9 Replies to “Reverse Arrows with Water Optical Illusion”

1. fab says:

it’s easy. is glued paper on the glass, and the person turns the glass

2. Marie Mayer says:

Just basic refraction of water

3. snowgods says:

it’s all about the optics, the glass is acting as a lense, ands adding the water changes the refractive index and the focal point. note the exact position of the glass is important

4. JohnE says:

Light refraction different through air vs. water. Need cylindrical glass at a right distance to make the two arrows be the same size.

1. James Dean says:

Very good :)

5. Nick says:

It’s not an illusion IMO. It is basic optical physics. Now if they could have kept one arrow pointing each direction with a full glass, that would have been cool.

6. they water glass is an easy one. they put a round mirror in the glass

7. sony says:

When the arrow is moved to a particular distance behind the glass, it looks like it reversed itself. When light passes from one material to another, it can bend or refract. In the experiment that you just completed, light traveled from the air, through the glass, through the water, through the back of the glass, and then back through the air, before hitting the arrow. Anytime that light passes from one medium, or material, into another, it refracts.

Just because light bends when it travels through different materials, doesn’t explain why the arrow reverses itself. To explain this, you must think about the glass of water as if it is a magnifying glass. When light goes through a magnifying glass the light bends toward the center. Where the light all comes together is called the focal point, but beyond the focal point the image appears to reverse because the light rays that were bent pass each other and the light that was on the right side is now on the left and the left on the right, which makes the arrow appear to be reversed.

1. James Dean says:

Great job explaining this one. :)