Why does a glass of water flip an image? Pretty interesting, right? Not only have we prepared a cool free printables, that you can download, but also we are going to deliver a simple explanation for this cool science optical trick.
Why do images flip in glass?
When you look at a figure on a piece of paper through a glass filled with water, the image appears to be flipped or reversed. This phenomenon occurs due to the principles of light refraction and the way lenses work.
Refraction of Light
When light travels from one medium to another (like from air to water), it bends or refracts due to the change in the speed of light in these media. Water has a higher refractive index than air, causing light rays to bend towards the normal line (an imaginary line perpendicular to the interface between the two media).
Lens Effect
The curved surface of the water in the glass acts like a lens. Specifically, the shape of the water surface acts as a convex lens when viewed from the air side. Convex lenses converge light rays, which means they can focus light to a point.
Upright to Inverted
For objects very close to the lens, like the figure on your paper, the image formed can be magnified and inverted. This inversion happens because light rays from the top of the object (figure) are refracted through the water in such a way that they cross over before reaching your eyes, making what was at the top appear at the bottom and vice versa.
Image Formation
When you look through the water, the light from the figure passes through this convex lens formed by the water’s surface, and due to the bending of light, the image you see is flipped.
Here’s a breakdown:
- Real vs. Virtual Images: For objects closer than the focal point of this makeshift lens (which depends on the curvature of the water surface), a virtual, upright image would be formed if the water’s curvature wasn’t significant. However, because the water’s surface curvature acts more like a strong lens for objects very close to it, it inverts the image.
- Distance and Magnification: The exact behavior (whether the image is inverted or not) also depends on how close the paper is to the glass of water. The closer the paper, the more likely you are to see an inverted image due to the strong lens effect.
Free Printable Image Flip Water Glass
This optical trick is similar to what happens with magnifying glasses or when observing objects through lenses in microscopes or telescopes, where the position of the object relative to the lens’s focal points determines the characteristics of the image formed. However, in your case, the informal setup with water in a glass leads to an interesting demonstration of these principles in everyday life.
If you would like to try out some Christmas image flipping, Toddler in Action has the right free printable for you.
Happy Experimenting!