Explanation of the Lemon in Water Experiment
The apparent size of the lemon in water in a glass tumbler appears to be smaller than its actual size due to the phenomenon of refraction. When light travels from one medium to another (in this case, from air to water), it changes speed and direction. This change in speed and direction causes the light rays to bend, making the lemon look closer to the surface of the water than it actually is.

Refraction of Light
- Refraction is the bending of light as it passes from one medium to another with a different optical density.
- The amount of bending depends on the difference in optical density between the two mediums.

Explanation of the Perception
- When we look at the lemon in water, our brain perceives the light rays coming from the lemon as if they are coming from a point closer to the surface of the water.
- This perceived position of the lemon is based on the direction in which the light rays are bent as they pass from water to air.

Physics Principles at Play
- The refraction of light is governed by Snell's Law, which relates the angles of incidence and refraction to the refractive indices of the two mediums.
- The refractive index of water is higher than that of air, causing the light rays to bend more when they enter the water.

Conclusion
In conclusion, the apparent size of the lemon in water in a glass tumbler appearing smaller than its actual size is a result of the phenomenon of refraction. Understanding the principles of refraction helps to explain this visual experience.