## Light Refraction

You can drag the path of light. Refraction is the bending of a wave caused by a change in its speed as it moves from one medium to another. This occurs because of the slow speed of light in dense … more

## Heart Rate Counter

Pulse Blood vessels are elastic. When the heart contracts, the blood vessels dilate; when the heart relaxes, the vessels constrict. Hemoglobin in the blood absorbs particular light. Therefore, when light is applied to human tissue, the passage of light varies … more

## Relativity of Simultaneity

Let’s assume there is a light source in the middle of the train and sensors on both sides to detect the light. From the point of view of an observer inside the train, the two light sensors are the same … more

## Minkowski Spacetime

Minkowski Spacetime Minkowski spacetime (or Minkowski space) is a coordinate system devised by German mathematician Minkowski. The peculiar thing is that the coordinate system contains space and time. Minkowski spacetime uses matrices to express a four-dimensional coordinate system (x, y, … more

## Rainbow by Raindrops

A rainbow is a natural phenomenon where the dispersion of light is most visible. As you know, We can see a rainbow after rain because the water droplets bend and disperse the light. For example, if we spray water on … more

## Prism

The refractive index of the prism glass was assumed to be 1.51 for red light (≒700 nm) and 1.53 for blue light (≒400 nm). The speed of light is about 300,000km/s. Light travels fastest in a vacuum. As light passes … more

## Diffraction Grating

The diffraction grating is a transparent plate with very narrow lines on the surface. Light (photons) like to go in the same phase. In the same phase, constructive interference occurs. If the phases are different, the waves cancel each other … more

## Electromagnetic Waves around of Visible Rays

Electromagnetic radiation refers to the electromagnetic field waves radiating through space-time, carrying electromagnetic radiant energy. It includes radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays. Types of Electromagnetic Wave Electromagnetic waves are classified based on the length … more

## Thin Film Interference

Interference patterns seen in thin films If a thin oil film is floating on the water, you will see a beautiful pattern appear on the oil film. This is because the two waves interfere with each other. One wave is … more

## See the Light

Even if the object does not shine by itself, why can we see it? The eye is the organ that feels light. Even if the object does not shine by itself, why can we see it? Most objects can reflect … more

## Why is the Sky Blue?

What is the size of the light? There is no exact concept of sizing the light, but it uses the wavelength of the light. Wavelength is the distance traveled by a wave before it vibrates once and returns to its … more

## Rainbow Formation

A rainbow is a natural phenomenon where the dispersion of light is most visible. As you know, We can see a rainbow after it rains because the water droplets bend and disperse the light. For example, if we spray water … more