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
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Standing Waves in various situations
A standing wave occurs when incoming and reflected waves interfere with each other. It produces a wave pattern that appears to be stationary. Nodes are locations where particles of the medium appear to be at rest. And, antinodes are locations … more
Pulleys with Many Wire
Movable Pulley Movable pulleys can move axes, unlike fixed pulleys. Movable pulleys have the advantage of being able to move with less force. But, the distance that I have to move is longer than the fixed pulley. So, there is … more
Pulleys with One Wire
Movable Pulley Movable pulleys can move axes, unlike fixed pulleys. Movable pulleys have the advantage of being able to move with less force. But, the distance that I have to move is longer than the fixed pulley. So, there is … 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
Rainbow Colors
Color and Eye Recognition Visible light has various colors. Light has a different color depending on the wavelength (or frequency). So, how do people perceive color? Cone cells in the eye’s retina recognize color. There are three kinds of cone … more
Principle of Mirror
Why is the incident angle and the reflection angle the same? ‘Law of reflection’ has the word ‘law’ attached. ‘Law’ refers to a situation in which a natural phenomenon happens repeatedly and without exceptions. In other words, ‘law’ only tells … more
Is Sun Rays Parallel?
Parallel sunlight The radiant energy of the sun spreads in every direction. However, since the sun and the earth are far apart, we assume that they are usually almost parallel. Ancient Greece’s Eratosthenes measured Earth’s size quite accurately, assuming that … more
Parallax of Eyes
Parallax When an object is close to me, you can use a ruler to measure the distance. But, it isn’t easy to measure when the object is away from me. In this case, how can you measure the distance? Humans … more
Law of Reflection
The law of reflection Consider a light-ray incident on a plane mirror, the angle of reflection is equal to the incidence angle. This is the law of reflection. When looking at the end of the head and feet with a … more
Maximum Elongation of Inner Planets
Maximum Elongation of Inner Planets From the Earth’s perspective, the inner planets seem to stay near the sun. This is because it orbits the inside of the earth. So We cannot see the inner planets in the middle of the … more
Fourier Analysis
Fourier series A Fourier series is a way to represent a function as the sum of simple sine waves. A simple trigonometric function consists of a smooth surface. If you continue to add these trigonometric functions, you can get a … more