The principle of riding a swing
Kids have the know-how, but they can’t tell the principal. “How can you go so high?” Some principles are difficult to describe in words in the world, even if everyone knows. I think one of them … more
Electric Transformer
* We assume an ideal transformer where the excitation current is “0”. Electric transformer A transformer is a device for simply changing the voltage of an alternating voltage (AC). Transformers make it easy to change the … more
Integral in physics
Definite integral In the 2D coordinate plane, a definite integral is a way to find the area of a graph. In a rectangle, the only simple way to get the area is the multiplication of width … more
Kepler’s law
Kepler and Tycho Brahe There is an astronomer before talking about Kepler (Johannes Kepler 1571 ~ 1630). That’s Tycho Brahe. Tycho Brahe (1546-1601) is a famous Danish astronomer. With the development of astronomical equipment, he left … more
Torricelli’s Experiment
* You have to wear gloves when handling mercury. Torricelli’s Experiment The first person to measure the magnitude of air pressure is Italian scientist Torricelli. He was filled with mercury (Hg) in a glass tube with … more
Mandelbrot Set
This simulation supports both pinch zoom and mouse scrolling. We recommend using the Chrome browser. (to get more processing speed) Imaginary number An imaginary number consists of a number that becomes negative if you square itself. … more
What color does it look?
Three primary colors of light Red, green, and blue are called the three primary colors of light. You can create any color by adjusting the light of these three colors appropriately. red + green = yellow … more
Cell Division Model
Chromosome If you look at the onion root under a microscope, you can see cells of different shapes and sizes, such as cells with an apparent nucleus, cells that appear to be split into two cells, … more
Doppler Effect
Doppler Effect We have heard an ambulance siren and felt that the ambulance is getting closer. When the ambulance approaches, the sirens sound higher, and when they move away, the sirens sound lower. That is, when … more
Apparent Magnitude, Absolute Magnitude, and Distance to Stars
Star brightness and apparent magnitude Hipparchus of ancient Greece distinguished the stars in the night sky according to their brightness. He classified the brightest star as ‘magnitude 1’ and the darkest star as ‘magnitude 6.’ The … more
Stellar Parallax – 3D VR
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 … more