Stellar Parallax
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
Horizontal Coordinate System
Celestial coordinate system A celestial sphere is an abstract sphere centered on an observer. All objects in the sky can be conceived as projected upon the celestial sphere’s inner surface. Horizontal Coordinate System The horizontal Coordinate System is a celestial … more
Equatorial Coordinate System
Celestial coordinate system A celestial sphere is an abstract sphere centered on an observer. All objects in the sky can be conceived as projected upon the celestial sphere’s inner surface. Equatorial system The equatorial coordinate system is the most basic … more
Constellations
Constellations If you look at the sky where there is no light on a clear night, there are so many stars that can not count. Thousands of years ago, the ancients linked stars to create constellations named after animals, objects, … more
Chemical Change of Candle
Paraffin, the main ingredient of candles Paraffin, the main ingredient of candles, is alkane hydrocarbons in which 20 to 40 carbon atoms are linked in a chain. It does not dissolve in water as a polar solvent but dissolves well … more
Celestial Equator and the Ecliptic
The tilt relationship of the celestial sphere and ecliptic The celestial equator is the enlargement of the earth’s equator to the celestial sphere. Therefore, the celestial equator can be represented by a line fixed on the celestial sphere. The ecliptic … more
Theo Jansen Mechanism
Theo Jansen He is the leading artist of kinetic art with the nickname of Da Vinci in the 21st century. He is famous for making wind-driven structures using simple materials such as PET bottles, tubes, and cable ties. Since 1990, … more
Charles’s Law
Charle’s Law Assuming constant pressure, increasing the temperature of the gas will speed up the molecular motion. As the gas often collides with the vessel wall, the volume increases. Conversely, if you lower the temperature of the gas, the molecular … more
Boyle’s Law
Boyle’s Law If you press the piston of a syringe containing a certain number of gas molecules, the gas molecules’ space is reduced. Therefore, the gas molecules collide with the syringe wall more and more. As a result, the pressure … more
Apparent Motion of Mars
Apparent Motion of Mars If you observe the motion of Mars, you can see that you go forward and go backward. This procession of Mars has been regarded as mysterious since ancient times. In the past, the human did not … more
Addition of Force
Three elements of force When a force acts on an object, the object’s motion varies depending on the Three elements of force. That is the magnitude, direction, and point of action. Therefore, when displaying a force, you must indicate the … more
Water Waves
Water Wave When you throw a stone into a calm lake, a circle of concentric waves is created and spreads around. The phenomenon that vibration created in one place spreads to the surroundings is called a wave. If you make … more