Physics

Glass transmits visible light but blocks infrared thermal radiation from escaping. This amplifies the heat trapping effect. A solar cooker, or solar oven, is_x000D_ a device which uses the energy of direct sunlight to heat food or drink to cook it or sterilize it. The vast majority of the solar cookers presently in use are relatively cheap, low-tech devices. Because they use no fuel and cost nothing to operate, many nonprofit organizations are promoting their use worldwide to help reduce fuel costs for low-income people, reduce air pollution and slow deforestation and desertification, caused by use of firewood for cooking. Solar cooking is a form of outdoor cooking and is often used in situations where minimal fuel consumption is important, or the danger of accidental fires is high.

Einstein presented his general theory of relativity more than 100 years ago. According to that foundational theory, now known as special relativity, the laws of physics don’t care how fast you are going — the laws of physics and the speed of light are the same.

Optics and thermodynamics are part of the classical physics.

It is a universal attractive force. It is directly proportional to the product of the masses of the two bodies. It obeys inverse square law. It is a long range force and does not need any intervening medium for its operation.

The velocity of sound in dry air is approximately 343 m/s at a temperature of 25 °C. Therefore, the reflecting object must be more than 17.2 m from the sound source for echo to be perceived by a person located at the source.

Dynamo is a device that converts mechanical energy into electrical energy. Its other name is electric generator. A device which has a reversed effect to this is the electric motor. An electric motor is a device which converts electric energy to mechanical energy.

Johannes Kepler published his first two laws about planetary motion in 1609 , having found them by analyzing the astronomical observations of Tycho Brahe. Kepler’s third law was published in 1619.

As light passes from air into glass, there is reduction of velocity. Due to longer wavelengths, red waves travel fastest and is refracted the least, while violet waves travel the slowest and is refracted the most.

The separation of oil and water is caused due to the difference in surface tension of the two liquids. The water molecules stick together tightly and does not mix with the oil because water molecules are attracted to each other very strongly, forming an invisible “skin” of surface tension around each drop.

Adding salt to the water increases the density of the solution because the salt increases the mass without changing the volume very much. When enough salt is added to the water, the saltwater solution’s density becomes higher than the egg’s, so the egg will then float.