# Energy

Picture courtesy of Atoma Figure courtesy of RJ Hall To help this physics teacher "get it," a physics phenomenon known as the index of refraction must be explained. You may have heard the word refraction before. It sounds a lot like reflection and has to do with light; however, it is very different. If you've never tried that, you can experiment in a much less scary way. When light travels from one density to another it bends. Physicists have tested the index of refraction for many materials. Now, don't forget about the Pyrex beaker that the person in the video uses to hold the water.

The same thing happens with a dry penny under an empty beaker. When the light travels from the air, through the beaker, into the water, back through the base of the beaker, and through the air to the penny (Figure 2), the index of refraction is too great for the viewer to be able to see the penny. Guitar Strings and Longitudinal Waves. A sound wave is produced by a vibrating object.

As a guitar string vibrates, it sets surrounding air molecules into vibrational motion. The frequency at which these air molecules vibrate is equal to the frequency of vibration of the guitar string. The back and forth vibrations of the surrounding air molecules creates a pressure wave which travels outward from its source. This pressure wave consists of compressions and rarefactions. The compressions are regions of high pressure, where the air molecules are compressed into a small region of space. In solids, sound can exist as either a longitudinal or a transverse wave. A guitar string vibrating by itself does not produce a very loud sound. For more information on physical descriptions of waves, visit The Physics Classroom Tutorial. Black, white or silver? - Years 7-8. How Does Heat Travel? Heat can be transferred from one place to another by three methods: conduction in solids, convection of fluids (liquids or gases), and radiation through anything that will allow radiation to pass.

The method used to transfer heat is usually the one that is the most efficient. If there is a temperature difference in a system, heat will always move from higher to lower temperatures. Heat & Temperature HOME PAGE| What is Heat? | What is Temperature? | Heat vs Temperature| Heat Transfer| Detecting Heat| Measuring Temperature| What Do We Learn From Heat?

Kelvin Temperature Scale: Facts and History. The Kelvin temperature scale was the brainchild of Belfast-born British inventor and scientist William Thomson — also known as Lord Kelvin.

It is one of the three best-known scales used to measure temperature, along with Fahrenheit and Celsius. Like other temperature scales, the freezing and boiling points of water are factors in establishing the scale’s range. There are 100 degrees between the temperate at which water freezes at (273.16 K) and boils (373.16 K).

Each unit on this scale, called a Kelvin rather than a degree, is equal to a degree on the Celsius scale. For this reason, just the K, not the degree symbol, is used when reporting temperatures in Kelvin. ConservationofEnergyCloze. Forms of Energy: Motion, Heat, Light, Sound. What forms of energy is Raul using to move his LEGO car?

When he was a teenager in Romania, Raul Oaida became obsessed with building things: a jet-engine bike, a tiny spaceship, a LEGO car that runs on air. Why? Well, why not? You can see more cool stories about energy at The Adaptors website. Like video and audio? Energy comes in two basic forms: potential and kinetic Potential Energy is any type of stored energy. Kinetic Energy is found in movement.

Energy can shift between forms, but it is never destroyed or created. A car transforms the potential energy trapped in gasoline into various types of energy that help the wheels turn and get the car to move. Power plants transform one form of energy into a very useful form, electricity. These transformations are hardly perfect. Forms of Potential Energy Systems can increase gravitational energy as mass moves away from the center of Earth or other objects that are large enough to generate significant gravity (our sun, the planets and stars).