Kinetic Energy and Temperature
You may recall that every solid, liquid, and gas is made of particles. How does the motion
of the particles relate to the energy a substance has? 

Kinetic Energy
What do a soaring soccer ball and the particles that make up hot maple syrup have in
common? They both have energy, or the ability to cause change. What type of energy
does a moving soccer ball have? Kinetic energy! Recall that kinetic energy is energy due
to motion. When someone kicks a ball and puts it in motion, the ball has kinetic energy.

You may recall kinetic energy comes in a variety of different forms, including, thermal energy, electrical energy, radiant energy, and sound energy. Usually, you can find more than one form of kinetic energy being used, like with a toaster. 

Temperature
When you think of temperature, you probably think of it as a measurement of how warm or cold something is. However, scientists define temperature in terms of kinetic energy. 

Temperature and Kinetic Energy
The particles that make up the air inside and outside a house are moving. However, they are not moving at the same speed. On a cold winter evening, the particles in the air in the warm house move faster and have more kinetic energy than the air particles outside. Temperature is the measure of the average kinetic energy of the particles in a material,

You might have seen the temperature in a weather report given in degrees Fahrenheit and degrees Celsius. On the Fahrenheit scale, water freezes at 32° and boils at 212", On the Celsius scale, water freezes at 0° and boils, at100°. The Celsius scale is used by scientists worldwide. To convert from Celsius to Fahrenheit, use the 

Equation:

The greater the average kinetic energy of particles, the greater the temperature. The temperature of the air inside the house is higher than the temperature of the air outside the house. This is because the particles that make up the air inside the house have greater average kinetic energy than those outside. In other words, the particles of air inside the house are moving at a greater average speed than those outside. Does the relationship between kinetic energy and temperature hold true for liquids as well? Let's find out!

Particles
When the dye is first put into the beakers, the dye particles are close together. Water particles, like the particles in allliquids, constantly bump and flow past each other randomly. The movement and collisions of the water particles push the dye particles around, causing the coloring to spread out, or diffuse. Particles diffuse until the dye particles are evenly mixed with the water particles.

Now consider the dye particles after some time in the two beakers. The beaker with a higher temperature has particles that are moving more quickly and bumping into the dye particles more often. The faster the particles are moving, the faster the dye diffuses due to the greater kinetic energy of the particles.

Temperature and kinetic energy are directly related i terms of particle movement, which is why the dye spreads faster in the warmer beaker.

Thermal Equilibrium
Recall the flying soccer ball and the hot maple syrup. The particles that make up the soccer ball and the maple syrup, or any material, not only have kinetic energy, they also have thermal energy.

Thermal Energy
Thermal energy,is the energy due to the motion of particles that make up an object. This is referring to the energy contained in a system that affects temperature. Recall that the temperature of a substance is related to the average kinetic energy of the particles that make up that substance. What other factors are related to the energy of a substance?

Number of Particles
Which contains more energy—a glass of water at 20°C or a bathtub full of water at 20°C? A bathtub full of water contains more energy than a glass of water at the same temperature. The bathtub contains more particles of water than the glass.

State of Matter
As aliquid, the water in the pot contains more thermal energy than a solid would at the same temperature. In the image, the particles of the solid pasta have less energy than the water. Water vapor above the pot has more energy than the water in the pot because it is a gas. The state of matter affects how much total energy there is in the system

Type of Matter
Did you notice that the pasta and the water are different substances? This plays a ole in the amount of thermal energy a substance contains. Substances also contain different amounts of thermal energy because they are made up of different types of particles. Thermal energy depends on the type of matter that makes up a substance.

Heat
Have you ever held a cup of hot cocoa on a cold day? When you do, thermal energy moves from the warm cup to your hands. The movement of thermal energy from a warmer object to a cooler object is called heat. Heat also refers to thermal energy moving in a predictable pattern from warmer to cooler.

Just as temperature and thermal energy are not the same thing, neither are heat and thermal energy. All objects have thermal energy. However, you heat something when thermal energy transfers from one object to another. Holding a cup of hot cocoa heats your hands because thermal energy transfers from the hot cocoa to your hands.

Thermal Equilibrium

The rate at which heating occurs depends on the difference in temperatures between objects. The difference in temperatures between the hot cocoa and the air is greater than the difference in temperatures between the hot cocoa and the cup. The hot cocoa heats the air more than it heats the cup. Heating continues until all objects in contact are the same temperature. This is called thermal equilibrium. Thermal equilibrium is when the temperature of materials that are in contact are the same.

Now, think about the cup of hot cocoa again. The thermal energy moves from areas of warm to cold. This means the hot cocoa transfers thermal energy to the air, which lowers the temperature in the hot cocoa. The air warms up in return until all substances within the system reach thermal equilibrium. During this time particles transfer kinetic energy back and forth, colliding with each other.