Chapter 6 Section 1

Temperature Remember that temperature is the measure of average kinetic energy of an object. How do you think temperature and heat are related? Remember that all matter is made up of particles , and that these particles are in constant random motion. The more motion there is the more kinetic energy there is, the more energy the higher the temperature reads.

So as the temperature increases the average speed of the particles increase.

Thermal Energy Thermal energy is not the same as temperature. It is defined as the total of kinetic and potential energy of the PARTICLES. Not to be confused with mechanical energy which was the total of kinetic and potential energy in the SYSTEM.

Thermal energy and temperature are related though. When the temperature of an object increases it’s kinetic energy increases. When this happens, the thermal energy increases as well since it is dependent on kinetic energy. So thermal energy increases when temperature increases. Which do you thing has more thermal energy steam at 100 °C or water at 100 °C ?

Thermal Energy and Mass The more mass there is the more thermal energy there is. Even if you compare two things that are the same temperature. Both of these glasses contain water that is 20°C, but the smaller glass has 20 ml of water and the larger glass has 40 ml. So the larger glass has more thermal energy

Heat Heat is thermal energy that transfers from an object with a higher temperature to an object with a lower temperature. It is a form of energy so it is measured in joules. It always flows from warmer to cooler material.

Specific Heat Imagine a beach. How does the temperature of the sand differ from the temperature of the water? It would take about six times as much heat to heat the water up to the same temperature of the sand because the specific heat of sand is six times greater than that of water.

Specific Heats of Some Common Materials Specific heat is the amount of heat need to raise the temperature of 1 kg of a material by 1 °C. Specific Heats of Some Common Materials Substance Specific Heat [J/(kg°C)] Water 4,184 Wood 1,760 Carbon (graphite) 710 Glass 664 Iron 450

Water as a Coolant Water, compared to most materials, has a very high specific heat. Because water can absorb large amounts of heat without raising it’s temperature it is ideal for a coolant. A coolant is a substance used to absorb heat. Examples: automobile engine and super computers.

Measuring Specific Heat To measure specific heat you use a device called a calorimeter. It can be calculated by the mass of the material, its change in temperature , and the amount of heat absorbed or released. A calorimeter uses a known mass of water to measure the amount of heat released into the water.

Section Check How are heat and thermal energy related? What is specific heat? If equal amounts of water and alcohol are heated for ten minutes, the alcohol has a high temperature after the ten minutes. What does this tell you about the specific heat of alcohol compared to that of water?