Temperature and Thermal Energy Chapter 10 Section 1

What is Temperature? You need a scale to measure temperature accurately – hot and cold are relative. Temperature is a measure of the average kinetic energy of the individual particles in an object. Ex: hot cocoa has more kinetic energy and higher temperature than cold chocolate milk Temperature and Kinetic Energy Particles are always in motion and have kinetic energy. The faster the particles are moving, the more kinetic energy they have. Average Kinetic Energy of Particles Since temperature is the average KE of the particles, it does not depend on the amount of substance you measure.

Draw the diagrams below into your notes. Label the picture with the highest amount of energy and the picture with the lowest amount of energy. Label the picture with the highest temperature and the picture with the lowest temperature.

Measuring Temperature Using a Thermometer Thermometers can measure temperature by using a property called thermal expansion – the increase in volume of a substance because of an increase in temperature. As temp. increases, particles move faster and spread out, and the substance expands. Most common substances used in thermometers – mercury and alcohol.

Temperature Scales Fahrenheit Scale Celsius Scale Kelvin Scale In the U.S. (though NOT in science class!), the most common temperature scale is the Fahrenheit Scale. Water freezes at 32 ºF and boils at 212 ºF. Celsius Scale The temperature scale used in most of the world is the Celsius scale. Water freezes at 0 ºC and boils at 100 ºC. Kelvin Scale The temperature scale commonly used in physical science is the Kelvin scale – which has units that are the same size as those on the Celsius scale. The units are called kelvins (K). The lowest temperature possible is -273 ºC, or 0 K and is called absolute zero.

Section 10-2 pgs. 280-281 Transferred Thermal Energy Heat is the thermal energy transferred between objects that have different temperatures. Thermal energy always flows from a ___ object to a ___ object. Why do metal objects feel cool to us? Heat and Thermal Energy Thermal energy is the total kinetic energy of the particles of a substance. Thermal energy is measured in joules. Thermal energy depends on the amount of the substance

Draw the diagrams below into your notes. It is possible for the containers below to have the same temperature and the same thermal energy. It is possible for the containers below to have different temperatures but the same thermal energy. It is possible for the containers below to have different temperatures and different thermal energy.