Chapter 10 Section 1

Temperature

What is Temperature?• A measure of the average kinetic

energy of the particles in an object– The faster the particles move, the more

kinetic energy– The more kinetic energy, the higher the

temperature

Tool: thermometerworks by thermal expansion

Thermal expansion- the increase in volume of a substance due to an increase in temperature

Substance gets hotter particles move faster particles spread out

therefore substance expands

Measuring temperature

Temperature Scales• Official SI scale- Kelvin scale

– Lowest temperature is absolute zero– Never been achieved– Absolute zero is the point when all

particle movement stops– Unit is kelvin

• Fahrenheit– Not widely used in science– Units °F

• Celsius– Divided in 100 equal parts– Units~°C

Temperature conversionTo Convert: Use this equation:

Celsius to Fahrenheit °C °F

°F = (9/5 x °C) +32

Fahrenheit to Celsius °F °C

°C = 5/9 x(°F - 32)

Celsius to Kelvin °C K

K = °C + 273

Kelvin to Celsius K °C

°C = K - 273

What is Heat?Chapter 10 Section 2

Heat is a Transfer of Energy

Heat ~ the transfer of energy between objects that are a different temperature

Energy is transferred from the object with the higher temperature to the object with the lower temperature

Thermal energy ~ the total kinetic energy of the particles that make up a substancedepends on amount and temperature of the substance

Thermal equilibrium~ when both objects reach the same temperature

Conduction, Convection, Radiation• Conduction ~ the transfer of thermal

energy from one object to another through direct contact– Conductors transfer thermal energy well

• Many metals– Insulators do not transfer thermal

energy well• wood

Conduction, Convection, Radiation• Convection ~ transfer of thermal

energy by the movement of a liquid or gas

• Convection current~ circular motion of liquids and gases due to density differences

Conduction, Convection, Radiation• Radiation ~ the transfer of energy

through matter or space as electromagnetic waves– Visible light, infrared waves

The Differences Between Temperature, Thermal Energy, and Heat

Temperature Thermal Energy Heat

A measure of the average kinetic energy of the particles in a substance

The total kinetic energy of the particles in a substance

The transfer of energy between objects that are at different temperatures

Expressed in degrees Fahrenheit, degrees Celsius, or kelvins

Expressed in joules Amount of energy transferred expressed in joules or calories

Does not vary with the mass of a substance

Varies with the mass and temperature of a substance

Varies with the mass, specific heat capacity, and temperature change of a substance