Temperature and Heat. Temperature Kinetic energy is the energy that matter has due to the movement...

Temperature and Heat

Temperature

Kinetic energy is the energy that matter has due to the movement of that matter or within the matter

Temperature- the measurement of the kinetic energy in a sample of matter

Temperature

All matter is made of atoms or molecules.

These particles move around at different speeds depending upon temperature

The faster they move, the higher the kinetic energy, the higher the temperature

Temperature and Kinetic Energy of Water

Frozen water- low particle movement = low kinetic energy= low temperature

Boiling water- high particle movement = high kinetic energy = high temperature

Measuring Temperature

Thermometers are used to measure temperature Most contain alcohol or mercury because

they remain liquids at most temperature Thermometers- measure thermal expansion

of a substance Thermal expansion- how fast a substance

increases its volume because of particle movement

Temperature Scales

Fahrenheit- used in the United States Water freezes- 32° Water boils- 212° Body temp- 98.6°

Celsius- used around the world and in science Water freezes- 0° Water boils- 100° Body temp.- 37°

Temperature Scales

Kelvin- primarily used in astronomy Absolute zero- all particle movement

stops at 0 K Approx- -459° F Never been achieved naturally or artificially

Thermal Expansion

Most materials expand when they are heated

Most materials contract when they are cooled This is due to the speed of the particles

in the materials Think of freezing and boiling water

Thermal Expansion

Roads are built with expansion joints- so that roads and bridges have room to expand when it gets hot

Thermal Expansion of Gases

Hot air rises, cold air sinks Attic and basement during summer Hot air balloons

Heat

Heat- the amount of energy transferred between two objects that are at different temperatures

Thermal energy is always transferred from the object with a higher temperature to an object with a lower temperature Stethoscope- energy is transferred from

your back (37) to the stethoscope (20)

Transfer of Thermal Energy

Remember energy can neither be created nor destroyed

Thermal Energy is transferred in three ways Conduction Convection Radiation

Conduction

Conduction- the transfer of thermal energy between materials that are touching

Conductors and Insulators

Thermal conductors- substances that conduct thermal energy very wellMost metals are conductors- heat up quickly

Thermal insulators- substances that do not conduct thermal energy very well- heat up slower

Wood, plastic, cloth

Convection

Convection- the transfer of thermal energy by the circulation or movement of a liquid or gas Convection causes some ocean currents, the

movement of magma below the Earth’s surface and wind

Radiation

Radiation- the transfer of thermal energy through electromagnetic waves like visible light and infrared waves Can occur through particles of matter or

through space

Heat Transfer