Heat and Temperature Test Review
When heat is transferred, thermal energy always moves from HOT to COLD objects.
The transfer of heat by direct contact is CONDUCTION and it occurs most easily in solids.
The transfer of thermal energy by the movement of molecules from one part of a material to another is called CONVECTION. This happens mostly in liquids and gases.
Heat transfer by RADIATION occurs when energy is transferred by electromagnetic waves. This is best seen when the sun transmits waves to Earth through empty space.
Water freezes at 0 degrees Celsius and 32 Fahrenheit. Water boils at 100 degrees Celsius and 212 Fahrenheit. (NO MATTER WHAT TEMPERATURE AT WHICH YOU START).
A THERMOMETER measures thermal energy by molecules getting farther away as it gets warmer. They spread out and rise through the tube of this device. This is a good example of THERMAL EXPANSION.
Stirring a cup of hot cocoa helps it cool by allowing the heat energy to escape.
If temperature of a glass of water rises from 5 to 10 degrees then heat energy flowed into the water.
All objects will reach thermal equilibrium at some point. Meaning that they will become the same temperature as their surroundings. This is why it takes a thermometer’s temperature a few minutes to stop changing. If you left a wool mitten, a piece of metal and a block of ice outside in 0 degree weather for a long time which would have the lowest temperature? THEY ALL WOULD BE THE SAME
A thermos works to keep your coffee warm because air slows the transfer of heat energy.
Metal chairs feel cold when you sit on them because metal is a thermal conductor and it conducts heat energy from you.
KNOW THIS FOR A FEW QUESTIONS: On a graph, a line that is going up represents adding thermal energy or an object getting hotter, a straight line represents thermal equilibrium, and a line going down represents an object cooling off.
Evaporation means when a liquid becomes a gas, Sublimation is when a solid becomes a gas.
