temperature and heat in the atmosphere

heat

Heat energy is transferred between physical entities. Heat is taken in or released when an object changes state, or changes from a gas to a liquid, or a liquid to a solid. This heat is called latent heat. When a substance changes state, latent heat is released or absorbed. A substance that is changing its state of matter does not change temperature. All of the energy that is released or absorbed goes toward changing the materials state. For example, imagine a pot of boiling water on a stove burner: that water is at 100o C (212o F). If you increase the temperature of the burner, more heat enters the water. The water remains at its boiling temperature, but the additional energy goes into changing the water from liquid to gas. With more heat the water evaporates more rapidly. When water changes from a liquid to a gas it takes in heat. Since evaporation takes in heat, this is called evaporative cooling. Evaporative cooling is an inexpensive way to cool homes in hot, dry areas. Substances also differ in their specific heat, the amount of energy needed to raise the temperature of one gram of the material by 1.0o C (1.8o F). Water has a very high specific heat, which means it takes a lot of energy to change the temperature of water. Lets compare a puddle and asphalt, for example. If you are walking barefoot on a sunny day, which would you rather walk across, the shallow puddle or an asphalt parking lot? Because of its high specific heat, the water stays cooler than the asphalt, even though it receives the same amount of solar radiation.

temperature

Temperature is a measure of how fast the atoms in a material are vibrating. High temperature particles vibrate faster than low temperature particles. Rapidly vibrating atoms smash together, which generates heat. As a material cools down, the atoms vibrate more slowly and collide less frequently. As a result, they emit less heat. What is the difference between heat and temperature? Temperature measures how fast a materials atoms are vibrating. Heat measures the materials total energy.

instructional diagrams

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questions

high temperature particles vibrate more slowly than low temperature particles.

a) true

-->  b) false

which of the following has high temperature, but little heat?

a) a hot tub

b) a bonfire

-->  c) a candle flame

d) a barrel full of molten lead.

evaporative cooling works to cool a house in a hot, dry area because

-->  a) when water changes state from liquid to gas it absorbs heat.

b) when water changes state from gas to liquid it releases heat.

c) heat is radiated outward when water runs over a mesh screen.

d) heat is absorbed when water runs over a mesh screen.

the amount of energy needed to raise the temperature of one gram of material by 1.0oc.

a) latent heat

-->  b) specific heat

c) radiant heat

d) solar heat

a pot of boiling water will not get hotter than 100oc (212of). if more heat is added, the water will evaporate.

-->  a) true

b) false

when energy is released by a material, it gets warmer.

a) true

-->  b) false

if a substance has a high specific heat it means

a) it doesnt take much energy to change its temperature.

b) it takes a lot of energy to get it to change state.

c) it doesnt take a lot of energy to get it to change state.

-->  d) it takes a lot of energy to change its temperature.

why is the ocean so good at moderating temperature near the coast?

a) it has a low specific heat.

-->  b) it has to gain or lose a lot of energy to change its temperature.

c) it has a low latent heat.

d) a & b

diagram questions

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