Physics Heat Test Flashcards
1
Q
What is temperature?
A
- A measure of the quantity of heat.
- How much heat something has.
2
Q
Cold does not exist. What is it simply?
A
It is a lack of heat.
3
Q
What happens to molecules/matter when temperature increases? What happens to the object?
A
Molecules move faster, and the object begins to expand.
4
Q
What happens when temperature decreases?
A
The molecules slow down, and condense closer together.
5
Q
As water vapor evaporates, it gets higher and higher and the temperature decreases. What does it condense into?
A
Clouds
6
Q
What happens to molecules in cooler and hotter temperatures?
A
- In cooler temperatures the molecules are more compact.
- In hotter temperatures the molecules are more spread out.
7
Q
What do we call the American temperature scale that ranges from 32 degrees freezing and 212 degrees boiling?
A
Fahrenheit
8
Q
What does the range of the temperatures for the American scale based on?
A
Always based on the freezing point and boiling point of water.
9
Q
Where do we typically exist in degrees body wise?
A
In the high 90’s.
10
Q
What will decrease the freezing point of water as well as decreases the boiling point as well?
A
Salt
11
Q
What is the metric scale called and what is its range?
A
Celcius: 0-100
12
Q
What is the scientific heat scale called?
A
Kelvin
13
Q
In the Kelvin scale, we start at 0 degrees, but what do we call it instead? What is its equivalent in Celcius?
A
Absolute Zero; -273
14
Q
When we feel heat we are actually feeling what?
A
We are actually feeling a transfer of energy.
15
Q
What happens when you touch a hot stove?
A
Energy (heat) is entering your body.
- This is what we feel when we touch something and it feels hot.
16
Q
When you touch something that is cold what is happening?
A
Heat is leaving your body.
17
Q
Heat always flows in what direction just like water?
A
- Always flows downhill.
- Heat always goes from a high temperature to a low temperature.
18
Q
What is thermal energy?
A
When heat transfers from either leaving our body, or going into our body.
19
Q
When a hammer strikes a penny what will happen to the penny?
A
The molecules will speed up, and it will feel hot after feeling cool at the start.
20
Q
What is specific heat?
A
The capacity of something to hold energy
21
Q
What is thermal equilibrium?
A
Heat is no longer only leaving one thing, but heat is going back and forth at an equal rate.
22
Q
What does a thermometer actually do?
A
It tells us its temperature.
23
Q
When does the liquid (mercury) in the thermometer stop moving up and down?
A
When it reaches thermal equilibrium.
24
Q
What are the 2 requirements to measure heat, or to figure out how much heat something has in it?
A
- Mass
- Material
25
What is the common unit for a measurement of heat in food? In physics?
calorie (c); Joule (J)
26
What is the common unit for a measurement of temperature?
Degrees
27
Calories are not neccessarily an indication of health. What are they actually an indication of?
They are an indication of how much heat that particular thing has.
28
What do BIG C Calories stand for?
BIG C Calories are called kilocalories (C).
29
How many calories are in a kilocalorie?
1,000 calories are in a kilocalorie.
30
What is heat a type of?
Heat is a type of energy.
31
1 calorie equals how many joules?
1 calorie = 4.184 joules
32
What is a calorie?
Is the amount of heat required to raise 1 gram of water by 1 degree Celsius.
33
What happens with the specific heat of crust vs. filling?
The crust will change heat faster than the filling.
34
What happens with the specific heat of dough vs. sauce?
The sauce will have a bigger effect, because both are 2 different materials and have 2 different specific heats.
35
What happens with the specific heat of foil vs. a pan?
The pan will maintain/have more heat by holding more in than the foil.
36
What happens with the specific heat of tile vs. carpet?
When you step out of bed in the morning and step on carpet it is no big deal. When you step on tile though, you feel cold. They are different materials, and hold their heat differently.
37
What is the common idea of specific heat? In other words, we are dealing with what?
- The higher the specific heat the less likely it is to change.
- Thermal Inertia
38
What is Thermal inertia?
- How likely something is to stay the same temperature.
- How much energy we have to put in it to change it.
- The higher the specific heat, the stronger its thermal inertia, the less likely it is to change.
39
Does have water have a high specific heat?
water
40
Water resists temperature changes. Therefore, can it be a good cooling agent?
Yes, water can be a cooling agent.
41
Can water also be a good heating agent?
Yes, water can also be a good heating agent.
42
What is strongly regulated with waters' specific heat?
Climate
43
What is a good example of climate being strongly regulated with waters' specific heat?
The state of California being cool in the summer with the water being cold, because the heat is being pulled out to sea. When it is the winter time however, the water is still cold, but the specific heat from the water can give it to the land to warm up the land.
44
When is water the most dense
4 degree C
45
Why does ice float?
Ice floats because it is less dense.
46
What is thermal expansion?
Materials expand at different rates.
47
Which contracts and expands more readliy, asphalt or concrete?
Asphalt
48
What are bimetallic strips?
You have strips that are made of 1 metal on one side, and another metal on the other side.
49
How do thermostats work?
- Thermostats work by using bimetallic strips. It is a big coil where one side of the metal is one material, and the other side of the metal is another material, and they are coiled up.
- When the heat goes up, the 2 metals expand at different rates, and the coil hits the edge where it hits a switch to turn on the AC. For heat, the coil would hit the edge where it hits a switch to turn off the heat.
- When it gets cooler, the 2 metals condense, and the coil hits the edge where it flips a switch to turn off the AC. For heat, the coil would hit the edge where it hits a switch to turn on the heat.
50
Does wood have a high or low SH
low
51
Does rubber have a high or low SH
High
52
Does leather have a high or low SH
High
53
Does tile have a high or low SH
Low
54
Does sand have a high or low SH
Low
55
Does metal have a high or low SH
low
56
Does iron have a high or low SH
low
57
How many degrees are between the melting point of ice and boiling point of water on the Celsius scale? Fahrenheit scale?
- 100 degrees
- 180 degrees
58
What does it mean to say that a material has a high or low specific heat capacity?
How much energy it can store and how easy it is to change its temp
59
Why do lakes and ponds freeze from the top down rather than from the bottom up?
As the top water cools down, it starts to get heavier/more dense when it reaches 4 degrees, and it starts to sink. When each level hits 4 degrees and sinks the water is constantly circulating until basically the whole body of water is 4 degrees Celsius. When the water can't get any colder and gets to 0 degrees, the water freezes at the top.
60
Calculate the number of calories of heat needed to change 500 grams of water by 50 Celsius degrees.
Q = mcΔT
Q = (500 g) (1 cal/g C) (50 C)
Q = 25,000 cal
61
Calculate the number of calories given off by 500 grams of water cooling from 50 degrees Celsius to 20 degrees Celsius.
Q = mcΔT
Q = (500 g) (1 cal/g C) (30 C)
Q = 15,000 cal
62
A 30-gram piece of iron is heated to 100 degrees Celsius and then dropped into cool water where the iron's temperature drops to 30 degrees Celsius. How many calories does it lose to the water? (The specific heat capacity of iron is 0.11 cal/g degrees Celsius.)
Q = mcΔT
Q = (30 g) (0.11 cal/g degrees C) (70 C)
Q = 231 cal
63
If you drop a hot rock into a pail of water, the temperature of the rock and the water will change until both are equal. The rock will cool and the water will warm. Does the same principle hold true if the rock is dropped into a large lake? Explain.
This will still happen, but the water will not grow as hot because of its great quantity. The rock temperature will become more cold than it would in the bucket.
64
What is conduction?
- Is heat transfer within a material.
- Can be in between materials as well.
65
What is going to make something one of the best conductors?
- The best conductors are going to be those that have electrons that are easy to lose.
- The best conductors that will transfer heat within them are going to be those things that have electrons that jump around very easily.
66
What are the best conductors?
The best conductors are metals (In order: Silver, gold, aluminum iron)
67
Do conductors have a high specific heat or a low specific heat? What is an example from the answer to the first question?
low
68
Do insulators have a high specific heat or a low specific heat?
- Insulators have high specific heat.
- Insulators don't want to change their temperature easily. It takes a lot of heat in order to change it.
69
What are we trying to do when we insulate our homes?
- Trying to keep the heat inside during the winter.
- Trying to keep heat out during the summer.
70
What is convection?
Heat transfer in a fluid.
71
The wind blows toward where at night? The wind blows toward where during the day?
- At night, the wind blows toward the ocean.
- During the day, the wind blows toward the land.
72
High temperatures are going to be associated with high energy. What is an example? What length of wavelengths do they have?
- Gamma rays
- Wavelengths are short.
73
Short wavelengths have high what?
Short waves have high temperatures.
74
Low temperatures are going to be associated with low energy. What length of wavelengths do they have?
Wavelengths are long.
75
What colors absorb lots of energy?
Dark Colors
76
What colors are good reflectors?
light Colors
77
What is emission?
Giving off heat.
78
Good absorbers are also good what?
Good absorbers are good emitters.
79
What 2 things matter to be a good absorber as well as a good emitter?
The material does matter as well as color.
80
What things do not emit well?
Reflective things do not emit well.
81
What is Newton's Law of Cooling?
The larger the difference between objects temp. the faster they will reach equilibrium
82
Why are materials such as wood, fur, feathers, and even snow good insulators?
They are good insulators because they have many air spaces. Air is a good insulator.
83
Why does a good absorber of radiant energy appear black?
Because it doesn't reflect any light, but instead absorbs it.
84
Is a good absorber of radiation a good emitter or a poor emitter?
It is a good emitter.
85
What do phase changes involve?
Change involves a transfer of energy.
86
Evaporation is considered a what type of process?
Is considered a cooling process.
87
Condensation is considered a what type of process?
Is a warming process.
88
Boiling is considered a what type of process?
Also a cooling process.
89
What raises the boiling point where temperatures also get higher?
The pressure.
90
Freezing is considered a what type of process?
Is a warming process.
91
What happens during equilibrium?
Condensation and evaporation are happening at the same rate.
92
Can boiling and freezing happen at the same time?
yes
93
What does regelation mean?
Regelation is when melting and freezing happen at the same time.
94
What happens with energy when it is being added?
Melting
95
Boiling water is a good example of what?
Convection
