What is all matter composed of?
All matter is composed of continually jiggling atoms or molecules. Because of this random motion, the atoms and molecules in matter have kinetic energy. The average kinetic energy of these individual particles cause heat.
What has happened if something becomes warmer?
Whenever something becomes warmer, the kinetic energy of its atoms or molecules has increased
How can you increase the kinetic energy in matter?
It's easy to increase the kinetic energy in matter. You can warm a penny by striking it with a hammer. It's warmed because the blow causes molecules in the penny to jostle faster. When the atoms or molecules in matter move faster, the matter gets warmer.
Temperature
The quantity that tells how hot or cold something is compared with a standard
What happens physically when matter is warmed and cooled?
Nearly all matter expands when its temperature increases and contracts when its temperature decreases
What is the temperature at which water freezes and boils?
0C is the temperature at which water freezes. 100C is the temperature at which water boils. 32F is the number at which water freezes. 212F is the number at which water boils
Degrees
The gap between freezing and boiling is divided into 100 equal parts called degrees
Celsius Scale
A temperature scale with 0 as the melting-freezing temperature for water and 100 as the boiling-condensing temperature of water at standard pressure
Fahrenheit Scale
The temperature scale common in the US
Kelvin Scale
The scale used in scientific research is the SI scale. Its degrees are the same as the celsius degree and are called "kelvins".
Absolute zero
On the kelvin scale, the number 0 is assigned to the lowest possible temperature. At absolute zero, a substance has no kinetic energy to give up.
What does zero on the kelvin scale correspond to on the celsius scale?
zero on the kelvin scale corresponds to -273C on the celsius scale
In gas, temperature is proportional to what
In gas, temperature is proportional to the average kinetic energy of molecular translational motion (motion along a straight or curved path). In solids and liquids, where molecules are more constrained and have potential energy, temperature is more compli
The warmth you feel when you touch a hot surface is the kinetic energy transferred by _______ in the ________ to _______ in your ________
molecules, surface, molecules, fingers
Is temperature a measure of the total kinetic energy of all the molecules in a substance?
Temperature is NOT a measure of the total kinetic energy of all the molecules in a substance. There is twice as much kinetic energy in 2 liters of boiling water than in 1 liter. But the temperature of both liters of water are the same because the AVERAGE
Explain the direction of spontaneous energy transfer
The direction of spontaneous energy transfer is always from a warmer substance to a cooler substance. If you touch an ice cube, energy will pass out of your hand and into the ice because it's the ice that's cooler
Heat
The energy that transfers from one object to another because of a temperature differences between them
Is it correct to think that matter contains heat?
It's incorrect to think that matter CONTAINS heat. Matter contains ENERGY but not hear. Heat is energy in transit from a body of higher temperature to one of lower temperature. Once transferred, the energy is not heat anymore
Thermal Energy
Also known as internal energy. It is energy resulting from heat flow
Thermal contact
OBject or substances that are in contact with another object in which heat flows between them
How does heat flow
Heat flows according to temperature differences. That is, average molecular kinetic energy differences, not based on which substance has more molecular kinetic energy
Thermal equilibrium
After objects, in contact with each other, read the same temperature and no heat flows between them
To read a thermometer...
To read a thermometer, we wait until it reaches thermal equilibrium with the substance being measured
There is energy in many forms...
There is energy in many forms. There is rotational kinetic energy of molecules and ice due to internal movement of atoms with molecules' there is also potential energy due to the forces between atoms
Internal Energy
The grand total of energies inside a substance
A substance does not contain ____; it contains _______ _______
heat, internal energy
When a substance takes in or gives off heat, any of its energies may change...
When a substance takes in or gives off heat, any of its energies may change. Thus, as a substance absorbs heat, this energy may or may not make the molecules jostle faster
How can the amount of heat transferred be determined?
The amount of heat transferred can be determined by measuring the temperature change of a known mass of water that absorbs heat
To quantify heat, we must do what?
To quantify heat, we must specify the MASS and kind of SUBSTANCE affected
calorie
The most commonly used unit for heat. The calorie is defined as the amount of heat required to raise the temperature of 1 gram of water by 1C
What's a kilocalorie?
A kilocalorie is 1,000 calories. The heat unit used in rating foods is actually a kilocalorie, although it is referred to as the Calorie (capital C)
SI
The international system of units
What's the SI unit for all forms of energy?
Joules
How is the energy value in food determined?
The energy value in food is determined by burning the food and measuring the energy that is released as heat. To the weight watcher, a peanut contains 10 calories; To the physicist, it releases 10,000 calories of energy when burned or digested
Explain the winds in North America
The winds in the latitudes of North America are westerly. On west coast, air moves from the Pacific Ocean to the land. Because of water's high heat capacity, ocean temperatures don't vary much from summer to winder. The water is warmer than the air in the
What happens when the temperature of a substance is increased?
When the temperature of a substance is increased, its molecules jiggle faster and normally tend to move farther apart. The result is the expansion of the substance. All formed of matter expand when they're heated and contract when they are cooled. Gases t
Why do concrete sidewalks and pavement crack?
Concrete sidewalks and pavement cracks because of the contraction and expansion it experiences between summer and winter. To prevent this, the tar is laid in small sections
When must the expansion of materials be allowed?
The expansion of materials must be allowed for in the construction of structures and devices of all kinds
Expansion Joint
Gap that safely absorbs the heat-induced expansion and contraction of things like bridges, roads, sidewalks, etc., It absorbs vibrations, or to allow movement due to ground settlement or earthquakes.
Do all substances have the same capacities for storing internal energy?
Different substances have different capacities for storing internal energy. It may take 15 minutes to raise a ball to a temperature of 100C, but 2 minutes to heat a fishing pole to the same temperature
Temperature is a measure of ONLY what?
Temperature is a measure of ONLY the kinetic energy of translational motion. Generally, only part of the energy absorbed by a substance raises its temperature
Specific Heat Capacity
The quantity of heat required to raise the temperature of a unit mass by 1 degree. We can think of specific heat capacity as thermal inertia. SPecific heat capactiy is like a thermal intertia, since it signifies the resistance of a substance to change its
What is special about water's specific heat capacity?
Water has a much higher capacity for storing energy than most common materials. A relatively small amount of water absorbs a great deal of heat for a correspondingly small temperature rise.
What would happen to the countries of Europe if water did not have a high specific heat capacity?
If water did not have a high specific heat capacity, the countries of Europe would be as cold as north eastern regions of Canada
What should I do if I find it difficult to unscrew the lid of something?
The next time you find it difficult to unscrew the lid of something, let thermal expansion assist you. You can place the lid under hot water, so it will expand
Bimetallic strip
The strips of different metals, such as the ones of brass and of iron, welded or riveted together into one strip. Because the two substances expand at different rates, when heated or cooled, the strips bend. They are used in thermostats. When the room bec
Thermostat
Practical application of a bimetallic strip
What does the amount of expansion of a substance depend on?
The amount of expansion of a substance depends on its change in temperature. Liquids expand appreciably with increases in temperatures. When the gasoline tank of a car is filled at the gas station and the car is then parked for a while, the gasoline often
Why is it advisable to allow telephone lines sag when stringing them between poles in the summer?
Telephone lines are longer in the summer, when they are warmer, and shorter in the winter, when they are cooler. They therefore sag more on hot summer days than in water. If the telephone lines aren't strung enough sag in summer, they may contract too muc
How could you remove the dent out of something? such as a ping-pong ball?
You could place it in boiling water. You palce the ping-pong ball in boiling water, and you'll remove the dent
*Explain the unusual heating of ice cold water
Almost all liquids will expand when they are heated. Ice cold water, however, does just the opposite. Water at the temperature of melting ice, 0C, contracts when the temperature is increased. It continues to contract until it reaches 4C, then it expands.
*Explain the freezing of the top layer of a pond
Suppose that the greatest density of water were at its freezing point, as it is true of most liquids. Then, the coldest water would settle at the bottoms and ponds would freeze from bottom up. Pond organisms would then be destroyed in winter months. Fortu