Heat

poor conductor

air

why do different metals conduct heat different rates

different materials have different conductivites

Material thats good insulator

Plastics and rubber. It is for this reason that electrical wires are coated to make them more safe to handle.warm clothing; wool socks

Boiling

Bubbles of vapor escape from a liquid as a result of heating.

Insulation

Preventing heat from flowing in or out of a material.

transfer of energy

how energy moves; happens 3 ways: convection, conduction and radiation

examples of radiation

A person placing their cold hands over a warm fire; A person placing their hand over a hot burner; Lying out in the sun to get a tan; the sun makes you feel warm; the roof of your car gets hot in the sun; the pavement gets hot on a sunny day

example of conduction

A pot sitting on a hot burner; Touching a metal spoon that is sitting in a pot of boiling water; Using a heating blanket to get warm; tin cup gets hot when you pour coffee into it; meat is heated in a frying pan; you cook a hotdog over a campfire; the outside of a bowl of soup gets hot;

cloudy days

Clouds reflect the sun's heat away from the Earth, thus it makes the day cooler

3 ways Heat energy can be transferred

Conduction, Convection, Radiation

three main types of heat transfer

Conduction, convection, radiation

how fluids move

Cooler, more dense, fluids sink through warmer, less dense fluids. In effect, warmer liquids and gases rise up. Cooler liquids and gases sink.

most conductive to least conductive metal

Copper, Aluminum, Brass, Steel

describe transfer of heat in radiation

Energy leaving in the form of an electromagnetic wave (such as light). is the slowest form, but it is impossible to stop; from the Sun to the Earth's atmosphere

Potential Energy

Energy stored in an object or material.

how does ice cool a warm drink

Heat is a measure of molecular activity: the faster a thing's molecules move, the more heat that substance contains. And because everything is made of molecules, and molecules are in constant motion, everything contains at least some heat. As we know, ice is colder than room temperature water. Because ice molecules move slowly and cluster tightly together, they produce a relatively low amount of heat. When ice is placed in a glass of water whose molecules are moving at a greater rate, the ice begins to absorb energy, because heat always travels from regions of relative warmth to colder areas in order to equalize temperatures. In other words, ice absorbs heat from the water. As the water molecules lose energy, they begin to slow down, and consequently to cool. So, it's kind of the opposite of what we might think: when we put ice in water, the ice doesn't give its cold to the water, it takes heat from the water.

example of convection

How the inside of a greenhouse works; Putting your wet shoes on a floor vent to dry them faster; Macaroni rising and falling in a pot of boiling water; it produces wind; you keep your window open for ventilation; heat is transferred in water by currents; primary method of heat transfer in a fluid; pinwheel over a candle starts to spin as a result of air movement; smoke and hot air go up a chimney;

Thermal Expansion

Matter expanding when its temperature is raised.

So, is it temperature that makes you so hot?

Not exactly. Temperature is only the measure of heat. All objects have heat, some more and some less. The sand absorbs the energy from the Sun and so does the ocean water, but each does so in a different way. The sand absorbs energy more quickly while bodies of water absorb it more slowly. This explains why the sand is extremely hot at noon while the ocean water is relatively cool. Heat is a form of energy that an object has when its atoms and molecules move.

Why Metals Feel Cool to the Touch at Room Temperature

Room temperature is cooler than human body temperature. Heat is ONLY noticed when there is a transfer! Metals quickly conduct heat from your body throughout the metal (since it is taking heat, it feels cold). Wood and plastic don't conduct heat quickly, so not as much is taken from your skin. Good insulators normally have a lot of space for air, because gases don't conduct as well as solids.

difference between heat and termperature

Temperature is only the measure of heat. All objects have heat, some more and some less. The sand absorbs the energy from the Sun and so does the ocean water, but each does so in a different way. The sand absorbs energy more quickly while bodies of water absorb it more slowly. This explains why the sand is extremely hot at noon while the ocean water is relatively cool. Heat is a form of energy that an object has when its atoms and molecules move.

Condensation

The changing of a gas to a liquid.

Freezing

The changing of a liquid (water) to a solid (ice cube).

Evaporation

The changing of a liquid to a gas

Vaporization

The changing of a liquid to a gas.

Melting

The changing of a solid (ice cube) to a liquid (water).

Kinetic Energy

The energy of a moving object; energy of motion

Why is it windy at the seaside?

The land is warmer than the sea. The land warms the air above it, and it rises. The cooler air from the sea moves into to take the place of the warm air that has risen.

why doesn't a balloon filled with water pop when heated with a flame

The reason a balloon filled with air pops when you put it over a flame is because the rubber of the balloon gets very hot and weak and then breaks. When you fill a balloon with water instead of air, the water absorbs most of the heat, so the rubber doesn't get very hot.

Convection and Radiation

The sun radiates heat in the form of light toward the planet. This heats the surface, which conducts heat to the air it touches. The hot air expands and begins to rise. Cooler air fills the void the hot air left. The air begins to circulate. The circulation is convection; light (energy) is radiation.

why sitting under an umbrella at the beach keeps you cooler

The umbrella absorbs the Sun's radiant energy and conducts heat through the metal rod into the sand, just as a lightning rod deflects a bolt of lightning from a house. The heat in your beach umbrella rod travels by conduc-tion; the molecules inside the rod increase their energy of motion. As you sit on the beach, the sand absorbs sun-light and is also a pretty good conductor of heat. If one part of the sand is heated by the Sun, a direct source of heat, the neighboring parts will also become heated.

Why are gases poor conductors

Their particals are so far apart

What affects whether a substance is a good or poor conductor

how much energy is required to change the temperature of the substance by certain amount

describe transfer of heat in convection

Through a circulation of fluid; by physical movement of the heated substance itself

Why use a blanket when you are cold? Do you keep the cold out?

What blankets (and coats, and sleeping bags) do is slow down heat transfer, which prevents your body heat from being lost to the air around you. That allows your own body heat to keep you warm. Cold air tries to carry your body heat away. Blankets form a barrier between your body and that cold air. Since heat doesn't tranfer through the blankets very well, they keep the heat from getting out. The colder the surroundings are, the more insulation you need to keep your body heat from escaping too fast. As long as you're bundled up well enough, your own body heat can keep you warm even in very cold situations. Now, this only works because you're generating heat. If you were to put a blanket around something that generates heat (say, a car engine, or a light bulb), those things would heat up, even in cold weather. In fact, they could heat up enough to be dangerous, so don't try that. But if you wrap a blanket around something that doesn't generate any heat (like a piano), it won't do much good. The blanket doesn't create any heat, it just keeps the heat you're already creating inside.

How does heat move along a metal bar?

When something is heated, its atoms vibrate. If one end of a metal bar is heated, the atoms at that end vibrate more than the atoms at the cold end. The vibration spreads along the bar from atom to atom. The spread of heat in this way is called conduction. Metals are good conductors of heat.

how heat in air transfers by convection

When the air around you is heated, the lighter, warmer air rises, while the colder, denser air sinks. The uneven distribution of heat creates more air currents. Remember: Heat is all around you; it's transferred in three ways.

describe transfer of heat in conduction

When the two objects actually touch. This is the best method.

what happens when you get sun at the beach

Your body absorbs the radiation and transforms it to heat energy. Not all the energy is absorbed, though. When you do absorb this heat, the energy of your body increases and you feel hotter.

how can a boiling pot of water on a stove describe conduction, convection and radiation

When you put the pot on the stove, the heat from the stove is somehow getting to the pot, which gets hot. The pot and the stove are obviously in contact with each other. Therefore conduction plays a role here. If you have an old pot, with a warped bottom, it will heat up slower, because the contact surface between pot and stove is smaller. The air above the stove is heated and because it is a gas, moves upward. This is convection. The bottom of the pot and the surface of the stove are not 100% flat. That's why there will be little pockets of air underneath the pot, even if you place it on the stove. If you heat up the stove as much as you can, it will glow red. This is a visible sign of radiation. I'd assume that even if not visibly glowing, the stove radiates heat, too. In those areas where the stove and the bottom of the pot are not in contact, radiation transports heat from the stove to the heat. As you can see, all 3 kinds of heat transfer are involved. Conduction certainly does the most part, which is why you want to have pots with flat bottoms, to make best contact with the stove.

why does steel feel cooler than wood?

While things made of different materials may be at the same temperature, you experience them as warm or cold when you touch them. In general, metals feel colder than many other materials. As a result, things made from steel feel colder than wooden items. Even when these items have been in the same room and have the same temperature, you feel them differently because of the nature of the materials and the characteristics of the items.When two things with different temperatures touch, heat flows from the warmer item to the colder one. The effect of the heat flow is to warm up the cold item and cool down the warm one. Some materials conduct heat very well, the flow happens quickly and the warm item cools off rapidly. Other materials don't allow the heat to flow, and the two items tend to stay at their respective temperatures. metal FEELS colder than wood if they're both at room temperature. That's because metal conducts heat much better than wood does. Since your hand is hotter than room temperature, both the metal and the wood conduct heat away from it. Since the metal conducts better, that cools your hand faster, and that's what you feel. By the same token, if the metal and the wood are hotter than your hand, the metal will feel hotter than the wood. How well a material conducts heat is called its conductivity. Steel has a high conductivity and conducts heat very well. Wood has a low conductivity and blocks the heat flow. When you touch steel, your skin is at body temperature while the steel is at room temperature, about 70 degrees Fahrenheit. Heat flows quickly from the warm skin to the highly conductive steel. Your skin rapidly cools off and feels cold. When you touch wood, the wood doesn't conduct heat very well and blocks the flow. Your skin doesn't cool off and doesn't feel cold.

thermos

a container that is capable of keeping hot items hot and cold items cold. You probably had a cheap one when you were younger in your lunchbox. You can buy better ones that keep beverages hot or cold much longer. A thermos (or a cooler or even an insulated cup) works by preventing transfers of heat! Good ones have a vacuum (nothing) in between the jars. Cheap ones have Styrofoam in between.

Insulator

a substance that does NOT transfer energy easily and are poor conductors; plastic foam and wood; — This mainly deals with the movement of electrons.

Conductor

a substance that transfers energy easily; materials that allow heat to quickly pass throughout the material (such as metals). Metals have a "sea of electrons" that allows for quick heat transfer.

temperature

average motion of the atoms and molecules that we sense

why all atoms have thermal heat energy

because the atoms or molecules that make matter are in constant motion

how is energy transferred in radiation

by electromagnetic radiation

how does heat energy get from the sun to the earth

by radiation; no particles between the sun and earth so it can't travel by conduction or convection

how is energy transferred in convection

by the mass motion of molecules (movement)

effect of Cloudy nights on temperature (heat)

clouds form a blanket which keeps the heat from escaping back into the atmosphere. The heat stays in keeping us warmer.

heating of the earth

convection; moves about the planet heat gained by conduction and radiation from the sun; isn't even

Material thats a good conductor

cooking Pans, metal

volcanoes

created by the Earth from some of the heat from the sun

Contract

decreasing the size of an object by losing thermal energy

direction of heat transfer in conduction

from hotter object to cooler object

effect of Clear nights on temperature (heat)

heat from the Earth is able to escape back into the atmosphere;cooler nights

conduction

heat transfer by molecules or objects touching; transfer of energy from one object to another through direct contact;heat transfer through direct contact; takes place when objects have different temperatures and are in direct contact; Molecules of energy travel through a solid.

convection

heat transfer through gas or fluid, usually currents; Transfer of energy by the flow of a liquid or a gas; the transfer of heat by the actual movement of warmed energy in a gas or liquid by movement of currents;can take place only in liquids and gases; requires motion of molecules like air or water to move heat; main driving force for the transfer of heat between air masses;

radiation

heat transfer through space or electromagnetic waves; only way heat is transferred that can move through the relative emptiness of space;sunlight is a form of this that brings heat to our planet without the aid of anything; causes some of the Earth's heat to be lost back into space; energy is transferred as electromagnetic waves, such as visible light and infrared waves; does NOT require physical contact and does NOT require a medium to travel; it is the only type of energy that transfer that travels in waves.

explain how expanding and contracting correlates with heat

increasing molecular motion (adding heat) causes most substances to expand, while decreasing molecular motion causes most substances to contract.

Expand

increasing the size by heating an object

Temperature

measure of the average kinetic energy of the individual particles of the substance

good conductor

metal

energy transfer

movement of heat from one substance to another

effect of clear days on temperature (heat)

no clouds to reflect the sun's heat away from the Earth; day is warmer

Radiation does not require

physical contact

thermal energy

produced by the total energy of the particles that make up an object

explain making popcorn as radiation, conduction, and convection

radiation- heating through waves- popping in microwave using electromagnetic waves conduction- heating through solid- popping in a pan on the stove convection- heating through liquids or gases- popping in an air popper

describe transfer of heat energy when you take a bath

start with warm bath; as water gets cooler, bathroom air gets warmer until both are the same temperature - heat of bath water is transferred to bathroom air. Heat moves from one substance (water) to another (air) and it moved from warm to col.

Solid, liquid, gas

states of matter, movement between governed by gaining or losing thermal energy; Movement of molecules depends on whether they have gained or lost thermal energy

Thermal energy-

sum of the kinetic energy of ALL of the particles in a substance

Specific heat of any substance is

the amount of energy required to raise the temperature; it's a physical property

heat energy

the energy that flows due to temperature differences;always transferred from warmer to cooler substances

Heat

thermal energy moving from a warmer climate to a cooler climate

Thermal Conduction

transfer of energy as heat through a material

conduction, convection, radiation

ways to heat the atmosphere

when does heat transfer stop

when the two substances are at the same termperature

how is energy transferred in conduction

within a substance by direct contact