Chapter 6: Thermal Energy

How do you calculate from degreed C to degrees F?

F= (degrees C x 1.8) + 32 degrees

Maple sap boils at 104 degrees C. At what F temp. does the sap boil?

F= 219.2 degrees F

When does water freeze and boil on the celsius scale?

FREEZE: 0 degrees C BOILS: 100 degrees C

When does water freeze and boil on the Kelvin scale?

FREEZE: 273 K BOILS: 373 K

When does water freeze and boil on the Fahrenheit scale?

FREEZE: 32 degrees F BOILS: 212 degrees F

How could you increase the kinetic thermal energy of a liquid?

If heat is applied to a liquid, molecules move faster. Therefore, the kinetic energy and temperature increases.

How does a thermostat work?

It has a bimetallic coil made of 2 types of metal that expand and contract at different rates; the coil curls and uncurls, depending on the air temp, to move a switch that controls a furnace.

Explain a bulb thermometer.

It has a liquid that expands and rises in a glass tube when its temp. goes up; the liquid contracts and its level drops when the temp. goes down.

Explain an electric thermometer.

It measures the resistance in an electronic circuit and converts this measurement into a temperature.

Suppose a friends tells you he has a temp. of 38 degrees C. Your temp. is 37 degrees C. Do the particles that make up your body or your friends body have a greater kinetic energy? Explain.

My friend's body has a greater kinetic energy because the greater the temperature, the greater the average kinetic energy of the particles.

What is the only way for thermal energy to travel from the Sun to Earth? Why?

Radiation. This is bc radiation is the only way for thermal energy to travel through the vacuum of empty space.

Relate temperature to the average kinetic energy in a material.

Temperature is the average kinetic energy in a material.

What is radiation?

The transfer of thermal energy from one material to another by electromagnetic waves

What's the difference between thermal energy and heat?

Thermal energy is the sum of the kinetic energy and the potential energy of the particles that make up a material. Heat is the movement of thermal energy from a warmer object to a cooler object.

Does radiation occur in solids, liquids, and gases?

Yes.

Does water have a high specific heat?

Yes. And it's good for cooling things.

What is a fridge?

a device that uses electric energy to pump thermal energy from a cooler location to a warmer location.

What is a thermal conductor? What is a good example of a thermal conductor and why?

a material through which thermal energy flows easily. metals are good thermal conductors bc they have electrons that move easily, so they often collide w/ other particles and transfer kinetic energy easily.

What is a thermal insulator? What is a good example of a thermal insulator and why?

a thermal insulator is a material through which thermal energy does not flow through easily. a good example would be non-metals, rubber, or cloth because their electrons do not move easily, so few collisions occur between electrons and atoms of insulators.

What is used to measure temperature?

a thermometer

In which device would you find a fluid a coolant? a. thermostat b. fridge c. heating appliance

b. fridge

In which material would thermal expansion and thermal conduction be most noticeable? a. the water in a cup b. the air in a balloon c. the metal parts of a car

b. the air in a balloon

Why does convection happen?

bc of differences in temp due to thermal expansion and thermal contraction in different parts of the material.

How is thermal energy being transferred between the water and the thermometer?

by conduction

How can thermal energy be transferred from one object to another if the objects are not in contact?

by radiation only

Which device is a heating appliance? a. computer b. cell phone c. clothes iron

c. clothes iron

on which temp. scale does water freeze at 0 degrees?

celsius

In an internal combustion engine, what form of energy is converted to thermal energy?

chemical energy

Which sequence describes the energy transformation in an automobile engine?

chemical to thermal to mechanical

What are the currents of warm and cool air in earth's atmosphere called?

convection currents

What is convection and what does it occur in?

convection is the transfer of thermal energy by the movement of particles from one part of a material to another. it occurs in fluids (liquids & gases)

What are heating appliances?

devices that convert electrical energy into thermal energy; some examples are clothes irons and coffee makers

What is the movement of thermal energy from a warmer object to a cooler object?

heat

Which increases the kinetic energy of the particles that make up a bowl of soup?

heating the soup for 1 min on a stove

do thermal insulators have a high or low specific heat?

high

What is the function of the coolant in a refrigerator?

it moves thermal energy from inside the refrigerator to outside

Particles that make up matter have what type(s) of energy?

kinetic and potential energy

forms of energy that make up thermal energy?

kinetic and potential energy

Scientists describe temperature in terms of...?

kinetic energy

What is the energy of motion?

kinetic energy

Do thermal conductors have a high or low specific heat?

low

How is mechanical energy different from thermal energy?

mechanical energy is a property of the particles that make up an object

When does conduction stop?

not until the thermal energy of all the particles that are in contact are equal

What is the energy stored in the interactions between objects or particles?

potential energy

thermal energy from the Sun transfers to the Earth by...

radiation.

Thermal energy describes the energy of the particles in...

solids, liquids, and gases

What represents the average kinetic energy of the particles that make up a material?

temperature

What is specific heat?

the amount of thermal energy required to heat 1 kg of material by 1ºC

What is a crank-shaft?

the mechanical energy that moves a car

the more mass...

the more energy required

What is a convection current?

the movement of fluids up and down in a cycle bc of convection

What happens to the temp. of a water cup when the average kinetic energy of the particles decreases?

the temp. decreases

What is conduction?

the transfer of thermal energy between materials bc of collisions between the particles

What is thermal contraction and why does it occur?

thermal contraction is a decrease in a material's volume when the temp is decreased. it occurs bc particles get closer together as their kinetic energy decreases.

Because kinetic energy is being transferred what is also being transferred?

thermal energy

People convert many forms of energy into what type of energy?

thermal energy

What do all objects radiate?

thermal energy

What is the sum of the kinetic energy and potential energy in the particles that make up the material?

thermal energy

The particles in a melting ice cube change from a solid to a liquid, but their temp. does not change. As the ice melts, the particles gain...

thermal energy and potential energy

What happens to the red liquid inside the thermometer as the water in the beaker heats up?

thermal expansion

What is thermal expansion and why does it occur?

thermal expansion is an increase in a material's volume when the temp is increased. it occurs bc particles spread out as their kinetic energy increases.

What's absolute 0?

(0 K) At this temp., the particles in a material would not be moving and would have no kinetic energy.

How do you calculate from degrees F to degrees C? (formula)

(degrees F - 32 degrees) ---------------------------------- 1.8

The freezing point of a solution of salt water is found to be 25 degrees F. What is this in degrees C?

-3.9 degrees C

In an automobile engine, only about ______ percent of the ____________ energy of the fuel gets converted into ________________ energy; the rest becomes heat, which causes the car's ________ to become hot.

1. 20 percent 2. chemical 3. mechanical 4. engine

When particles that have the same kinetic energies _______, the particles that have a _________ kinetic energy transfer energy to particles that have __________ kinetic energy; in this way, the average kinetic energy, or ________, of the material changes(increases).

1. collide 2. higher 3. lower 4. temp

In the bottom of a fridge, there is a _____________ that forces the coolant into a smaller space, which increases the _____________ energy of the coolant.

1. compressor 2. thermal

The __________ releases thermal energy into the _____ around the fridge. This change causes the coolant to become a _________, and then the cooling cycle begins again.

1. coolant 2. air 3. liquid

A __________, which is a fluid, flows through pipes that surround the compartments of the fridge; ___________ energy is transferred from the inside of the fridge to the coolant, which is why the fridge stays cold.

1. coolant 2. thermal

A fridge uses _______________ energy to move the __________ through fridge pipes.

1. electrical 2. coolant

In a car engine, a spark ignites a fuel-air mix, which __________ and pushes a piston down; this motion turns the crankshaft.

1. expands

Starting as a liquid, the coolant passes through an _____________________, changes into a gas, and becomes __________.

1. expansion valve and cools 2. vapor

A material with a ________ temp. has particles that have a greater kinetic energy.

1. greater

Particles whose average kinetic energy is large are moving at a ________ kinetic energy than a material w/ a _____________ temperature.

1. greater 2. cooler

A material with a ________ temp. has particles that have a lower kinetic energy.

1. lower/cooler

convection currents cause a _________ in Earth's climate.

1. pattern

A moving soccer ball that has been kicked into the air has kinetic energy and _________ energy; together they make up the _____________ energy of the ball.

1. potential 2. mechanical

Thermal energy can be transferred from one object to another by __________, ____________, and _______________.

1. radiation 2. conduction 3. convection

there will always be the _______ amount of energy when referring to specific heat

1. same

The rate at which heating occurs depends on the difference in ______________ between 2 objects; the greater the difference, the _______ heat is transferred.

1. temperatures 2. more

What are the steps involved in an internal combustion engine?

1. the intake valve opens as the piston moves downward, drawing a mixture of gas and air in the cylinder 2. the intake valve closes as the piston moves upward, compressing the fuel-air mix 3. A spark plug ignites the fuel-air mix. As the mix burns, hot gases expand, pushing the piston downward. 4. as the piston moves up, the exhaust valve opens, & the hot gases are pushed out of the cylinder.

The coolant removes the _________ energy from the inside of the fridge, so the fridge cools off.

1. thermal

2 materials can have the same temp but different _________ energy. For example, ice and water have the same average kinetic energy, but liquid water has _______ thermal energy b/c its particles have greater potential energy than those of ice.

1. thermal 2. more

All objects have ________ energy, but heating only occurs when ___________ energy is transferred from one object to another object.

1. thermal 2. thermal

computer and cell phones produce ________ energy.

1. waste

The boiling point of ethanol in 78.4 degrees C. What is this in degrees F?

173.1 degrees F

What is a thermostat?

A device that regulates the temp of a system

What is a heat engine?

A machine that converts thermal energy into mechanical energy.

Explain how 2 of the devices you read about in this chapter could be used in one appliance.

A thermostat and a heat pump can both be used in a fridge. For example, the thermostat regulates the temperature of the fridge while the heat pump transfers the heat from inside the fridge to the outside so the inside of the fridge stays cool.

Explain how a thermostat uses electrical energy, mechanical energy, and thermal energy.

A thermostat has a bimetallic coil made of 2 types of metals that expands and contracts at different rates; the coil curls and uncurls, depending on the air temperature, to move a switch that controls a furnace.

Heating occurs until when?

All substances that are in contact have reached the same temp.

Explain how an internal combustion engine works.

An internal combustion engine, that can be found in moving vehicles and lawn mowers, converts chemical energy into thermal energy into mechanical energy.

Suppose you pointed a hair dryer at a thermostat and turned on the hair dryer. What would happen?

Blowing a hair dryer at the thermostat would cause the air around it to become warmer. Therefore, after the room warms, the thermal energy in the air causes the bimetallic coil to uncurl slightly. This moves a switch that turns off the furnace.