Answers to 12-2 Reinforcement Worksheet
1. radiation, conduction, convection
2. Celsius, Fahrenheit
3. weather
4. Thermal energy is the total amount of energy of all the atoms that make up a material. Heat is
thermal energy that moves from a warmer object to a cooler one.
5. Temperature measures the average kinetic energy (molecular motion) of all the atoms in a sample.
6. Thermal energy is not related to the kinetic energy of an object but only to the kinetic energy of the
atoms that make up that object. Thermal energy is the total amount of energy (potential and kinetic)
of all the atoms within an object.
7. the sun, microwave, or solar cooker
8. Conduction is the transfer of kinetic energy from one molecule to another.
9. Convection is the transfer of thermal energy by the movement of molecules from one place to
another in a gas or liquid.
Homework: 1, 2, 3 on page 337
1. A hot-air popper uses convection to transfer thermal energy.
A microwave uses radiation to transfer thermal energy.
A skillet on the stove uses conduction to transfer thermal energy.
2. Temperature is the measure of average kinetic energy (molecular motion) in the cups of tea.
Hot tea has a greater temperature than the colder tea because its molecules have greater kinetic
energy.
Heat is the movement from a warmer area to a colder area. A hot cup of tea will transfer heat
to the air (or to your hand on the mug). The warm room air will transfer its heat to the cold cup
of tea.
Thermal energy is the energy actually being transferred; the transfer of energy is called heat.
3. The Celsius temperature scale is easier to use for Scientists because it is based on increments of
ten where 0° C is freezing and 100° C is boiling. Also, a difference of 100° between these two
critical scientific readings is easier to remember than the 180 degrees between 32° F for freezing
and 212° F for boiling in Fahrenheit.
Chapter 12 Review answers from questions on text book page 341 - 343:
Reviewing Main Ideas (page 341)
(1) Potential and Kinetic Energy are both related to motion. Potential energy is stored energy. It is
acquired through changes in position or condition of matter. Kinetic energy is the energy of
motion; it is released potential energy. The more potential energy something has, the more
kinetic energy something has. Kinetic energy is dependent on both the mass and the speed of
an object.
(2) Temperature measures the average kinetic energy (molecular motion) of all the atoms in a
sample. You measure temperature using a thermometer. Temperature can be measured in
Fahrenheit, Celsius, or Kelvin scales. Scientists normal use Celsius to record temperatures. See
your notes for important temperature readings (freezing, room, body, and boiling).
Chapter 12 Review (pages 342 – 343)
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
Stored energy is potential energy.
Total kinetic and potential energy in the particles of a material is thermal energy.
The type of transfer of thermal energy that produces weather is convection.
The type of transfer of thermal energy from a warmer object to a cooler one is conduction. Heat
is the actual transfer.
The ability to bring about change is energy.
Skip for now (answer is b)
Potential energy is to kinetic energy as (a) water behind a dam is to electrical energy.
Thermometers measure (b) molecular motion.
Gravity changes potential energy to kinetic energy when (b) a skier starts down a slope.
When you place a cooler object against a heat source, you transfer heat by (c) conduction.
Possible examples:
a.
Temperature changes is when tires get hot on a road due to friction or your hands get hot
when you rub them or you get hot when you run
b.
Shape changes when you put your hand in a fist to serve volleyball or you change the
shape of the soccer ball when you kick it
c.
Speed changes when you walk, then jog, then run
d.
Position changes when you lift a bowling ball back before throwing it down the lane
towards the pins
e.
Direction is when you hit a baseball towards left field or you turn around to play defense on
the other end of a basketball court or soccer field
Food provides fuel for your organs and muscles. It changes from chemical energy to thermal
energy and mechanical energy.
Setting up the dominoes gives them potential energy. Tipping over the first one changes that to
kinetic energy. It then transfers its kinetic energy to the next domino down the line.
When you place a cool compress on a burn, it moves the heat from the skin to the cloth
minimizing the damage to the skin
We should put heat vents low and air conditioning vents high because warm, less dense air rises
and cooler, denser air sinks. This helps heat/cool rooms faster.