Download Matter and Energy

Matter and Energy (pp. 71 – 76)
Definitions
Section 3.1
Energy The ability to do work or cause a change
Kinetic Energy The energy of motion.
Potential energy Stored Energy
SHORT ANSWER – use complete sentences
How can you tell kinetic energy and potential energy apart?
Kinetic energy is present only if an object is moving. Potential energy is due to chemical
composition or position but not motion.
How can a skater that has less mass have more kinetic energy than a skater that has more mass?
Kinetic energy increases as mass increases and also as speed increases. If the skater with less
mass was going at a high speed and the skater with more mass was going really slowly then the
skater with less mass could have more kinetic energy.
Name two things you can do to increase an objects potential energy.
1. Add mass
2. Lift the object further away from earth.
Matter and Energy (pp. 71 – 76)
Section 3.1
Match each description with the correct form of energy. Answers are used more than once
1. ______C_____ gasoline burns producing heat
A. mechanical
2. ______F_______ this energy keeps the sun burning
B. sound
3. ______E_______ the sun releases large amounts of this energy
C. chemical
4. ______B______ this energy cannot travel through empty space
D. thermal
5. _______A_______ a heavy backpack is picked up off of the floor
E. electromagnetic
6. _______E_______ X-rays taken at the doctors office use this energy
F. nuclear
7. _______D______ the total energy of all the moving molecules and atoms inside an object
8. _______C______ digesting food provides body cells with energy
9. ________A______ kicking a soccer ball causes it to fly across the field
10._______D______ water in a pot is very hot, it’s molecules have lots of this kind of energy
11._______B______ a boy hits a drum causing the air to vibrate. What kind of energy is the vibration?
12._______F______ the source for this energy is in the nucleus of the atom
13. _______B______ a girl whispers in your ear causing your ear drum to vibrate
14.________D_____ ice cubes are very cold, they have very little of this kind of energy
Kinetic energy __________increases_________________ as mass increases.
Kinetic energy __________ increases ___________________ as speed increases.
Matter and Energy (pp. 77 – 83)
Section 3.2
Definitions
Law of conservation of energy
The law that states energy can never be created or destroyed.
Energy efficiency Measurement of usable energy after a conversion.
Label the Diagram
Label the illustration with the following six phrases:
Most potential energy
Most Kinetic Energy
Kinetic Energy is Increasing
Least potential energy
Least Kinetic Energy
Potential Energy is Increasing
Least Kinetic Most Potential
Energy
Energy
Kinetic Energy is
Increasing
Potential Energy is
Increasing
Most Kinetic
Energy
Least Potential
Energy
Matter and Energy (pp. 77 – 83)
Section 3.2
The book describes all the energy conversions that must take place in order to light a match. List
all five of these energy conversions.
1. Plants convert electromagnetic energy to chemical energy (photosynthesis)
2. People eat the plants and the chemical energy is used to move the match. This means that
chemical energy is converted to kinetic energy.
3. The motion of the match against the surface is kinetic energy and this energy is converted to
heat energy.
4. The heat energy starts a reaction in the head of the match and is converted to chemical energy.
5. The match burning is chemical energy and that energy is converted to thermal energy (heat)
and electromagnetic energy (light).
Describe an energy conversion that you have observed in your own life.
Answers vary
Give an example of an energy conversion that produces unwanted forms of energy. List the
wanted forms of energy that are produced and also list the unwanted forms of energy.
Energy Conversion: Answers Vary
Wanted forms of energy:
Unwanted forms of energy:
Matter and Energy (pp. 86 – 90)
Section 3.3
Definitions
Solar cell
Short Answer – use complete sentences
How are LEDs more efficient than incandescent lights?
LEDs convert almost all of the electrical energy they use into light. Incandescent light bulbs
produce unwanted heat; therefore they are not as efficient.
Give an example of a common technology that does not efficiently convert energy. What forms of
unwanted energy are produced?
Burning of gasoline in cars is not efficient. A lot of the chemical energy is wasted as heat and
sound.
List two advantages and two disadvantages of solar power
Advantages
Disadvantages
1. Quiet and Clean
1. Inefficient
2. Renewable
2. Expensive
Satellites orbiting the earth use solar cells to produce energy. Why are solar cells the ideal choice?
Satellites are hard to reach so any form of chemical energy would be difficult to replace. The sun
does not require replacing!
Matter and Energy (pp. 71 – 90)
Chapter 3 Review
All forms of energy are a combination of (d) potential energy and kinetic energy
a.
b.
c.
d.
mechanical energy and chemical energy
chemical energy and kinetic energy
potential energy and thermal energy
potential energy and kinetic energy
Which type of energy is transmitted by vibrations of air? (b) sound
a.
b.
c.
d.
Electromagnetic
Sound
Nuclear
Chemical
When energy is converted from one form to another, what is usually produced? (c) heat
a.
b.
c.
d.
chemical energy
gravity
heat
nuclear energy
An objects kinetic energy id determined by its (c) mass and speed
a.
b.
c.
d.
position and composition
speed and position
mass and speed
height and width
Which of the following is a conversion from chemical energy to mechanical energy?
(d) a person lifting a weight
a.
b.
c.
d.
a dark light bulb starting to glow
food being heated in an oven
a ball rolling down a hill
a person lifting a weight
Matter and Energy (pp. 71 – 90)
Chapter 3 Review
An energy-efficient electric fan converts a large portion of the electrical energy that enters it into
(b) kinetic energy of the fan blades
a.
b.
c.
d.
an unwanted form of energy
kinetic energy of the fan blades
thermal energy in the fan’s motor
sound energy in the fan’s motor
the energy in wind used to generate electricity is (d) kinetic energy
a.
b.
c.
d.
chemical energy
sound energy
potential energy
kinetic energy
a skier on a hill has potential energy due to (d) position
a.
b.
c.
d.
speed
energy efficiency
compression
position
One air conditioner becomes hot to the touch when it is in use. Another air conditioner stays cool
to the touch when it is in use. Which air conditioner is the most energy efficient? How do you
know?
The heat produced is unwanted energy. The air conditioner that stays cool to the touch is more
efficient because it produces less unwanted energy.
Matter and Energy (pp. 71 – 90)
Chapter 3 Review
Look at the “Thinking Critically” Illustration on page 94
At what two points in the illustrations would the skater have the most potential energy?
1 and 5
At what point in the illustration would the skater have the most kinetic energy?
4 (I will also accept 3)
At what point in illustration B will the skater’s kinetic energy begin to be changed by to potential
energy?
2
What unwanted forms of energy might be produced in this energy conversion?
Heat and sound