Transcript Energy Transformations Lesson

Energy
Transformations
Georgia High School
Graduation Test:
Science Review
Mrs. Kirby
Introduction
• From the key vocabulary,
circle the words that you
can already define or use in
a sentence.
• Write down two or three
things that you think are
important for you to know
today.
Sample Question
1.Describe the process
of radioactive decay
in which the unstable
nucleus of a
radioactive isotope
spontaneously
decays.
Radioactivity
• the spontaneous process
that occurs when an
unstable nucleus
releases particles and/or
energy to form a more
stable nucleus
Radioisotopes
• unstable radioactive nucleus
• examples:
• carbon-14
• deuterium (hydrogen with
1 neutron)
• all elements with atomic
numbers above 83
Radioactive Decay
•radioactive decay = the release
of subatomic particles by
radioactive isotopes
ALPHA DECAY
•alpha and beta decay result in
transformed atom
•gamma decay results in same
atom with release of energy
BETA DECAY
GAMMA DECAY
Sample Question
2.Calculate the amount
of radioactive
substance that will
remain after one halflife.
Half-life
• the time it takes for half of the
radioactive particles in a radioactive
nucleus to decay
• example:
• If an original sample of carbon-14
has a mass of 10 grams and its
half-life is 5700 years, how many
grams of carbon-14 would remain
after one half-life?
• ANSWER: 5 grams
Sample Question
3.What is the effect of
an increase in
temperature on the
motion of atoms?
Temperature
•a measure of the
average kinetic
energy of molecules
•the higher the
temperature, the
faster the molecules
Sample Question
4.Compare solids,
liquids, and gases in
terms of shape,
volume, and
movement of
particles.
Phases of Matter
STATE OF
MATTER
SHAPE
VOLUME
PARTICLE
DESCRIPTION
has definite
volume
particles move
slowly and
cannot be
compressed
SOLID
has definite
shape
LIQUID
has no definite
shape (takes
the shape of
container)
has definite
volume
particles move
faster but
cannot be
compressed
has no definite
shape
has no definite
volume (fills
volume of
container)
particles move
the fastest and
can be
compressed
GAS
Sample Question
5.What is the effect of
temperature change
on the phases of
matter?
Phase Changes
• to increase the temperature
of a substance energy must
be absorbed by that
substance
• to decrease the temperature
of a substance energy must
be released by that
substance
Phase Changes of Water
Phase Change Diagram
of Water
Sample Question
6. Give examples and
describe the two forms
of energy encountered
in a system between any
of the following:
chemical, heat, light,
electrical, and
mechanical.
Types of Energy
• potential energy = stored
energy due to position or
chemical composition
• kinetic energy = energy due to
motion
Energy Sources
SOURCE
DEFINITION
EXAMPLES
chemical
energy stored in chemical
bonds, food, or fuel
cause of burning
gas, energy from
food
heat
total amount of energy of
atoms of matter
boiling water, heat
light
energy that travels in
waves and moves through
empty space
any electromagnetic
wave (radio, visible,
UV, x-rays, gamma)
electrical
energy due to the motion
of charges
current electricity
mechanical
energy acquired or
released by moving
objects
falling rock,
swinging a baseball
bat, sound
from burning gas
Heat Energy
• Heat can be transferred through:
• Conduction = when objects touch
• Convection = when matter moves
• Radiation = in the form of waves (does
not require matter)
• Conductors = easily transmit energy
• Example: metals
• Insulators = do not easily transmit
energy
• Example: gases such as air
Conversion of Energy
• The sum of KE and PE is constant if there is
no friction.
• Realistically, some energy is transferred to
heat due to the friction between the wheels
and the track.
Discussion
• The molecular theory of molecules
states that the velocity of molecules
correlates to the temperature of the
system. How are the actions of a
group of people affected by the
temperature of a room? How are
those actions similar to and different
from atoms at the same
temperature?
Lesson Summarized
• Write a sentence that
explains the system
discussed.
• Draw a graphic organizer
that shows the relationship
of the parts to the whole.
Short Quiz Answers
1. Half-time is the time it takes for half
of the radioactive particles in a
radioactive nucleus to decay.
2. All isotopes have the same atomic
number but different atomic masses.
3. Some isotopes are radioactive due to
the different number of neutrons.
4. See the table on sources of energy.
5. Ice, water, and steam all have the
same chemical composition (H2O) but
each are in a different phase.
More Practice
• From the blue book, complete
the following questions:
•
•
•
•
•
p.53 (26,27,30)
p.61 (1-4)
p.62-63 (6-8)
p.64 (11-14)
p.68 (21-25)