1. Energy Transformations
Georgia High School Graduation Test:
Science Review

2. Radiation Radiation comes from the nucleus of an atom.
Unstable nucleus emits a particle or energy  alpha
 beta
 gamma

3. Sample Question
Describe the process of radioactive decay in which the unstable nucleus of a radioactive isotope spontaneously decays.

4. Radioactivity
the spontaneous process that occurs when an unstable nucleus releases particles from the nucleus and/or energy to form a more stable nucleus

5. Radioisotopes unstable radioactive nucleus examples: carbon-14
deuterium (hydrogen with 1 neutron)
all elements with atomic numbers above 83

6. Transmutation
The changing of one element to another is called transmutation
This occurs whenever there is an alpha decay or a beta decay
Remember, that for a gamma decay, the nucleus just changes internal energy levels, but doesn’t change the identity of nucleons

7. Radioactive Decay
radioactive decay = the release of subatomic particles by radioactive isotopes
alpha and beta decay result in transformed atom
gamma decay results in same atom with release of energy
ALPHA DECAY
BETA DECAY
GAMMA DECAY

8. Half-Life
The time it takes for half of the radioactive particles in a radioactive nucleus to decay
One-half of that one-half will decay in the next half life
One-half of that one-fourth will decay in the next half life

9. Half-Life

10. Sample Question
Calculate the amount of radioactive substance that will remain after one half-life.

11. Half-life
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

12. Heat and Temperature
In order to understand the nature of heat and temperature, it is necessary to appreciate the fact that matter consists of moving particles (atoms or molecules) which can interact with one another.

13. Heat and Temperature
The motion of the particles is increased by raising the temperature.
The motion of the particles is reduced by lowering the temperature.

14. Sample Question
What is the effect of an increase in temperature on the motion of atoms?
Ans: the motion of the atoms will increase

15. Temperature a measure of the average kinetic energy of molecules
the higher the temperature, the faster the molecules

16. Sample Question
Compare solids, liquids, and gases in terms of shape, volume, and movement of particles.

17. Phases of Matter STATE OF MATTER SHAPE VOLUME PARTICLE DESCRIPTION
SOLID
has definite shape
has definite volume
particles move slowly and cannot be compressed
LIQUID
has no definite shape (takes the shape of container)
particles move faster but cannot be compressed
GAS
has no definite shape
has no definite volume (fills volume of container)
particles move the fastest and can be compressed

18. Phase Changes of Water

19. Phase Change Diagram of Water

20. Sample Question
What is the effect of temperature change on the phases of matter?

21. 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

22. Flow of Heat & Equlibrium
Remember that Energy is Conserved, so if 1 substance loses heat the other gains heat.
Thermal Equilibrium
Heat will flow from a hot object to a cold object until they are at the same temperature.

23. 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

24. Conduction Transfer of heat by direct contact of molecules.
Molecules collide and transfer kinetic energy
Can occur in all 3 states of matter
Occurs the best in solids because they are more dense

25. Conduction Transfers heat until Thermal equilibrium is reached.
Both substances reach the same temperature.

26. Convection
Transfer of heat in fluids (gases & liquids) through currents.
Convection is the movement of gases or liquids from a cooler spot to a warmer spot
The hotter fluid tends to be less dense and therefore rise pushing cooler more dense fluid to the bottom causing what are called convection currents.

27. Ways heat can be transferred
Radiation
Transfer of heat in waves
Does not require matter
Types
Electromagetic radiation (objects give off heat)

28. Sample Question
Give examples and describe the two forms of energy encountered in a system between any of the following: chemical, heat, light, electrical, and mechanical.

29. Types of Energy
Ans:
potential energy = stored energy due to position or chemical composition
kinetic energy = energy due to motion

30. 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.

31. Energy Sources SOURCE DEFINITION EXAMPLES chemical heat light
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 from burning gas
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

32. 7. Question
Describe the different forms of energy transformations when turning on a light switch.
Ans:
Electrical →heat →light

33. 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?

34. Lesson Summarized Write a sentence that explains the system discussed.
Draw a graphic organizer that shows the relationship of the parts to the whole.

35. Figure Reference
Radioactive Decay figures: retrieved from
Phase Changes of Water figure: retrieved from
Phase Change Diagram of Water figure: retrieved from
Conversion of Energy figure: retrieved from