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 ALPHA DECAY BETA DECAYGAMMA 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

Sample Question 2.Calculate the amount of radioactive substance that will remain after one half- life.

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 SHAPEVOLUME 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) has definite volume 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

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 SOURCEDEFINITIONEXAMPLES 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 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

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.table 5.Ice, water, and steam all have the same chemical composition (H 2 O) but each are in a different phase.phase

More Practice From the blue book, complete the following questions: p.53 (26,27,30) p.61 (1-4) p (6-8) p.64 (11-14) p.68 (21-25)