What do all of these things have in common?
They are types of energy Law of conservation of energy
Definitions Energy Kinetic energy Potential energy Law of conservation ofenergy Warm Up #1 What is the energy possessed bymatter due to its motion called? What are the two main types ofenergy? Give unique examples of the two maintypes of energy. Look at your activity from yesterday. Did it follow the law of conservation ofenergy?What is your evidence? Mechanical Energy Definition Kinetic energy how do you increase?
Faster Larger objects (moremass) Potential energy how do you increase? Put more in the bank Mechanical Energy Kinetic Wind Electricity Radiant or Light Potential Chemical Nuclear Thermal Conservation of Energy
Cant create or destroy energy Total is the same Ski hill Energy at the top Energy in the middle Energy at the bottom Changes Energy Forms Happens in all changes Spreads out
Makes thingsmore chaotic Think of yourlocker or room Warm Up #2 Video What are the major types of energy ofthe following before the collision andafter? Balloon Water Person What other types of energy areprobably present? Mechanical Waves Transfers energy through a medium Medium Types
Definition Examples Types Transverse Longitudinal How the matter moves Parts of a Transverse Wave Speed of Waves Speed = frequency x wavelength v = fl
Speed (m/s) Wavelength (m) Frequency (Hertz = Hz = cycles/second) Find the speed of a wave if it has a frequencyof 5 Hz and a wavelength of 12m. A wave is traveling with a speed of 224m/s.What is the frequency of this wave given itswavelength is 37 m? Given the frequency is 110Hz and the speedis 1500 m/s, what is the wavelength? Energy in Waves Which set of hills takes more energy to run?
High energy Short wavelength High frequency Large amplitude Clicker Quiz Warm-Up #3 Take the paper clip and unfold it
Then bend it back and forth over in the same location several times Place the point where you are bending it on your lips What do you observe? What conclusions can you make from your observations and what we have learned in class? Electromagnetic Wave Definition Electromagnetic spectrum
Travel at the speed of light (3x108 m/s) Vary in wavelength and frequency Uses Radio Microwave Infrared Visible Ultraviolet X-ray Gamma
Really Muscular Idiots
Visualize Ultra X-treme Grannies Heat Thermal energy - definition Heat - definition Beaker example
Flows from high temp. to low temp. Beaker example Compare temperature Compare thermal energy How would heat move? (A to B or B to A) Heat = energy transferred between objects that have different temperatures; matter doesnt contain heat, matter contains thermal energy and transfers that energy which is heat Thermal energy will be transferred from the high temp. object to the low temp. object until thermal equilibrium is reached which is when all the objects have the same amount of thermal energy and generally the same temperature In the beakers: the temperatures are equal at 100oC, there is more thermal energy in beaker A because there are more molecules so there is a higher total KE Cold really is the lack of thermal energy; so really we have high or low thermal energy Beaker A 100oC 100 mL Beaker B 100oC 50 mL How is Thermal Energy Transferred?
Conduction Direct contact Collisions Changes High temp. to low temp. Conduction is one way that thermal energy can be transferred it requires the two objects to be touching each other, the faster molecules in one object collide with the slower molecules of the other and transfer KE which causes the slower molecules to speed up (increase temp.) Energy is always transferred from high temp. to low temp. = 2nd law of thermodynamics Conductors substances that transfer energy well, metals are good conductors Insulators substance that are poor at transferring energy; fiberglass, water, paper are good insulators and poor conductors Convection Movement in liquid or gas Hot liquids
Less dense Rise Collides with slower, cooler liquid More dense Sinks Reheated near source Process repeats Currents Oceans Atmosphere Convection: transfer of thermal energy through motion of a gas or liquid As a liquid is heated it becomes less dense as the molecules speed up and spread out and less dense things will rise As the warmer liquid rises it collides with cooler and slower moving molecules and transfers energy to those molecules making the original molecules to lose energy and become a cooler temperature and more dense and thus sink As the liquid/gas gets near the heat source, the process begins again This creates currents of upward and downward moving water/air This happens in the ocean and the atmosphere (creates thermals that you see birds soaring on but staying in about the same place) Radiation Definition Examples Car on cold day T-shirt on sunny day
Greenhouse effect Heat transfer by light waves (electromagnetic radiation, so more than just visible light) Car on cold day or t-shirt on a sunny day can get really warm depending on the color even warmer than the air surrounding it This occurs greenhouse effect where light enters the atmosphere and is absorbed by objects which increases the temperature of the object and then heat is transferred to the atmosphere and can be held in by the gases (carbon dioxide, methane and water vapor) in the atmosphere