ENERGY Energy – is the ability to do work or cause change

Energy About To Move Potential energy is energy about to happen at any time (it’s stored) Example: ramp ball about to roll- Potential

2 Types of Potential Energy 1.Elastic Potential Energy  Dealing with objects that can be stretched or compressed

2. Gravitational Potential Energy  Gravitational Potential Energy = Mass x Height  Energy is measured in Joules (J)

Test Your Knowledge Which object has the greatest potential energy? 1.An object with a mass of 23 lbs dropped from a height of 30 feet 2.An object with a mass of 5 lbs dropped from a height of 200 feet

Energy Moving Kinetic Energy- is energy in motion- it’s happening now!

Kinetic Energy  Kinetic Energy depends on the mass of an object and its velocity  Kinetic energy = mass velocity²  Energy is measured in Joules (J) *The bigger the object and faster it’s going, the more kinetic energy it produces

Test Your Knowledge Which object has the greatest kinetic energy? 1.An object that has a mass of 100 lbs and a velocity of 3 mph 2.An object with a mass of 50 lbs and a velocity of 6 mph

Potential & Kinetic Energy

Different Forms of Energy

Potential and Kinetic energy come in many different forms Potential and Kinetic energy come in many different forms 1. Electrical Energy Produced from the movement of electrons from Produced from the movement of electrons from one place to another- ELECTRICITY one place to another- ELECTRICITY

2. Electromagnetic Energy  Energy that travels as waves Examples: visible light ultraviolet radiation microwaves radio waves gamma waves

3. Mechanical Energy  Energy produced by the motion or position of an object Examples: *a frog jumping *a car driving *wind mills

4. Thermal Energy  Energy produced when particles move in an object  When particles move around, heat is produced Examples: 1.stoves 2.toasters 3.lit matches 4.rubbing your hands together- friction

5. Chemical Energy  energy produced by chemical reactions  chemical energy is stored (potential) Examples: in food batteries human cells an unlit match

6. Geothermal Energy  energy produced using heat below the earth’s surface Geyser- super heated steam escaping from below the earth’s surface

Geothermal Energy Plant

7. Hydroelectric --(hydropower)  energy produced by flowing water (hydro)  water turns a generator, which then produces electricity Hoover Dam in Nevada

8.Solar Energy  energy produced from sunlight ( a star) What’s an advantage? Disadvantage? How does it work? The sun’s light or photons reach solar panels on earth The photons are then converted into electricity

Solar Panels

9. Nuclear Energy  energy produced by splitting or fusing atoms  energy comes from nucleus of Uranium-235 This is how much energy that is produced from splitting Uranium-235 atoms

Nuclear Fission - Atom Splitting  We use neutrons to split Uranium 235

Review Questions Answer the questions below in the class work section of your notebook 1.Are energy and work the same thing? 2. How are kinetic and potential energy different? 3.Which form of energy do you think is used most often? Explain your answer.

Create A Lab Activity You will be divided into groups of 3 In your group, you and your group members will create a lab to prove that if you add mass and/or velocity to an object you will increases that objects kinetic energy Criteria for Lab: you must use the scientific method to perform the experiment you must supply your own materials (use stuff already around the house) consider how you’re going to test your hypothesis. Consider your variables Each person will turn in their own lab report Those who do not participate in the group will have an alternate assignment Good luck! This will be an M.Y.P assessment

ENERGY TRANSFER AND CONVERSION

LAW of Conservation of Energy Energy cannot be created or destroyed Energy cannot be created or destroyed

Energy can be transferred (sent) from one object to another Energy can be transferred (sent) from one object to another Energy Transfer Example 1: Kicking a ball- From foot to the ball Example 2: Energy from bowling ball to pins

Energy can convert itself from potential to kinetic at any time Energy can convert itself from potential to kinetic at any timeExample: *Hold a ball up high-- Potential *Drop the ball– Kinetic  Can it happen the other way around too? Energy Conversion

Energy conversion in an earthquake Potential energy builds up in earth’s tectonic plates. When that energy is released (kinetic) the result is an earthquake

Energy conversion in a pendulum Energy converts back and forth between potential and kinetic

Deceiving? Look at the famous drawing by M.C. Escher on pg. 480 in your textbook and answer the question below. Where does the water have maximum potential energy?

Energy Conversion from one form to another

Converting from chemical to electrical to sound Battery

Converting from Hydro to mechanical to electrical generator water electricity

Question Can you think of different ways energy is converted from one form to another? Can you think of different ways energy is converted from one form to another?

Energy Conservation If you set a pendulum in motion will it remain in motion forever? If you set a pendulum in motion will it remain in motion forever? Is energy destroyed over time? Is energy destroyed over time?

Law of Conservation of Energy Energy cannot be created or destroyed 1. What happens to the energy in the pendulum then? 2. If it cannot be destroyed then where does it go?

Energy and Friction The pendulum moves through the air The pendulum moves through the air Friction slows the pendulum Friction slows the pendulum Friction increases air molecules movement around the pendulum Friction increases air molecules movement around the pendulum Moving molecules heat up Moving molecules heat up Thermal energy increases Thermal energy increases Mechanical energy converts to thermal Mechanical energy converts to thermal No energy is destroyed No energy is destroyed

Albert Einstein said that sometimes energy can be created by destroying matter E=MC² Albert Einstein said that sometimes energy can be created by destroying matter E=MC² Energy and Matter How can this happen? We can destroy Uranium-235 atoms (matter) This creates huge amounts of energy This discovery means that in some situations energy is not conserved

Review Answer the questions below in the class work section of your notebook. 1.What is energy conservation? 2.State the law of conservation of energy in your own words. 3.Describe the energy conservation that occurs when a ball is dropped and bounces back up. Why does the ball bounce a little lower each time?

 Energy is all around us, and always has been since the beginning of time  What’s different today? We have learned to control energy and that has made our lives easier  But, “with great power comes great responsibility”– Can the human race handle it?  Or, will it handle us? Final Thoughts