1. Describe the energy transfers that occur in a light bulb.2. Describe the energy transfers that occur when the body is powered by food.
Wt=50N 1. What is the KE at point A? Why? 2. What is the PE at point A? 3. What is the ME at point A? 4. What is the PE at point C? 5. What is the KE at point C?
Energy Types Copy this chart in your notes with enough room to add details. Use your book to fill in the information. Type Descriptions/Explanations Examples Mechanical Thermal Chemical Electrical Sound Light Nuclear
1. Describe the energy transfers in a hairdryer. 2. What is the difference between renewable and nonrenewable energy resources?
Forms Explanation Example Total energy ofMechanical motion and position Total kinetic energyThermal of particles Energy stored inChemical rearranging atoms
Energy of movingElectrical electrons Energy of vibratingSound particles Vibrations of electricallyLight charged particles Energy in the nucleus ofNuclear an atom
1. Mechanical Energytotal energy of motion and positionME=KE + PE
An object on the top of a hill has high ____ energy and low ____ energy.As the object rolls down, what happens?Why does there seem to be less energy at the bottom of the hill than at the top?
2. Electrical Energythe energy of moving electrons Like charges repel and + + Opposite charges attract + -
Two Types of ElectricityStatic ElectricityCurrent Electricity
The Power of Electricity Can be turned into other kinds of energy Can do work Hairdryer converts electric to thermal Alarm clock converts electric to sound and light
3. Nuclear Energy the energy of the nucleus of an atom Fission Fusion
Pros and Cons of Nuclear Energy Fission Fusion + make electrical + fuel is plentiful energy + only small amounts + no carbon dioxide or of radioactive waste other gases products - limited fuel supply - not currently - radioactive waste practical products - large amount of - possible release of energy needed to radioactive material heat and contain the hydrogen plasma
The SunGiant nuclear fusionreactorUltimate source ofenergy for our planet
4. Chemical Energy the energy of rearranging atoms Is photosynthesis endothermic or exothermic? Is respiration endothermic or exothermic?
5. Sound Energythe energy of vibrating particles-caused by vibrations & carried through a substance.
Making Sound vs. Hearing Sound Have you heard this riddle? If a tree falls in the forest and no one is around to hear it, does the tree make a sound? 0 What do you think?
When a tree falls and hits the ground, the tree and the ground vibrate. These vibrations are transferred to the surrounding air. 0 So there would be a sound!!!
Change Frequency = Change Pitch TRY IT! – Vocal cords WATCH IT! – Jars vs. Bottles
TRY IT! Hold the cut rubber band stretched tight. Have a partner pluck the rubber band with their finger. Notice the pitch. Shorten the length of rubber band by holding it in the middle. What was different??
6. Light Energythe vibrations of electrically charged particles Called PHOTONS
The EM Spectrum Visible light is one portion of the Electromagnetic Spectrum. All of these waves are energy- filled waves. Insects, like bees, see shorter wavelengths than humans. What type of EM waves do they see? WATCH IT! - prism
Possibilities of Light Light rays move away from their source in straight lines. When they hit something, they are either Absorbed Reflected Refracted (stopped) (bounced off) (bent) WATCH IT! - Mirror
TRY IT! Fill beaker half full of water. Put a pencil in the glass. Look at the pencil through the side of the glass. How does the pencil look different than it did before you put it in the water? This is an example of ______________.
TRY IT! Prop up the card with the arrow on it. Place a glass of water a little to one side of the card and a few inches in front of it. Now stoop down until your eyes are level with arrow. Slide the glass between the card and your eyes. Try sliding it back and forth a few times. What happened? What causes this?
Light Source or Not? You can see a light source even in the dark because its light passes directly into your eyes. Most things around you are not light sources. Why can you still see them? You can still see them because light from light sources reflects off the objects and then travels to your eyes.
The Speed of Light Watch this clip to learn more about the speed of light.
Check your Light UnderstandingWhat is a photon?On the EM spectrum, what type of EM radiation has the highest energy – radio waves, gamma rays, or x-rays?What are 3 possible things that can happen to light rays after they leave the source?
Sound & Light: Alike, but Different Sound Light *vibration *does NOT *needs a medium need a medium *longitudinal *transverse
7. Thermal Energythe total kinetic energy of the particles more thermal energy = faster moving particles less thermal energy = slower moving particles
Thermal Energy vs. Heat Heat is the transfer of energy between objects that are at different temperatures.
Three Kinds of Heat Conduction Convection Radiation (touch) (current) (rays) Hot Cold Common
Check your Thermal Understanding Is thermal energy kinetic or potential? If you touch something in which the particles are moving faster than the particles in your skin, how would it feel? When objects have more thermal energy than their surroundings, what do you predict will happen in terms of heat?
1. What is heat?2. How does thermal energy play a role in the Law of Conservation of Energy?
Bill Nye; Heat BEFORE: List the forms of energy that you know and understand DURING: Write notes about heat, conduction, convection, radiation AFTER: Write a paragraph that describes thermal energy, heat, and the processes of conduction, convection, and radiation.
Roller Coaster Energy Problems HT=250 m WT=200N HT=20 m WT=200N M=20kg V=200m/s1. Find the PE at point A.2. Find the KE at point A. Answer the3. Find the ME at point A. problems on4. Find the KE at point B. the left on your sheet under the5. What is the ME at point C? roller coaster6. Find the PE at point C. picture.7. Find the KE at point C.