EnergyEnergy is the ability to do work is the ability to do work!!

WorkWork is simply a means of transferring energy. is simply a means of transferring energy. The work done when an archer draws her bow, gives the The work done when an archer draws her bow, gives the

bow the ability to do that amount of work on the arrow.bow the ability to do that amount of work on the arrow. When work is done to raise a hammer, the hammer When work is done to raise a hammer, the hammer

acquires the ability to do that work on the object it hits acquires the ability to do that work on the object it hits when it falls.when it falls.

Energy is measured in Energy is measured in JoulesJoules (just like work). (just like work). 1 Calorie (like in food) is equal to 4186 Joules1 Calorie (like in food) is equal to 4186 Joules

EnergyEnergy

Remember the work/power activity you did last Remember the work/power activity you did last semester? If you know your weight in lbs, times semester? If you know your weight in lbs, times 2.2 to get your force in Newtons, you can find 2.2 to get your force in Newtons, you can find the Work you do….the Work you do…. Work = force x distanceWork = force x distance Divide that by 4186 Joules and you will have the Divide that by 4186 Joules and you will have the

number of Calories that you would need to consume number of Calories that you would need to consume to accomplish that particular activity. to accomplish that particular activity.

To find the amount of Cal needed for a 135 lb girl to To find the amount of Cal needed for a 135 lb girl to walk up 20 meters of stairs:walk up 20 meters of stairs:

135lb x 2.2 = 297N 135lb x 2.2 = 297N

Work = 297N x 20m = 5940J / 4186J = 1.42 CWork = 297N x 20m = 5940J / 4186J = 1.42 C

Types of EnergyTypes of Energy

Mechanical EnergyMechanical Energy Potential Energy (PE)Potential Energy (PE)

Gravitational PEGravitational PEElastic PEElastic PE

Kinetic Energy (KE)Kinetic Energy (KE)Thermal EnergyThermal EnergyChemical EnergyChemical EnergyElectrical EnergyElectrical EnergyElectromagnetic EnergyElectromagnetic EnergyNuclear EnergyNuclear Energy

Define each of the 10 terms.

Draw picture examples of each.

Include the formulas for GPE and KE.

Formula: Formula: GPE = weight x heightGPE = weight x height or or mghmgh

What is its gravitational PE of a 10kg boulder sitting What is its gravitational PE of a 10kg boulder sitting on a desk 1 meter above the ground?on a desk 1 meter above the ground?

PE = mghPE = mgh; ;

= 10kg x 9.8m/s= 10kg x 9.8m/s22 x 1m x 1m

= = 98Nm or 98J98Nm or 98J

Gravitational Potential EnergyGravitational Potential Energy

Height is Height is VERTICAL VERTICAL height, not horizontal distance height, not horizontal distance traveled to get from point a to point btraveled to get from point a to point b

Gravitational Potential EnergyGravitational Potential Energy

2 m 2 m2 m

KE = ½ m vKE = ½ m v22

If you double the mass, what happens to the KE?If you double the mass, what happens to the KE? If you double the speed, what happens to the KE?If you double the speed, what happens to the KE? If you triple the speed, what happens to the KE?If you triple the speed, what happens to the KE? Which has the greater impact on KE, changing the Which has the greater impact on KE, changing the

mass or changing the speed?mass or changing the speed?

When the brakes of a motorcycle traveling at 60 When the brakes of a motorcycle traveling at 60 km/h lock, how much farther will it skid than if he km/h lock, how much farther will it skid than if he had been traveling at 20 km/h?had been traveling at 20 km/h?

Mechanical Energy: KineticMechanical Energy: Kinetic

Mechanical Energy: KineticMechanical Energy: Kinetic

30 km/h

60 km/h

120 km/h

10 m skid

40 m skid

160 m skid

Law of Conservation of EnergyLaw of Conservation of Energy: Energy : Energy cannot be created or destroyed; it may be cannot be created or destroyed; it may be transformed from one form to another, but the transformed from one form to another, but the total amount of energy never changestotal amount of energy never changes. .

o Ex: PendulumEx: Pendulum

Conservation of EnergyConservation of Energy

PE = 10J

PE = 4J

KE = ?

PE = ?

KE = ?

PE = 7J

KE = ?

PE = 10J

KE = ?

Why is the 2nd hill of a rollercoaster always shorter than the first?

C:\Users\Phillips\Dropbox\School Files\C:\Users\Phillips\Dropbox\School Files\Curriculum\4-Physics\Work and Energy\PE-KE Curriculum\4-Physics\Work and Energy\PE-KE Demo.mhtDemo.mht

Nearly every process in nature can be understood as a Nearly every process in nature can be understood as a transformation of energy from one form to another.transformation of energy from one form to another.

SingshotSingshot

There is no net loss or gain when energy There is no net loss or gain when energy transforms states!transforms states!

Ultimate source of energy in the universe is the Ultimate source of energy in the universe is the sunsun.. Trace the energy from the sun through conversions to the Trace the energy from the sun through conversions to the

energy of a basketball as it falls through the hoop.energy of a basketball as it falls through the hoop. Trace the energy from the sun through conversions to a Trace the energy from the sun through conversions to a

powerplant converting water at a dam to electricity.powerplant converting water at a dam to electricity.

Conservation of EnergyConservation of Energy

Energy and MassEnergy and Mass

Einstein’s equation, E = mcEinstein’s equation, E = mc22 revolutionized the revolutionized the science world and pointed to a previously science world and pointed to a previously untapped area of power. untapped area of power. Energy and Mass can be converted into each other.Energy and Mass can be converted into each other. c = speed of light which is 3 x 10c = speed of light which is 3 x 1088 m/s m/s A very small amount of mass can be converted into A very small amount of mass can be converted into

enormous amounts of energy.enormous amounts of energy.1g = 9 x 101g = 9 x 101616 J of energy J of energy

1 g of TNT = 2931 J1 g of TNT = 2931 J Ex: Nuclear energy….Atomic BombEx: Nuclear energy….Atomic Bomb

Energy ResourcesEnergy ResourcesNonrenewable Energy ResourcesNonrenewable Energy Resources exist in limited exist in limited amounts and cannot be replaced except over the amounts and cannot be replaced except over the course of millions of years.course of millions of years. UraniumUranium Fossil fuelsFossil fuels – ____________________ – ____________________

The majority of fuels used today in the world are fossil fuels.The majority of fuels used today in the world are fossil fuels. Pro: Relatively inexpensive and generally easy to obtain.Pro: Relatively inexpensive and generally easy to obtain. Con: They are not evenly distributed, resulting in large scale political Con: They are not evenly distributed, resulting in large scale political

maneuverings to control the sources.maneuverings to control the sources. Con: Large amounts of pollution.Con: Large amounts of pollution. Con: The only way to extend the use of the fossil fuels and other Con: The only way to extend the use of the fossil fuels and other

sources that are gone for good once used, is to sources that are gone for good once used, is to conserveconserve – reducing – reducing energy needs and increasing the efficiency of energy use.energy needs and increasing the efficiency of energy use.

All energy resources have pros and cons.All energy resources have pros and cons.

http://io9.com/swedish-researchers-create-an-http://io9.com/swedish-researchers-create-an-impossible-material-by-880572412impossible-material-by-880572412

http://youtu.be/SBWi3NtND68

http://www.sustainablebusiness.com/index.cfm/go/news.display/id/24305

Stanford researchers find electrical current stemming from plants Stanford researchers find electrical current stemming from plants Stanford engineers have generated electrical current by tapping Stanford engineers have generated electrical current by tapping into the electron activity in individual algae cells. into the electron activity in individual algae cells.

Photosynthesis excites electrons, which can then be turned into an Photosynthesis excites electrons, which can then be turned into an electrical current using a specially designed gold electrode. This electrical current using a specially designed gold electrode. This studystudy could be the first step toward carbon-free electricity could be the first step toward carbon-free electricity directly from plants.directly from plants.

The result, the researchers say, is electricity production that The result, the researchers say, is electricity production that doesn't release carbon into the atmosphere. The only byproducts of doesn't release carbon into the atmosphere. The only byproducts of photosynthesis are protons and oxygen.photosynthesis are protons and oxygen.

"This is potentially one of the cleanest energy sources for energy "This is potentially one of the cleanest energy sources for energy generation," Ryu said. "But the question is, is it economically generation," Ryu said. "But the question is, is it economically feasible?“ …they would need a trillion cells photosynthesizing feasible?“ …they would need a trillion cells photosynthesizing for one hour just to equal the amount of energy stored in a AA for one hour just to equal the amount of energy stored in a AA battery. In addition, the cells die after an hour. battery. In addition, the cells die after an hour.

Harvesting electrons this way would be more efficient than burning Harvesting electrons this way would be more efficient than burning biofuels, as most plants that are burned for fuel ultimately store biofuels, as most plants that are burned for fuel ultimately store only about 3 to 6 percent of available solar energy, Ryu said. only about 3 to 6 percent of available solar energy, Ryu said. Electron harvesting in this study was about 20 percent efficient. Electron harvesting in this study was about 20 percent efficient. Ryu said it could theoretically reach 100 percent efficiency one Ryu said it could theoretically reach 100 percent efficiency one day. (day. (Photovoltaic solarPhotovoltaic solar cells are currently about 20 to 40 cells are currently about 20 to 40 percent efficient.)percent efficient.)

Possible next steps would be to use a plant with larger Possible next steps would be to use a plant with larger chloroplasts for a larger collecting area, and a bigger electrode chloroplasts for a larger collecting area, and a bigger electrode that could capture more electrons. With a longer-lived plant and that could capture more electrons. With a longer-lived plant and better collecting ability, they could scale up the process, Ryu better collecting ability, they could scale up the process, Ryu said. Ryu is now a professor at Yonsei University in Seoul, South said. Ryu is now a professor at Yonsei University in Seoul, South Korea.Korea.

http://www.whydontyoutrythis.com/2013/02/Stanford-researchers-find-electrical-current-stemming-from-plants.html?m=1

Gwyneth Dickey is an intern at the Stanford News Service

What kid doesn’t like kicking around a soccer ball? Imagine if this What kid doesn’t like kicking around a soccer ball? Imagine if this fun activity could also provide enough energy to power fun activity could also provide enough energy to power something useful in a modest off-grid African village, like a something useful in a modest off-grid African village, like a reliable light to cook by or an emergency mobile phone. The reliable light to cook by or an emergency mobile phone. The sOccket is a prototype soccer ball that captures kinetic energy sOccket is a prototype soccer ball that captures kinetic energy when it is kicked or thrown, stores it in an internal battery and when it is kicked or thrown, stores it in an internal battery and makes that energy available for a myriad of small but useful makes that energy available for a myriad of small but useful purposes. In other words, it’s a fun, portable energy-harvesting purposes. In other words, it’s a fun, portable energy-harvesting power source that is designed to take a kicking.power source that is designed to take a kicking.

The sOccket team says it hopes the invention will help prevent The sOccket team says it hopes the invention will help prevent house fires caused by kerosene lamps relied on for lighting by house fires caused by kerosene lamps relied on for lighting by more than 1 billion people worldwide. They report that kerosene more than 1 billion people worldwide. They report that kerosene is not only expensive in many areas but also highly flammable is not only expensive in many areas but also highly flammable and the smoke has been known to cause respiratory problems in and the smoke has been known to cause respiratory problems in infants and adults. infants and adults.

The four-girl sOccket team began as one of many groups in an The four-girl sOccket team began as one of many groups in an engineering sciences class at Harvard University. engineering sciences class at Harvard University.

Recently it seems like there has been a rash of renewable energy ideas for Recently it seems like there has been a rash of renewable energy ideas for charging our gadgets, especially our cell phones, but this latest technology is charging our gadgets, especially our cell phones, but this latest technology is probably my favorite. A team of researchers at UT Arlington have developed probably my favorite. A team of researchers at UT Arlington have developed micro-windmills only one-tenth the size of a grain of rice that could one day be micro-windmills only one-tenth the size of a grain of rice that could one day be used to charge cell phones. Hundreds of the 1.8 mm-wide devices could be used to charge cell phones. Hundreds of the 1.8 mm-wide devices could be embedded in a sleeve for a cell phone and then wind, whether by waving the embedded in a sleeve for a cell phone and then wind, whether by waving the phone in the air or by holding it up on a windy day, would generate electricity phone in the air or by holding it up on a windy day, would generate electricity and charge the battery. The devices are made out of durable nickel alloy that in and charge the battery. The devices are made out of durable nickel alloy that in testing withstood high artificial winds without any fracture in the material. They testing withstood high artificial winds without any fracture in the material. They can be made in a batch process where hundreds or thousands can be made on can be made in a batch process where hundreds or thousands can be made on a single wafer, which would make them inexpensive to produce. a single wafer, which would make them inexpensive to produce.

Beyond charging our gadgets, the researchers think that the micro-windmills could also be applied to flat panels mounted on the walls of houses or buildings to harvest energy for lighting, security or environmental sensing and wireless communication. The researchers are already partnering with WinMEMS Technologies Co., a Taiwanese fabrication company, to produce the devices.

Micro-windmills could one day charge cell phonesMegan TreacyJan 13, 2014http://www.treehugger.com/clean-technology/micro-windmills-could-one-day-charge-cell-phones.html#mkcpgn=fbsci1

http://thinkprogress.org/climate/2014/02/04/3241811/http://thinkprogress.org/climate/2014/02/04/3241811/iceland-geothermal-magma-energy/iceland-geothermal-magma-energy/

Renewable Energy ResourcesRenewable Energy ResourcesRenewable resourcesRenewable resources can be replaced in a relatively can be replaced in a relatively short period of time…..most originate directly or short period of time…..most originate directly or indirectly from the sun.indirectly from the sun.

http://youtu.be/SBWi3NtND68http://youtu.be/SBWi3NtND68 Hydroelectric EnergyHydroelectric Energy Passive Solar EnergyPassive Solar Energy Active Solar Energy SystemsActive Solar Energy Systems Geothermal EnergyGeothermal Energy Biomass EnergyBiomass Energy Hydrogen Fuel CellsHydrogen Fuel Cells Wind EnergyWind Energy Tidal EnergyTidal Energy

Define each of the 9 terms

Give one pro and one con for their use

Draw a picture representing each