## Energy

## Objective 1.1:

**Describe that energy is ability to cause change qualitatively.**

KE = ½ m v^2

PE = mgh

**Summary of Concept:**Any object that has the ability to cause change can do so because it has energy. There are many different forms of Energy and all of them have one thing in common... they can all cause change.

When dealing with objects in motion we use the equation KE= 1/2mass x velocity^2. This means that the amount of kinetic energy an object has (in joules) is equal to half of the mass (in kg) times the velocity (in m/s) squared.

When dealing with objects elevated off the surface of a celestial body (aka objects with gravitational potential energy) we use the equation PE=mgh. This means that the amount of Gravitational Potential Energy is equal to the mass of the object (in kg), multiplied by the gravitational acceleration (in m/s/s), multiplied by the height the object has been elevated to (in meters).

**Activities From Class:**Hi-Ho, Hi-Ho, It's Off to Work We Go!, Do Work!

**Simulations:**Coaster Creator, Energy Skatepark

**Extension Opportunity:**Use google draw to compare two objects (preferably ridiculous scenarios) using the formulas listed in this objective. For example: Which would have more energy- a frozen turkey falling from the top of the empire state building or a car falling from the top of your house? In this scenario, your google draw work would show these two scenarios and the math used to answer the question.

**See Videos Below:**

## Objective 1.2:

**Explain conservation of energy using kinetic and potential energy equations for situations involving energy transfer and transformations.**

Initial Gravitational Potential Energy + Initial Kinetic Energy = Final Gravitational Potential Energy + Final Kinetic Energy

**Summary of Concept:**Energy cannot be created or destroyed, it only changes forms. We can see this mathematically using the KE and PE equations. The overall goal of this would be to compare the amount of gravitational potential energy an object has at the top of a fall to the amount of Kinetic energy an object has at the bottom. The two values will always be the same because ENERGY CANNOT BE CREATED OR DESTROYED!

**Activities From Class:**Hi-Ho, Hi-Ho, It's Off to Work We Go!, Do Work!

**Simulations:**Coaster Creator, Conservation of Energy simulation, Energy Skatepark, Pendulum Simulation

**Extension Opportunity:**Use this gizmo (Username MasonPS Password MasonPS) and create a screencast where you explain the relationship between gravitational potential energy and kinetic energy. Use screencastify to record your verbal explanation while you are moving through the simulation. You can download screencastify from the chrome web store for free!

**See Videos Below:**

## Objective 2.1:

**Calculate work (W) using the equation W = (Force)(Change in position). You may use this equation as long as the force vector and displacement vector are moving in the same or opposite (parallel) direction.**

**Summary of Concept:**Work can be measured using the equation W = F x D any time the force vector and the displacement vector are moving in the same or opposite (parallel) direction. Work is a concept that allows us to investigate the amount of Force that contributed to the displacement of an object. Work is a combination of Newtons and meters. The SI unit for work is a joule ( Newton meter).

**Activities From Class:**What Exactly is Work?

**Simulations:**It's all uphill (work simulation)

**Extension Opportunity:**Mass an object. Displace an object. Video your amazing acting as you displace your object. Make sure the force you apply is in the same direction of the displacement. Film this incredible experience and describe how much work you did in Joules. If you want to be amazing, figure out how far you could have displaced several other items with the same amount of work.

**See Videos Below:**

## Objective 2.2:

**Represent and/ or interpret energy transformations for a phenomenon through a series of pie or bar graphs.**

**Summary of Concept:**Within any activity involving energy we know that the total amount of energy will remain constant. Energy cannot be destroyed, it only changes forms. Pie charts and bar graphs are useful for showing how energy totals remain constant but the forms of energy change.

**Activities From Class:**Wind-Up Toy Demo, Energy Pie Charts, Don't Flinch! Energy Bar Charts, Calculating Energy

**Simulations:**Roller Coaster Energy Transfer, Energy Skatepark, Pendulum Simulation, Chart that Motion

Extension Opportunity:

**Conservation of Energy Exploration (Use screencastify web extension (from the chrome web store) to talk through your conservation of Energy Exploration. Upload the video file to padlet. Your teacher will help you if needed!**

**See Videos Below:**

## Objective 2.2a:

Equations for work, kinetic energy, and potential energy can be combined with the law of conservation of energy to solve problems.

**Summary of Concept:**If an object has 200 Joules of Gravitational Potential Energy at the top of a hill, and all of the energy ends up transforming to Kinetic Energy by the time it reaches the bottom of the hill, you would know that the object had 200 Joules of Kinetic Energy at the bottom of the hill. This knowledge is very powerful when using KE = 1/2 mass x velocity^2 and PE = mass x gravitational acceleration x height. If we were able to calculate the potential energy using the potential energy formula, we could then use that value with the KE formula to identify the velocity of the object. Work, Kinetic Energy, and Potential Energy Formulas all provide us with the units of Joules so we can use the formulas together to solve a variety of problems.

**Activities From Class:**Wind-Up Toy Demo, Energy Pie Charts, Don't Flinch! Energy Bar Charts, Calculating Energy

**Physics Classroom**

Simulations:

Simulations:

**Extension Opportunity:**Create a fictional situation that will allow you to compare work, kinetic energy, and potential energy. Use any method to share your scenario while explaining how the concepts can be mathematically related.

**See Videos Below:**

## Objective 2.2b:

Explain that when energy is transferred from one system to another, some of the energy is transformed to thermal energy.

**Summary of Concept:**Thermal energy is simply the amount of movement within the particles of matter. The more thermal energy an object has, the faster it's molecules (or atoms) will move. The less thermal energy an object has, the slower the molecules (or atoms) will move. Because thermal energy is the movement of molecules, any interaction between two different systems tends to cause a collision between molecules. The collisions between molecules always results in molecular movement and therefore interactions between objects leads to Energy being transformed into thermal energy. Think of it like this... you rub your hands together, your hands heat up. This is because the motion of your hands causes the molecules to interact with each other and speed up. In this sense, the motion in your hands is transformed into thermal energy (aka faster moving molecules).

**Activities From Class:**Wind-Up Toy Demo, Energy Pie Charts, Don't Flinch! Energy Bar Charts, Calculating Energy

**Simulations:**Friction and Temperature

**Extension Opportunity:**Create a top 10 list of things you do that end up creating thermal energy. This could be as simple as touching a tissue to your nose as you blow your nose, or as complicated as converting the fuel in your car into kinetic energy. When finished, post your top 10 list to the padlet.

**See Videos Below:**

## Objective 2.2c:

Explain that since thermal energy involves the random movement of many trillions of subatomic particles, it is less able to be organized to bring about further change. Therefore, even though the total amount of energy remains constant, less energy is available for doing useful work.

**Summary of Concept:**In order for useful work to be done, we must apply our force in the same direction as the displacement we are trying to cause. It is through the purposeful application of force with reference to an intended displacement that we are able to make so many things happen in the world. Our car can go forward because we apply a force in the intended direction of displacement. Sadly, once energy is transferred into thermal energy (the random movement of trillions of subatomic particles) we no longer have much control over the direction of those tiny force vectors. Instead they move in countless different directions. It is for this reason that thermal energy is often considered to be energy that is not completely useful for doing work.

**Activities From Class:**Thermal Energy and Dissipation

**Simulations:**

Extension Opportunity:Film a lab where you convert kinetic energy of an object into thermal energy. You must measure the temperature changes in order to prove that your motion was converted into thermal energy. In the video discuss why the thermal energy is not useful for continuing to do work on the object. When finished post your video to the padlet.

Extension Opportunity:

**See Videos Below:**