Energy

Energy Vocabulary energy kinetic Energy potential Energy gravitational potential elastic potential energy mechanical energy joule mass heat law (scientific law) Law of Conservation of Energy energy tranformation

Where does the energy come from? Atoms!!! EVERYTHING and ANYTHING has atoms, molecules, and particles in it. The ENTIRE UNIVERSE is made of atoms These atoms are constantly moving and interacting with each other. This movement allows energy to transfer between atoms.

Proof that atoms exist and they can be moving: DEMO: Dry Ice Are these scissors alive? Does it have atoms? Are they moving? When atoms change temperature they either expand or contract. When they expand they gain energy and when they contract they loose energy, lets observe what happens to different items in dry ice.

A little bit of history The theory of energy was made law in the 19th century when scientists were able to prove that any form of energy can be transformed into another form, but the total energy always remains the same. A theory is an idea that has not been fully proven by science A law has been proven beyond any reasonable doubt and can be repeated and repeated with the same outcome.

Energy Energy occurs in many forms and has the ability to cause change. Therefore, we must remember the Law of Conservation of Energy, that states: Energy can never be created nor destroyed, it can only be changed (transferred)! This process can be witnessed in the following energy transformation of a light bulb: Electrical Energy Light Energy Heat Energy

How is energy transferred? When two substances touch or interact they share energy. One object gains energy and the other transfers it out. In BOTH objects the mass remains the same as only the energy is transferred. Ex. 4 student dominoes line up Ex. Electrostatic generator

Kinetic and Potential Energy Energy that is due to motion is kinetic energy, and energy that is stored and has the ability to move, but is not moving is potential energy. Kinetic energy depends on an objects speed and mass. The faster an object moves, the more kinetic energy it has. The greater the mass, the greater the kinetic energy. If objects collide then the kinetic energy can be transferred from one object to another.

What Is Energy? Kinetic Energy The kinetic energy of an object depends on its speed and mass.

Using SI Units to measure Energy Quantity SI Unit Force Newton Height Meter Work Joule Mass Kilogram Energy

Can We measure kinetic energy? Yes!! We can measure kinetic energy in Joules using the following formula: Kinetic energy = ½ X Mass X Speed2 Let’s try: Energy of a person running 5m/s with a mass of 70kg Energy of a cat jumping around at 2 m/s with a mass of 18 Kg *More practice on pg. 293

Can We measure potential energy? Yes!! We can measure potential energy in Joules using the following formula: Gravitation P= Weight X Height Let’s try: Energy of a person has a height of 5dm with a weight of 70kg Energy of a cat jumping around 2 dm tall with a weight of 18 Kg More practice on pg. 294

What Is Energy? Gravitational Potential Energy The rock climbers have gravitational potential energy, which is potential energy related to an object's height.

What Is Energy? Elastic Potential Energy The energy stored in a stretched object, such as the trampoline, is elastic potential energy. Rank the amount of elastic potential energy of the trampoline from greatest to least.

Using Mechanical Energy An object’s mechanical energy is a combination of its potential energy and both potential energy and kinetic energy. Mechanical Energy = Potential Energy + Kinetic Energy *Practice on page 297

Conservation of Energy Pendulum A continuous transformation between potential and kinetic energy occurs in a pendulum. What are the types of energy the pendulum has at positions A, B, and C?

Conservation of Energy Conserving Energy While You Ride Transformations between potential and kinetic energy occur during a roller coaster ride. How much potential and kinetic energy does the coaster have at each point? Let’s try a real life demo!

Thermal Energy Review Since kinetic energy is measured by the movement of molecules, this is also how we can measure temperature, as the more kinetic energy it has, the higher the temperature will be. We can measure this with a thermometer, by measuring the movement of the molecules either expanding or contracting.

Thermal Energy (cont.) Heat and thermal energy move the same as the energy from a substance moves from higher temperatures (warmer) to lower temperatures (colder). Burning fossil fuels produces thermal energy that is used to boil water and produce steam Thermal Energy can transfer heat in three ways: conduction, radiation, and convection. Can you remember what each transfer of Thermal Energy involves and give an example of each?

Using Nuclear and Chemical Energy Nuclear energy is stored chemical energy. Ex: The Sun Chemical energy can come from any of the following: Food Muscle Use Any other uses you could think of?

Using Radiant Energy Radiant energy is from any form of radiation. A Sun tan - the Sun is transferred into chemical energy on your skin and can get you darker Visible light produces energy you can see Radiant energy can also be transferred into electrical energy(X-rays, gamma rays)

Using Electrical Energy One of the most useful forms of energy Electrical is converted into radiant to provide us with light Converted into thermal to heat up homes/buildings Converted into kinetic to make electric motors move Can come from a Power Plant, car battery, etc. A generator is a device that is used to convert kinetic energy into electrical energy In a power plant, steam is used to spin a turbine which then spins an electric generator

Food Chain When animals eat, they absorb the chemical energy of their prey. Also, when animals decompose their chemical energy is transferred to the soil (humus) and other insects. Even animals go through energy transfers.

Our Body!! When we move, we also use energy! Our whole body uses energy transfers to function: Our cells -> tissues -> organs -> system. When we sweat or shiver our energy is transferred through our body and then to anything we touch (i.e. our clothes, the floor, a person, etc.)

Virtual Lab Fill out your Paper and then wait for the class to be ready to complete the example and virtual lab. Let’s look at a GIZMO example Virtual Lab: Energy Conversions