Energy

Question What does it mean when we say “that kid has a lot of energy?” It means that kid is “Active” and moving. How does that relate to work?

Energy How can you tell if someone has a lot of energy? How does that relate to work?

Work = Energy Work Energy: Moving an object by pushing it. a transference of energy Energy: The Ability to do work (move both large or small objects) It’s what causes change.

Force & Work

Work = Energy Notice that the formula’s for both work and energy are exactly the same with the exact same unit (J – Joules)

Two Types of Energy Potential – Stored Energy (NOT in motion) Depends on the objects position or shape Kinetic – Energy in motion Depends on mass & velocity of an object

6 Forms of Energy Mechanical (Physical Moving Objects) Large Objects Mechanical (Physical Moving Objects) Gravitational Elastic (Spring) Sound (Oscillation of air molecules) Heat (Kinetic Energy of Whole Motions of Atoms) Light (Photon Oscillations of Electric and Magnetic Fields) Chemical (Potential Energy in the Bonds between Atoms) Electrical (Kinetic Energy of Electrons found in Atoms) Nuclear (Potential Energy in the Bonds of Protons in the Nucleus) Atomic Sized Objects

Mechanical Energy Moving large objects.

Three Forms of Mechanical Energy Gravitational Elastic Sound

(work = Force x Distance) Mechanical Energy Gravitational Energy: Gravity making the object move. Potential Energy PE=mgh Kinetic Energy KE=1/2mv2 Work = Weight x Height (work = Force x Distance)

Mechanical Energy Elastic Energy: movement caused by bending or distorting. EKE = ½ mv2 EPE = kd2 Work = Force x Distance

Mechanical Energy Sound = Movement of air back and forth as the wave goes through. Work = Force x Distance

Energy Due to Motion of Atomic sized particles

Heat / Thermal Energy = Heat Energy: (Thermal) Movement of the Whole atom. (average kinetic energy) Heat Energy is the form of energy that is related to the motion of atoms Measurement of total movement of molecules (Kinetic Energy) Heat energy is measured by “Temperature” So a higher temperature simply means that the atoms are hitting the thermometer fast & more often Liquid A Liquid B A higher temp. means more Kinetic Energy for the molecules! Think: Which of the two liquid samples has a higher temperature? WHY? Work = Force x Distance

Heat / Thermal Energy Heat or Thermal Energy: is the kind of energy that is related to and/or caused by fast moving particles that make up the material. Though lava moves fairly slow, the particles are moving very fast. If you were to touch a desk, the interior is moving fairly rapidly – though the outside appears to have no motion at all. Mechanical energy can transfer into heat: try rubbing your hands. The friction from the surface of your hands from rubbing them back and forth create heat.

Light Electromagnetic (AKA – Light): Movement of charged particles which induce WAVES of Electromagnetic radiation – AKA photons of Light! Electromagnetic radiation can be described in terms of a stream of photons, which are massless particles each traveling in a wave-like pattern and moving at the speed of light. Each photon contains a certain amount (or bundle) of energy, and all electromagnetic radiation consists of these photons. The only difference between the various types of electromagnetic radiation is the amount of energy found in the photons. Radio waves have photons with low energies, microwaves have a little more energy than radio waves, infrared has still more, then visible, ultraviolet, X-rays, and ... the most energetic of all ... gamma-rays. The electromagnetic spectrum can be expressed in terms of energy, wavelength, or frequency. For more information, go to: http://imagine.gsfc.nasa.gov/docs/science/know_l1/emspectrum.html Animation Credit for Electromagnetic radiation: http://hawkins.pair.com/eRadiation.html#We%20Have%20Radiation! Also: Moody, J. (2005) Physical Science Principles, BYU College of Physical & Mathematical Sciences, pg 133,

Light Energy from the motion of a moving charged particle in the atoms disturbs the electromagnetic fields which effects other charged particles in other atoms. Electromagnetic Fields Radiation +/- +/- Work = Force x Distance

Light Spectrum

Examples

Chemical Energy stored in the bonds between the atoms. C C Demo: hold hands & snap release Work = Force x Distance

Chemical Gas Work = Force x Distance Have a few students describe the Magetix ball & magnets, then compare that to chemical energy Work = Force x Distance

Electric Energy: Electrical Energy: Motion (flow) of Electrons Work = Force x Distance Electrical Energy: Motion (flow) of Electrons These charges can be made to move through a wire Electric energy “flows” through wires to our houses where we plug stuff in! Electricity is electric energy Lightning is Electric energy

Other Examples of Electric Energy

Electrons from the outer edges of the Atom Electrical Energy Comes from the movement (or flow) of Electrons from the atom Electrons from the outer edges of the Atom Work = Force x Distance

Nuclear Energy Energy stored in the bonds of protons in the nucleus. Comes from the Stored Energy from the Nucleus of the atom Energy stored in the bonds of protons in the nucleus. Nucleus of the Atom: Protons & Neutrons Work = Force x Distance

Nuclear Energy - Fission Demo: Break hands apart – point out the release of energy from the break Work = Force x Distance

Nuclear Energy - Fusion AKA Solar Energy Demo: Clap – point out the release of energy from the collision Work = Force x Distance

Acronym Original List MECH-’n Legs Moving Large Stuff Mechanical Grav, elast, sound Moving Atomic Stuff Heat Light Chemical Electrical Nuclear MECH-’n Legs Mechanical Electrical Chemical Heat Nuclear Light elastic gravitational sound I will wait for the sumo industrial strength walker

Energy Defined Example Mechanical Any Large Object Moving – Forwards/Backwards/Up/Circle Car, Generator, ball, fan, blender, motor Electrical Any shock, zap, lightning’ish phenomenon Outlet, Battery, Lightning Chemical Any chemical reaction, fuel or explosion. Gas, food, sugar, fire Heat Anything that’s hot/cold CCR Light bulb, fire etc. Nuclear The sun Light Duh. Any form of radiation. ROY G. BIV, radio, mw, IR, VL, UV, XR, Gma Elastic Any bending, twisting or stretching of an object. Bending Ruler, stretching a rubber band. Gravitational Any falling object. Pendulum, falling ball. Sound Any noise. Rock concert.