Transcript What is Energy? - The NEED Project

EnergyWorks
Yes, indeed it does!
What is Energy?
• Energy is the ability to do work or
cause a change
• Law of Conservation of Matter/Energy
• The more energy matter has, the more
likely it is to be liquid or gas
• “Absolute zero” means no energy – Zero
degrees Kelvin – theoretical because all
substances have some energy
Temperature Scales
100 Celsius Degrees
180 Fahrenheit Degrees
Ratio is
5 Celsius to
9 Fahrenheit
Heat / Thermal Energy
• Thermal energy is the internal energy of
substances
• Causes particle motion
• Temperature ≠ heat!
• Heat is a verb!
• Energy always spontaneously transfers
from high temperature to low temperature
Energy in States of Matter
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Solid
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Liquid
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Gas
Transferring Thermal Energy
Conduction
Convection
Transfer via Direct Contact
Radiation
Transfer via Flowing Fluid
Transfer via Energy Waves
Thermal Energy Transfer Activity
Time to move it move it!
• This is a great way to model conduction,
convection, and radiation
• THIS IS FUN and maybe a little chaotic
• Instructions listed in “notes” with this slide
• Materials needed:
Wadded up scrap paper (lots of it, 2 or 3
pieces per student)
Two buckets
Willing participants
Before We Go Any Further…
Let’s talk about waves!
A wave is a disturbance in a medium. In this case, the
disturbance is the people standing and the medium is the
crowd of seated people.
Light / Radiant Energy
• Light is electromagnetic radiation
– E-mags have an electric field component
– E-mags also have a magnetic field
component
– When one field changes, it changes the other,
propelling itself along.
• Light travels in transverse waves.
• Visible light is a very tiny sliver of the
electromagnetic spectrum
Anatomy of a Transverse Wave
Amplitude
Wavelength
Direction the
wave is
traveling
High frequency, high energy
Low frequency, low energy
The Visible Spectrum
Refraction and Reflection
• Light changes its
direction when
changing medium
(refraction)
• Light can bounce
off a surface
(reflection)
Sound
• Unlike light, sound requires matter to
transmit its energy
• Sound travels in longitudinal waves
• Sound travels better in higher density
materials
• Humans hear sounds from 20 Hz to 20,000
Hz
• Elephants hear sounds from 14 Hz to 12,000
Hz
Anatomy of a Longitudinal Wave
Greater compression indicates higher amplitude
Wave oscillates and
travels in the same
direction
Sounds Reflect Too!
Sounds Reflect Too!
• Sound reflection is called an echo
• Smooth, hard surfaces reflect sound best
• Soft surfaces absorb sound
Motion / Kinetic Energy
• All moving things have kinetic energy
• At NEED, we use the word “motion” when
talking about macroscopic, moving objects
• Moving objects follow Newton’s Laws of
Motion
1. A body in motion stays in motion unless acted on by an
external force. A body at rest stays at rest unless acted
on by an external force.
2. An object’s acceleration is proportional to the force
acting on it.
3. For every action force, there is an equal and opposite
reaction force.
It’s All About Balance
Gravity
Support
Friction / Drag
Support
Propulsion
It Has Potential
• Moving requires energy; the energy of
motion is kinetic energy
• Kinetic energy must come from
somewhere
• Stored energy = Potential Energy
• Much of child’s play involves gravitational
or elastic potential energy
Transformations are Science in
Disguise
• This large rock in Colorado
has gravitational energy.
• A big push would send the
rock tumbling (DO NOT try
this at home, or anywhere
else).
• If the rock falls, the
gravitational energy is
transformed into kinetic
energy as motion.
Growth
Nuclear
Energy
Photosynthesis
6
6
6
Note: Not to scale. 
Respiration
Technology
Electrical Energy
Chemical
Energy
Electrical
Energy
For More Information
The NEED Project
www.need.org
[email protected]
1-800-875-5029
Energy Information Administration
U.S. Department of Energy
www.eia.gov
The NEED Project
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