Transcript Light energy

Chapter 14
Changing Forms of Energy
Energy
• Energy- the ability to do work or
cause a change
• It can change an objects motion,
color, shape, temperature, or
other qualities
• It cannot be created or
destroyed, but can be
transferred to other objects
Examples of Energy Transfer
• A lamp changes electrical energy into light
energy
• Gasoline releases a chemical energy that
moves a car
• Other kinds of energy: Sound, light,
electricity, magnetism, chemical, nuclear,
mechanical, thermal
Kinetic and Potential Energy
• Kinetic: Energy
due to motion
• Potential: Energy
that is not causing
any changes now,
but could cause
changes in the
future
• Read pages 448451
http://www.youtube.com/watch?v=T5WJoup-RD8
Potential and Kinetic Energy
• Potential
– Water behind a
dam
– Battery
• Kinetic
– Water moving
across turbine
blades
A cute picture!
4 Main Types of Energy
•
•
•
•
Chemical Energy
Heat Energy
Light Energy
Mechanical Energy
Chemical Energy
• A kind of potential energy
• Energy caused by chemical reactions
• Examples:
– Cooking food
– Burning something
– Batteries
– Matches
Mechanical Energy
• Mechanical energy is matter in motion.
• An airplane soaring through the sky has
mechanical energy just like the wind or a
flowing river.
• Sound is another type of mechanical
energy.
• Other examples: compressed springs,
stretched rubber bands, bow and arrow,
hammer and nail
Thermal (Heat) Energy
• The total of all the kinetic
and potential energy of
the atoms in an object
• When any forms of
matter gets warmer, the
object’s thermal energy
increases
Thermal (Heat) Energy
• Energy pushed into motion by heat
• Examples:
– Insulation
– Refrigerators
– Air conditioners
– The Sun
– Stove
Conduction, Convection, and
Radiation
• Read page 465 in your book
Conduction
• The flow of heat between objects that are
touching
Convection
• The movement of warm liquids or gases to
cooler areas
Convection
Radiation
• The movement of energy by electromagnetic
waves
Light Energy
• Travels in waves
• It is Electromagnetic Radiation – a
combination of electrical and magnetic
energy
• Look at the pictures on page 458 & 459
Light Energy
• Light energy comes from the Sun. Plants
use it to make food and scientists use it to
create lasers.
• Examples:
– Light bulb
– Fire
– The Sun
– Flashlight
– Firefly/Lightning bug
Let’s look at how lenses can bend
light!
Concave and Convex Lenses
Concave Lens
• Light is bent outward
• Makes objects look smaller
Convex Lens
• Bends light rays to make objects look larger
• Thickest in the middle
• Magnifying glass is one example
Here’s a short word from our
friend, Bill!
• http://www.youtube.com/watch?v=fD1544
bM_c4
Major Parts of the Eye
Light Moving Through the Eye
https://www.youtube.com/watch?v=syaQgmxb5i0
Light and Color
• http://www.youtube.com/watch?v=AD1Xic2mn0U
Let your brain rest while you look at this
adorable walrus!
http://studyjams.scholastic.com/studyjams/jams/science/matter/energy-andmatter.htm
Energy
• http://www.youtube.com/watch?v=btLU2lb3-xs
Sound Energy
• Sound is a wave of vibrations that spreads
from its source
• Frequency- how fast particles are vibrating
• Read page 454 and 455 to yourself
• How does your ear work?
– http://www.youtube.com/watch?v=HMXoHKw
WmU8
Sound Energy
http://www.youtube.com/watch?v=lTetdgpu7MU
Now, Let’s Look at a Cute Picture!