Transcript Energy

WARM-UP 4/4/14
• Teach the Teacher: How was the test
on a scale from 1-10 (1 easiest thing
ever, 10 being hardest)
• Review: What is inertia?
WARM-UP 4/6/14
Teach the teacher: Ghosts; possibility
or fiction?
Review: When did the skater have
kinetic and Potential energy? SKate
park
EVERY CHANGE
THAT OCCURS
REQUIRES
ENERGY!
ESSENTIAL QUESTIONS
• First Chapter: How do we describe
Motion?
• Last Chapter: why do things move the
way they do?
• This Chapter: What is energy, and what
happens as it get used?
Define and calculate work and power.
LEARNING TARGETS
- Describe a situation in which energy
causes a change.
- Describe the relationship between
potential and kinetic energy.
- Calculate gravitational potential and
kinetic energy.
- Describe how energy is conserved and
changes forms
MAIN IDEAS
• Every change that occurs requires
energy.
• There are different forms of energy,
including potential energy and kinetic
energy.
• Energy cannot be created or destroyed
but only can change from one form to
another.
ENERGY
Energy—The ability to cause change and the ability to do
WORK
An object has energy if it is moving, or it can also have stored
energy.
There are many forms of energy:
• Electrical: energy due to the movement of
electrons
• Chemical: energy stored in the bonds
between atoms
• Thermal: energy from heat
• Radiant – Light: energy from the sun & light
• Sound: the energy of vibrating sound waves
• Magnetic: energy of magnetism
• Mechanical: Kinetic + Potential
Nuclear: potential energy stored in the
nuclei of atoms
NUCLEAR ENERGY
• There are two types of nuclear energy
• Fission and Fusion
• Both forms energy are stored as mass in the atoms of
certain elements. This mass can be changed into
energy under the proper conditions according to
Albert Einstein's famous equation:
• Fission cartoon
• nuclear fission
• nuclear fusion
FISSION
• Fission the 2nd form of nuclear
energy
• The exact opposite of fusion.
• In fission atoms are broken
apart.
• In fission heavier elements form
lighter elements.
• Uses
• Hydrogen Bomb
• Nuclear Energy Plants
FUSION
• Fusion atoms are
"fused" together
• In fusion lighter
elements form
heavier elements
• Uses
• The middle of stars
ENERGY IS LIKE MONEY
• Money
• Different forms of money:
dimes, dollars, checks,
credit Cards, etc.
• You can save money,
spend it, change it into
different kinds of
money…. But money is
money
• Energy
• Different forms of
Energy: Chemical,
nuclear, etc.
• You can save energy
(batteries & potential
energy ), you can
“spend” energy (kinetic
energy), etc.
WARM-UP 3/19/2013
• Teach the Teacher: What is the most
annoying sound?
• Review: Which has more inertia, a
booger or a big slug?
WARM-UP 3/19/13
• Teach the Teacher: Would you rather watch
someone do an awesome jump (skiing,
skateboarding, etc.) or someone falling,
tripping etc.
• Review: Without air resistance, what will hit the
ground first after being thrown off a building: a
2lb. chocolate bunny or a peep?
WARM-UP 3/28/13
• Teach the Teacher: What is the best
Saturday morning cartoon?
• Review: If a piece of cheese is dropped
from a second story building into my
mouth, what will stay the same as it
falls.
KINETIC ENERGY
• KE is energy of motion.
• KE = ½ mv2
• m = mass (kg)
• v = velocity (m/s)
• SI Unit for Energy is Joule
• Joule = kg m2/s2
POTENTIAL ENERGY
• PE is energy that is stored in
an object.
3 types of PE
Elastic PE
• Energy due to a
stretch or
compression
2. Chemical PE
• Energy in the bonds
between atoms
1.
3. Gravitational
PE
• Energy due to an
elevated position
• GPE = mgh
• m = mass
g = gravity=9.8
m/s2
• h = height
MECHANICAL ENERGY
• Many different situations where
energy changes quickly back and
forth
• Ex: skateboarder on a ramp, roller
coasters, other
examples___________
• Mechanical Energy is the total
amount of kinetic and potential
energy in system
• ME=PE + Ke
WILL MECHANICAL ENERGY
CHANGE?
A .05 kg apple is 30m in the
air
GPE=.05kg*9.8m/s/s*30m=
14.7 J
What is it at 20m?
GPE=.05kg*9.8m/s/s*20m=
9.8 J
What is it at 10m?
GPE=.05kg*9.8m/s/s*10m=
4.9 J
• All falling objects
speed up as they
fall (accelerate at
9.8m/s/s), so with
KE=.5m*v2 then KE
gets larger as the
apple falls
• So if PE is
•
& KE is
• Then does
mechanical energy
change?
• NO!
WARM-UP 3/21/13
• Teach the Teacher: What is the best part about
spring?
• Review: The fact that when a zebra is
pushing off the ground, the ground is
pushing back on the zebra is which
one of Newton’s Laws?
WARM-UP 3/22/13
• Teach the Teacher: Would you rather
go to an amusement park or go to a
water park?
• Review: A boulder that is teetering on
top of hill..does it have potential energy
or kinetic?
FLASH CARD
• On the Back
• On the Front:
• Gravitational
Potential Energy
• GPE, potential
energy due to
position because of
gravity
GPE=mhg(9.8)
LAW OF CONSERVATION OF ENERGY
• Energy can not be created nor
destroyed, it just changes form.
• Rollercoaster
• mass and spring
• Challenge: Try and think of a time that
energy seems to go away?
HOW DOES THE HUMAN BODY
BALANCE ENERGY?
• Eat Cheese
• Run to get more
cheese
• Feel warm
• Chemical Energy
• Create Kinetic and
Thermal energy
• Heat is transferred to
air
WARM-UP 3/25/13
• Teach the Teacher: What is one of the worst
things you have learned about in history (you
could give an example of a war, genocide,
natural disaster, etc.)
• Review: Which would have the most potential
energy, a puppy on a chair, a puppy on a table,
or a puppy running on the floor?
FLASH CARD
• On the Front:
• Mechanical Energy
• On the Back:
• ME, the kinetic and
potential energy
• ME= KE + PE
FLASH CARD
• On the Back:
• On the Front:
• Law of
Conservation of
Energy
• LOCOE, energy is
neither created nor
destroyed it
changes forms
WARM-UP 3/26/13
• Teach the Teacher: If you could be in
any type of competition what would
you want to do?
• Review: What two things equal
mechanical energy?
WARM-UP 3/27/13
• Teach the Teacher: If you had to write a
thank you card to someone right now
who would it be to?
• Review: When a skater goes up a ramp
what does it’s kinetic energy change
to?
WARM-UP 4/2/13
• Teach the Teacher: What is the best
April Fool’s joke you have ever heard
of?
• Review: What are all the ways that
the sun’s energy is used?
WARM-UP 4/3/13
• Teach the Teacher: Who is the most
inspirational person?
• Review: What are the units for
energy?