Transcript energy - Science for all

Energy Forms and Transformations
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Remember MRS.CENTS
Energy:
Forms and
Changes
Nature of Energy
 Energy
is all around you!
You can hear energy as sound.
 You can see energy as light.
 And you can feel it as wind.

Nature of Energy

You use energy
when you:



hit a softball.
lift your book
bag.
compress a
spring.
Nature of Energy
Living organisms need
energy for growth and
movement.
Nature of Energy

Energy is involved
when:




a bird flies.
a bomb explodes.
rain falls from the
sky.
electricity flows in
a wire.
Nature of Energy

What is energy that it can be
involved in so many different
activities?
 Energy can be defined as the
ability to do work.
 If an object or organism does
work (exerts a force over a
distance to move an object) the
object or organism uses energy.
Nature of Energy
 Because
of the direct
connection between energy and
work, energy is measured in
the same unit as work: joules
(J).
 In addition to using energy to
do work, objects gain energy
because work is being done on
them.
Forms of Energy

The five main forms
of energy are:
Mechanical
 Electromagnetic
 Nuclear
 Chemical
 Heat

Heat Energy



The internal motion of the atoms is
called heat energy, because
moving particles produce heat.
Heat energy can be produced by
friction.
Heat energy causes changes in
temperature and phase of any form
of matter.
Chemical Energy
 Chemical
Energy is required to
bond atoms together.
 And when bonds are broken,
energy is released.
Chemical Energy
 Fuel
and food
are forms of
stored
chemical
energy.
Electromagnetic Energy

Power lines carry
electromagnetic energy into
your home in the form of
electricity.
Electromagnetic Energy



Light is a form of
electromagnetic energy.
Each color of light (Roy G
Bv) represents a different
amount of electromagnetic
energy.
Electromagnetic Energy is
also carried by X-rays, radio
waves, and laser light.
Nuclear Energy
 The
nucleus
of an atom is
the source of
nuclear
energy.
Nuclear Energy


When the nucleus splits (fission),
nuclear energy is released in the
form of heat energy and light
energy.
Nuclear energy is also released
when nuclei collide at high speeds
and join (fuse).
Nuclear Energy
The sun’s energy
is produced from
a nuclear fusion
reaction in which
hydrogen nuclei
fuse to form
helium nuclei.
Nuclear Energy
 Nuclear
energy is the
most
concentrated
form of
energy.
Mechanical Energy
 When
work is done to an
object, it acquires energy.
The energy it acquires is
known as mechanical
energy.
Mechanical Energy
 When
you
kick a
football, you
give
mechancal
energy to the
football to
make it move.
Mechanical Energy
When you throw a
bowling ball, you
give it energy.
When that
bowling ball hits
the pins, some of
the energy is
transferred to the
pins (transfer of
momentum).
Energy Conversion

Changing energy from one form to
another
Energy Conversion

Energy can be changed from one
form to another. Changes in the
form of energy are called energy
conversions.
Energy conversions

All forms of energy can be
converted into other forms.


The sun’s energy through solar cells
can be converted directly into
electricity.
Green plants convert the sun’s energy
(electromagnetic) into starches and
sugars (chemical energy).
Other energy conversions



In an electric motor, electromagnetic
energy is converted to mechanical
energy.
In a battery, chemical energy is
converted into electromagnetic energy.
The mechanical energy of a waterfall is
converted to electrical energy in a
generator.
Energy Conversions

In an automobile
engine, fuel is
burned to convert
chemical energy
into heat energy.
The heat energy is
then changed into
mechanical
energy.
Chemical  Heat Mechanical
Name That Energy Conversion!!!
Trace the energy
States of Energy:
Kinetic and Potential Energy
Kinetic
Energy is the
energy of motion.
Potential Energy is
stored energy.
States of Energy


The most common energy
conversion is the conversion
between potential and kinetic
energy.
All forms of energy can be in either
of two states:


Potential
Kinetic
Kinetic Energy




The energy of motion is called
kinetic energy.
The faster an object moves, the
more kinetic energy it has.
The greater the mass of a moving
object, the more kinetic energy it
has.
Kinetic energy depends on both
mass and velocity.
Potential Energy

Potential Energy is stored energy.


Stored chemically in fuel, the nucleus
of atom, and in foods.
Or stored because of the work done on
it:
Stretching a rubber band.
 Winding a watch.
 Pulling back on a bow’s arrow.
 Lifting a brick high in the air.

Potential Energy

Energy that is stored due to being
stretched or compressed is called
elastic potential energy.
Kinetic-Potential Energy Conversion
Roller coasters work because of the energy that is
built into the system. Initially, the cars are pulled
mechanically up the tallest hill, giving them a great
deal of potential energy. From that point, the
conversion between potential and kinetic energy
powers the cars throughout the entire ride.
Kinetic vs. Potential Energy
At the point of maximum potential energy, the car has
minimum kinetic energy.
Kinetic-Potential Energy Conversions

As a basketball
player throws the
ball into the air,
various energy
conversions take
place.
Ball slows down
Ball speeds up
Mechanical Energy
• It is the energy associated with the motion
and position of an object.
Light/Radiant Energy
• Radiant energy is the energy of
electromagnetic waves. The term is most
commonly used in the fields of solar energy,
heating and lighting, but is also used less
frequently in other fields (such as
telecommunications).
Solar Energy
• Solar energy is radiant light and heat from the
Sun.
Chemical Energy
• Chemical Energy is energy stored in the bonds
of chemical compounds (atoms and
molecules).
Electrical Energy
• Electrical energy is energy that is caused by
moving electric charges.
Nuclear Energy
• Nuclear energy is the energy in the nucleus, or
core, of an atom.
Thermal Energy
• Thermal energy is the energy that comes from
heat.
Exit Ticket
1. What are the energy conversions or transformations in
the video?
Video 1: https://www.youtube.com/watch?v=HtokwFJ6B9k
Video 2: https://www.youtube.com/watch?v=GGgRiR_bCwQ
Video 3: https://www.youtube.com/watch?v=EzY30Ah8bKY
2. Write a brief summary about the various energy
conversion stations we did today. What did you learn about
energy transformations? What were the various energy
stations? What was the purpose of the stations?
Last Review Day
What is a force?
A push or a pull exerted
on an object in order to
change the motion of the
object; force has size and
direction.
Changes
Forces cause changes in
motion.
A force can change
acceleration; can be a
change in the speed or
direction of an object.
Newton
The unit for force is
Newton
Symbol, N
Forces Acting on Objects
All forces act on objects.
Something must receive
the push or pull.
Just because a force acts
on an object doesn’t mean
that motion will occur.
Net Force
The combination of all of
the forces acting on an
object.
Same direction
Forces in the same
direction are added
together to determine the
net force.
Different direction
Forces in opposite
directions are subtracted
to determine the net
force.
Balanced forces
Forces are balanced when
the forces on an object
produce a net force of 0 N.
Balanced forces do not
cause a change in motion.
Unbalanced forces
Forces are unbalanced
when the forces on an
object produce a different
than 0 N.
Unbalanced forces will
cause a change in motion.
Unbalanced forces
Forces are unbalanced
when the net force on an
object is not 0 N.
Unbalanced forces will
cause a change in
motion.
Examples of Balanced
Forces
House of cards
Chair you’re sitting on
Table you lean on
Examples of unbalanced
forces
Action in sports
Pushing your chair in
Sliding your books across
a table.
Calculating Net Force
Let’s talk about motion
How do you describe motion?
What do you need to describe motion?
Motion
Interpreting a distance versus
time graph
This distance versus time graph shows a boat traveling
through a long canal. The boat has to stop at docks for
changes in water level.
1.
How many stops does it make?
Friction
Friction
A force that opposes
motion between two
surfaces that are in
contact.
Source of Friction
All surfaces have hills and
valleys.
When two surfaces are in
contact, the hills and valleys
of one surface sticks to the
hills and valleys of another.
Amount of Friction
Amount of friction depends
on many factors.
Two factors are the force
pushing the surfaces
together and the roughness
of the surfaces.
Amount of friction
More force exerted
causes more friction.
The rougher the surface,
the greater the friction.
Types of Friction
Kinetic Friction
Static Friction
Kinetic Friction
The friction between
moving surfaces.
The amount of kinetic
friction depends on how
the surfaces move.
Examples of Kinetic Friction
Sliding-Brakes on a
bicycle
Sliding-Writing
Rolling-Wheels
Static Friction
Static friction occurs
when a force is applied
to on object but does not
cause the object to
move.
Static vs. Kinetic Friction
Static friction disappears
as soon as an object
starts moving and then
kinetic friction
immediately occurs.
Harmful VS Helpful Friction
Harmful Examples
 Friction causing holes in pants, Wearing down
engine parts
 Reduce by adding a lubricant like oil or ball
bearings
Helpful Examples
 Brakes on a car, Friction lets you walk without
slipping
 Increase by adding roughness or adding force
Work and Simple
Machines
77
What is work?
 In
science, the word work has a
different meaning than you may be
familiar with.
 The scientific definition of work is:
using a force to move an object a
distance (when both the force and the
motion of the object are in the same
direction.)
78
Work or Not?

According to the
scientific definition,
what is work and
what is not?


a teacher lecturing
to her class
a mouse pushing a
piece of cheese with
its nose across the
floor
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80
Formula for work
Work = Force x Distance
 The
unit of force is newtons
 The unit of distance is meters
 The unit of work is newton-meters
 One newton-meter is equal to one joule
 So, the unit of work is a joule
81
W=FD
Work = Force x
Distance
Calculate: If a man
pushes a concrete
block 10 meters
with a force of 20 N,
how much work has
he done?
82
W=FD
Work = Force x
Distance
Calculate: If a man
pushes a concrete
block 10 meters
with a force of 20 N,
how much work has
he done? 200 joules
(W = 20N x 10m)
83
History of Work
Before engines and motors were invented, people
had to do things like lifting or pushing heavy loads by
hand. Using an animal could help, but what they really
needed were some clever ways to either make work
easier or faster.
84
Simple Machines
Ancient people invented simple
machines that would help them overcome
resistive forces and allow them to do the
desired work against those forces.
85
Simple Machines
The six simple machines are:

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
Lever
Wheel and Axle
Pulley
Inclined Plane
Wedge
Screw
86
Simple Machines
A
machine is a device that helps make
work easier to perform by
accomplishing one or more of the
following functions:




transferring a force from one place to
another,
changing the direction of a force,
increasing the magnitude of a force, or
increasing the distance or speed of a
force.
87
Mechanical Advantage
 It
is useful to think about a machine in
terms of the input force (the force you
apply) and the output force (force
which is applied to the task).
 When a machine takes a small input
force and increases the magnitude of
the output force, a mechanical
advantage has been produced.
88
Mechanical Advantage




Mechanical advantage is the ratio of output force
divided by input force. If the output force is bigger
than the input force, a machine has a mechanical
advantage greater than one.
If a machine increases an input force of 10 pounds
to an output force of 100 pounds, the machine has a
mechanical advantage (MA) of 10.
In machines that increase distance instead of force,
the MA is the ratio of the output distance and input
distance.
MA = output/input
89
The Lever



A lever is a rigid bar
that rotates around a
fixed point called the
fulcrum.
The bar may be either
straight or curved.
In use, a lever has both
an effort (or applied)
force and a load
(resistant force).
90
Wheel and Axle


The wheel and axle is a
simple machine
consisting of a large
wheel rigidly secured
to a smaller wheel or
shaft, called an axle.
When either the wheel
or axle turns, the other
part also turns. One full
revolution of either part
causes one full
revolution of the other
part.
91
Pulley

A pulley consists of a
grooved wheel that turns
freely in a frame called a
block.
 A pulley can be used to
simply change the direction
of a force or to gain a
mechanical advantage,
depending on how the pulley
is arranged.
 Fixed vs. Movable pulley
Inclined Plane

An inclined plane is
an even sloping
surface. The
inclined plane
makes it easier to
move a weight from
a lower to higher
elevation.
93
Inclined Plane


The mechanical
advantage of an
inclined plane is equal
to the length of the
slope divided by the
height of the inclined
plane.
While the inclined plane
produces a mechanical
advantage, it does so
by increasing the
distance through which
the force must move.
94
Although it takes less force for car A to get to the top of the ramp,
all the cars do the same amount of work.
A
B
C
95
Inclined Plane

A wagon trail on a
steep hill will often
traverse back and forth
to reduce the slope
experienced by a team
pulling a heavily loaded
wagon.

This same technique is
used today in modern
freeways which travel
winding paths through
steep mountain passes.
96
Wedge

The wedge is a modification
of the inclined plane.
Wedges are used as either
separating or holding
devices.

A wedge can either be
composed of one or two
inclined planes. A double
wedge can be thought of as
two inclined planes joined
together with their sloping
surfaces outward.
97
Screw
The screw is also a
modified version of
the inclined plane.
 While this may be
somewhat difficult
to visualize, it may
help to think of the
threads of the
screw as a type of
circular ramp (or
inclined plane).

98
99
Learning Targets:
Define electron and electricity.
Define contact point.
Create circuits using a D-battery, wire and flashlight bulb.
Explain what is required to allow for the flow of electricity.
Is electricity important?
What are a few things that we use
electricity for?
How would the world be different
without electricity?
https://www.youtube.com/watch?v=Mrt5_6-BFi8
We know matter is made up of
atoms.
 Each atom contains protons,
neutrons, and electrons.
 Protons are positively charged.
 Neutrons are neutral.
 Electrons are negatively charged.
 If the number of protons in an atom
equal the number of electrons then
it is balanced. (example = carbon)
 Electrons can move from one atom
to another making the atoms
positively or negatively charged.
 A current of electricity is created
when electrons move between
atoms.
 Electricity is the flow of electrons.
 Materials that want to hold on
to their electrons and restrict
the flow are insulators.
 Examples
 Rubber, plastic and wood
 Materials that loosely hold on to
their electrons and easily allow
the flow of electrons are
conductors.
 Examples:
 Metal(iron, steel, copper), water,
people
https://www.youtube.com/watch?v=RQ3djo
s_LY8&app=desktop
 Circuits are a “bridge” between the
negative electrons and the positive
atoms.
 Connecting a wire to create the
bridge allows the flow of electrons
from the negative end to the
positive end.
 Think of a draw bridge.
https://www.youtube.com/watch?v=GgrCCfL5xjo
 A contact point exists where a
conductor (ex. wire) is in contact
with another conductor to allow the
flow of electrons.
 Where were the contact points in
your circuits?
 Battery-positive and negative ends
 Bulb-side and bottom

You will need two pages in your SISN to
complete the next part of our class.




In your bags you have: 3 wires, a D battery, a
battery holder, a switch, and a light board.
Arrange these materials in a way that you
think you will make the light bulb glow.
Use ALL materials with respect! Do NOT use
the materials in an inappropriate way.
When you have made the light bulb turn on,
draw what you have done in your SISN.
Please get this into
your notebook and
then we will put
one more chart in
your notebook.
 The word “magnet” is derived
from Magnesia which is a region
in Greece.
 The region contains dark,
metallic rocks called lodestones,
which are a kind of magnetite.

Use the chart
below to
brainstorm what
you already know
about magnets.

You will have 3
minutes to
complete the
brainstorm.
 The Earth has magnetic poles,
north and south.
 The magnetic north pole is
currently moving toward Russia at
a rate of 40 miles per year.
 The actual north/south magnetic
poles are not at the north and
south poles. They are continuously
moving.
 Most individual magnets have
two magnetic poles.
 Like poles repel each other;
unlike poles attract each other.
 A magnetic field exists in the
magnet and in the space around
it.
 Gravity and magnetism are both forces
and can affect objects at a distance,
but they are two separate things.
 Gravity occurs between two objects
and magnetism depends on the
property of objects.
 Gravity is a stronger force than
magnetism.

http://van.physics.illinois.edu/qa/listing.php?id=19810



Magnets
Directions: Work through each part of the
activity and follow each set of directions.
Materials: ring magnets, bar magnets, umagnets, paper clips, pencil
PART 1: MAGNETIC POLES
Fill in the chart describing the results of the following
combinations. What happens when you put the north
pole of one magnet with the north pole of a second
magnet?
N/N
N/S
S/S
PART 2: FLOATING MAGNETS
Procedure: Arrange the ring magnets on a pencil in multiple ways
to discover which ways will allow the magnets to float on the
pencil. Arrange various numbers of magnets in various ways. Draw
and label three different combinations of magnets on the pencils.
1.Why does the magnet float on one side and not the other?
2.What would happen if the pencil were not there?
3.What happens to the spaces between the magnets as you add
more?
4.Why do the magnets float?