Two Types of Energy
Kinetic Energy– the energy that an object has because of its motion
Potential Energy– the energy that is stored in an object
Energy is the ability to move or cause change
Usually energy can be observed as motion
Sometimes you cannot observe energy because it is stored in objects
Energy is not created or destroyed – it is
transferred.
Energy that is stored in an object
Potential energy results from the object’s position or to the substances the object is made of
This is the type of energy that can cause motion or some other change
Energy created from movement
Energy often switches back and forth
between potential and kinetic
6 forms
Electrical
Light
Sound
Thermal
Mechanical
Chemical
Which type of energy do plants use during
photosynthesis?
Make a Venn diagram with a partner to
compare and contrast potential and kinetic
energy.
What do potential energy and kinetic energy have in common?
Is mechanical energy a form of
kinetic energy or potential energy?
Which type of energy is a form to potential energy?
According to the table on pg. F8
electrical energy can be transformed
into what types of energy?
How Light Behaves
Light travels in waves that can be reflected, transmitted, refracted, or absorbed by an object.
Vocabulary
Light
Reflection
Refraction
Prism
Light is a form of energy that you can see when it interacts with matter
Light travels in waves
Waves carry energy
A high point of a wave is called a crest and a low point is called a trough.
A wavelength is the distance from one crest
or trough to the next.
Light waves ALWAYS travel in a straight line.
Light waves continue to travel until they strike an object.
If the object is not clear and light waves cannot pass through then a shadow forms behind the object.
Shadows form because objects block the light.
How do light waves travel?
Can light pass through an object?
Why are shadows formed?
When light waves hit an object, the waves can behave in four ways. They can be:
Reflected
Transmitted
Refracted
Absorbed
Reflection occurs when light waves bounce off a surface.
When we see an object, we are actually seeing the light that the object reflects.
Most surfaces reflect at least some of the light that hits them.
Surfaces that are very smooth reflect most of the light waves in the same pattern that it strikes them and this can make them look shiny.
Surfaces that are rough reflect light waves in
many different patterns and this can make
them look dull.
Refraction is the bending of light waves as they pass from one material to another.
Materials that can transmit and refract light include glass, water, and clear plastic.
Refraction can make objects look as though
they are bent or broken.
Some materials take in or absorb most of the light that hits them.
You cannot see light that is absorbed
because it is not reflected back into your eyes.
When light is absorbed, the light energy changes into thermal energy – this is why objects heat up when placed in the sunlight
Dark-colored objects absorb more light than
light-colored objects
The color of light depends on its wavelength.
The color of an object depends on the color of light that it reflects
A prism separates white light into all the different colors in the rainbow.
Raindrops act like prisms when sunlight
passes through them. This is how rainbows
are formed.
What are the four ways that light waves can behave?
In the summer is it better to wear light or dark clothes? Why?
What causes a black road to heat up in the sunlight?
Why do rough surfaces appear dull?
Which material could make light refract:
wood or glass?
What is the difference between reflection
and refraction?
How are raindrops and prisms alike?
What colors does white light consist of?
How does sound behave?
F20-F25
How does sound behave?
Sound is a form of energy produced by vibrations
Vibration is a back-and-forth movement of matter
You can see vibrations when you pluck a stretched rubber band.
You can also hear the sound produced by the rubber band.
When material vibrates it creates sound waves.
As sound waves pass through matter,
particles are first pushed together and then
spread apart.
All sounds are produced by vibrations of matter
When you sing or speak you cause a vibration
in the tissue inside your throat.
How does sound energy travel?
What creates sound waves?
Sound waves have the same properties of light waves and have a wavelength and amplitude.
In a sound wave:
Wavelength is the distance between an area
where particles are pushed together and an area where particles spread apart.
Amplitude is a measure of how close together or how far apart the particles are within each area.
For sound waves
High points represent areas where particles are pushed together
Low points are where particles spread apart.
The greater the amplitude of a sound wave, the more energy it has
When sound waves have more energy, the sound seems louder
Volume is the loudness of a sound
Volume depends on how far the listener is to the sound because the amount of energy in the
sound wave spreads out over more area as the waves move farther from their source.
Frequency is another property of sound waves
Frequency is the number of crests and
troughs produced in a given amount of time, such as a second.
Low-frequency sound produces on a few crests.
High-frequency sound produces many crests and troughs per second.
The frequency of a sound wave determines
the pitch of the sound.
You can change the pitch of a sound by changing the speed at which an object vibrates
Like light waves, sound waves travel away from a sound in all directions.
Unlike like waves, sound waves cannot travel through empty space. They need some type of material to travel through called a
medium.
Sound waves can travel through air, water,
and many solid materials.
How is sound produced?
Write a sentence using vibration and volume.
How does an increase in the amplitude of a
sound wave affect how the sound seems to
the listener?
Thermal Energy
Thermal energy is the kinetic energy of movement of tiny particles of matter.
Thermal energy can be transferred from one
substance to another as heat.
Conduction
Convection
Heat
Radiation
Temperature
Thermal energy
Thermal energy is the kinetic energy of tiny moving particles of matter.
On a cold day the particles in the air have less thermal energy than they have on warm day.
The faster the particles move the more kinetic energy there is an the hotter the object is.
The particles in hot cocoa move faster than the particles in an ice skating blade.
Temperature describes the average kinetic
energy of particles of a substance.
In which object are the particles moving more slowly: an ice cube or your shoe?
Which object has a higher temperature: an ice cube or your shoe?
Why might a cup of cool water have more
total thermal energy than a drop of warm
water?
Thermal energy can be transferred from a warmer substance to a cooler substance.
Heat is a measure of how much thermal
energy is transferred from one substance to another.
Thermal energy can be transferred in two ways:
Conduction – the transfer of thermal energy from particle to particle between two objects that are touching.
Convection – the transfer of thermal energy
through fluids (liquids or gases such as water and air)
When thermal energy is transferred from a substance to your hand, the substance feels warm.
When thermal energy is transferred from
your hand to a substance, the substance
feels cool.
Conduction
Look at the frying pan on page F32 and read to find out how conduction heats up the frying pan and cooks the food.
Convection
Hot air rises and cold air falls
Look at the picture on pg F33 and read about how convection heats the air in the room.
Why does a glass of milk feel cool to your hand?
When you put ice into a glass of warm water, which way does the thermal energy flow?
Why does the handle of a pan on the stove heat up?
Do you think a microwave heats food using conduction? Why or why not?
Why can’t convection occur in solids?
How does heat travel when you cook
vegetables in a hot frying pan?
Heat in the form of radiant energy can travel in waves through empty space.
Radiation is the transfer of energy by waves.
Look at the picture on pg. F34 of the skier
The white snow reflects most of the radiant energy from the Sun and the skier absorbs enough radiant energy from the Sun to stay warm.
When radiant energy is absorbed by matter, it changes to thermal energy.
Radiant energy is also given off by other
sources of heat, such as heat lamps and fires.
You feel the heat when the radiant energy
changes to thermal energy.
When you stand facing a fire, your back may still feel cool. Explain why.
How do you know that the Sun warms Earth through radiation, rather than through
conduction or convection?
List all the ways that thermal energy can be
transferred.
Complete each lesson wrap up on pg F9, F17, F25, F35
Complete the Ch 14 Review and Test Prep on pg F38-F39
Read and review:
Potential and Kinetic Energy
F6-F9
Light
F12-F17
Sound
F20 – F25
Thermal
F30-F35
Read and review:
Potential and Kinetic Energy
F6-F9
Light
F12-F17
Sound
F20 – F25
Thermal
F30-F35
