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Physical Science
Chapter 16
Grade 5
Chapter 16- Energy and Waves
Lesson 1- Kinetic and Potential
Energy
►Forms of Energy
 Energy is the ability
to do work
► Measured in Joules
Energy comes in
different forms such
as: Thermal,
chemical,
electromagnetic,
electrical and
mechanical
►
► Thermal
Energy- is the motion of the particles in
matter, felt as heat
► Electromagnetic energy is visible light,
microwaves, radio waves and X-rays
► Chemical Energy- can be released during a
chemical reaction, like burning coal, or a battery in
a toy car.
► Electricity – movement of charges particles.
Powers almost everything in your house.
► Mechanical Energy- energy an object has
because of its motion or position
 Wind, sound, or falling objects
Answer this:
► If
a Large Rock is on the edge of a cliff, what kind
of energy does it have?
Answer
► Potential
Energy
Mechanical
Kinetic Energy
► Kinetic
Energy- energy
of movement.
► Any moving object has
kinetic energy
 A bowling ball rolling
down an alley
 Falling rock
 Vibrating object
Potential Energy
► The
energy an object
has stored is Potential
energy.
 Rock on a ledge
 Compressed spring
 Rubber band being held
► When
work is done,
energy transfers from
one form to another
► Example:
An archer
pulls back the bow and
arrow. The bent bow
has stored POTENTIAL
energy. When it is
released, the energy is
changed to Kinetic,
mechanical energy.
Calculating Mechanical Energy
► When
an object with Potential energy starts
to move, some of that energy is changed to
Kinetic energy
► As the amount of Kinetic energy increases,
Potential energy decreases
► Mechanical Energy- is the SUM of PE and KE
 In a falling object, PE and KE will change, but
ME will stay the same.
Lesson 2- How Are Sounds Made
Sound Production
►
►
A mechanical wave forms when
energy moves through a
medium or matter.
Transverse Waves move
perpendicular to the direction of
the wave
 Waves in a jump rope
►
Longitudinal Waves move
parallel to the direction of the
wave
 A slinky moving back and forth,
 Where particles come together
they form compressions
Waves
► Waves
are measured by two things:
► Amplitude- how high a wave is from crest to
trough, (top to bottom)
► Wavelength- the distance between two
waves
► Scientists also measure frequency, or how
many waves pass per second
 Shorter wavelengths have higher frequencies
 Longer wavelengths have lower frenquencies
Sound Waves
►
Sound waves are produced
through vibrations
 The energy of the vibrations
travels through the medium as a
longitudinal wave.
►
Waves travel at different
speeds through different
materials.
 Metals vibrate more easily than
rubber. Ex: Tuning forks
 Sound waves move faster through
solids and liquids than through
gases
Pitch
► The
properties of sound depend on the
vibrations produced
► Pitch is how high or low you perceive an
object to be
 Depends on the wave’s frequency
 Higher frequency, higher pitch (whistle)
 Lower frequency, lower pitch (tuba)
Volume
► Volume-
strength of a
vibration causing a
sound to be loud or
soft
► Sound is measured in
decibels
Acoustics
► Sound
waves can behave
differently when they hit different
materials
► Acoustics is the study of how
materials affect sound waves
 A sound wave will reflect off hard
surfaces
► Grand
Canyon echoes
 Sound waves are absorbed by most
soft or porous surfaces
► Cotton
rooms
and other materials in recording
Lesson 3- Properties of Light
Electromagnetic Waves
► Light
Waves are electromagnetic waves
 Can travel through a medium or vacuum
 Examples include: x-rays, gamma rays, UV rays,
visible light
► Different
EM waves have different
frequencies and wavelengths
► Visible light is seen by humans
 Consists of seven different colors
► Some
waves can be
harmful to living things
► EM waves interact
differently with
different materials
 Some materials will
reflect certain
wavelengths of color,
and absorb others.
 Example: Apple reflects
red and absorbs other
colors
Reflection and Refraction
► Light
can be absorbed, reflected or
refracted as it hits an object
► Reflection occurs when a wave bounced off
a material
 Ex: looking in a mirror
► Refraction-
when the path of light changes
from one material to the next
 Ex: a pencil looking “broken” in a glass of water
A convex lens beds
light rays toward one
another.
► A concave lens bends
light rays away from
one another.
► People with glasses
use different lenses to
refocus light and
images onto the retina
►
Fiber Optics
► Fiber
optics use total
internal reflection
 Has helped to improve
communication systems
and medical procedures
 Optical fibers can
transmit light over long
distances