Chapter 3: ENERGY New Notes 3.1: Energy exists in Different Forms - - PDF document

Energy, Waves, Light and Sound 1

Chapter 3: ENERGY

New Notes 3.1: Energy exists in Different Forms

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Energy Form Description Example or Use Mechanical Energy that moves object Turn a car key Sound Vibrations in the particles of a solids, liquids or gasses Cannot travel through empty space Singing, laughing Chemical Energy stored in the structure of matter Food, gasolineWood (burn to use) Thermal(heat) Total amount of energy from the movement of particles that make up matter HEAT Electromagnetic (waves) Transmitted through empty space in the form of waves. Visible light, x­rays, gamma rays, microwaves, radio waves Nuclear The energy stored in the nucleus of an atom Sun­ fusion (put together) of 2 nucleiFission break apart the nucleus of an atom

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Home Work: Monday: 3.2 Reading Study Guide and pg 83 1­4 Tuesday: Study For 3.2 Quiz Wednesday:3.2 Quiz , Read Study Guide 3.3 Thursday: Study for 3.3 Quiz Friday: Study for 3.3

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New Notes 3.2: Energy Can Change Form But is Never Lost.

• A. The Law of Conservation of Energy

States that energy can not be created

• r destroyed it is transferred into

another form.

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• B. Kinetic energy can be converted into

potential and potential energy can be converted back into kinetic energy

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• C. Energy Efficiency is the measurement
• f usable energy after an energy

conversion has taken place.

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Review 3.2: A.The measurement of usable energy after an energy conversion is ________________.

• B. Energy _______________________may

produce __________________forms of

• energy. For example the shaking of a fan

(kinetic energy) or heat energy

• C. Describe the motion of a roller coaster.

When is there max. potential, max kinetic and what conversions take place .

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Review 3.2: A.The measurement of usable energy after an energy conversion is energy efficiency.

• B. Energy conversions may produce

unwanted forms of energy. For example the shaking of a fan (kinetic energy) or heat energy

n

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WAVES, LIGHT, SOUND

1.1 Vocabulary:

Wave A disturbance that transfers energy Medium material that a wave travels through (earth, water, air, rope etc) Mechanical Wave waves that transfer energy through matter. Ex: sound, water, earthquake Transverse Wave Wave travels up and down or left to right. Ex.

• cean wave. Wave travels perpendicular (at

right angles) to the disturbance. Longitudinal Wave (compression waves) The wave travels back and forth in the same direction as the disturbance. Ex. sound waves

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1.2 Vocbulary

Crest The highest point on a wave Trough The lowest point on a wave Amplitude The distance a medium moves above or below its resting point Wavelength the distance from one crest or trough to the next crest or trough Frequency the number of wavelengths passing through a fixed point in a certain amount of time. Frequency determines the pitch of a sound wave Reflection The bouncing back of a wave after it strikes a barrier Refraction The bending of a wave as it enters a new medium at an angle other can 90 degrees. Diffraction The spreading out of waves as they pass through an opening or around the wedges of an

• bstacle.

Interference The meeting and combining of

• waves. Adding or subtracting of

waves amplitudes.

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Sound sound is a longitudinal wave that is produced by a vibrating object that travels through nature Vibration a rapid back and forth motion Vacuum is empty space. Light can travel through a vacuum, sound can not. Pitch The quality of highness or lowness of a sound determined by the waves frequency Electromagnetic Waves A wave that does not require a medium to travel travel (can travel through empty space). Examples: radio, light, gamma, microwaves, ultra violet, visible light Radiation energy that travels across distances in the form of electromagnetic waves Bioluminescence The production of light by living organisms. Luminescence The production of light without the high temperature needed for incandescence

Energy, Waves, Light and Sound 15 Lense is a clear optical tool that refracts light Concave Lense light rays will spread out Convex Lense light rays bend and meet at a focal point

Waves transfer energy A wave is a disturbance that transfers energy from one place to another Forces are required to change the motion of an object. Therefore forces are required to make disturbances and cause a wave.

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Rope Wave: when you pull on a rope it send a wave through the rope Water Wave: Dip your finger or foot into the water it makes a ripple, which is a wave traveling through the water

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Earthquake Wave: When plates in the earth crust move, the sometimes push and pull on each other, causing energy to be

• released. That energy travels as an S or a P wave. As waves

move through the ground the energy causes the earth to shift and shake.

Waves are also classified based on how they

• move. They can move up and down or side

to side (Transverse Waves) or they can move back and forth (Longitudinal Wave).

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Parts of Waves:

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Mediums: Many waves must travel through a substance called a medium. When waves pass through different mediums sometimes it can change the

• wave. The medium often determines how a

wave behaves.

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Certain mediums can slow down a wave, or speed up a part of a wave causing the wave to bend or refract. For example when light wave pass from air into water, the wave slows down and bends or REFRACTS, distorting the image that we see.

REFRACTION:

REFRACTION: BENDING

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REFRACTION: BENDING Sometimes we use a LENS to refract (BEND) light on purpose.

LENSES:

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A Concave Lens: produces a smaller image Concave Lens can "Shrink the image"

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A Convex Lens: magnifying glass, can invert (make upside down) the image or make the image appear larger like a magnifying glass

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REFLECTION:

REFLECTION: Some substances act as a barrier and waves can not travel through them. Instead waves will bounce off the barrier. This is called REFLECTION. That means the wave bounces back in the opposite direction it was traveling. Like light on a mirror will be reflected.

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Examples: 1.The moon does not produce any light of its own. Instead is appears bright in the sky because the moon's surface is reflecting the light waves that are coming off the SUN. Examples:

• 2. SOUND waves can reflect off a mountain to

create an echo. Using different types of mirrors can reflect light in certain ways

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Convex Mirrors ­ will make the image look smaller because the light waves move away from each other Concave Mirrors ­ will make the image look upside down and smaller if the mirror is far away, if the mirror is up close the image will look much larger.

Diffraction: Waves can also diffract when the reach a new medium with a hole or an opening. This means that the waves will spread out or DIFFRACT. DIFFRACTION is the spreading out of waves through an opening or around the edge of an

• bstacle.

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INTERFERENCE: Waves can also pass through each other and combine. This is called interference.

S O U N D

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SOUND: Sound is a type of MECHANICAL wave Sound is a type of LONGITUDINAL wave Sound waves must be transferred through a medium (matter) unlike light they CAN NOT travel through empty space.

Producing Sound: waves must cause a medium to vibrate. Sound is produced in the body in your LARYNX ­ the area that is home to the vocal chords. When you speak muscles push air from your lungs through the LARYNX. This air causes those vocal chords to vibrate. When the vocal chords vibrate sound is heard. This is similar to how hammers inside a piano hit strings, causing the strings to vibrate and produce music.

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Hearing Sound: Sound waves come into your ear and hit your ear drum, causing the thin membrane on the ear drum to vibrate. Then those vibrations are transferred farther into the middle ear causing 3 tiny bones to vibrate (hammer, anvil, and stirrup). The inner ear called the cochlea ­ contains tiny little hairs. The vibrations make those tiny hairs bend. When those hairs bend and electric signal is sent to your brain registering as sound.

Pitch: some sounds have a very high quality while others sound very low. This is called a sounds pitch. It is determined by the frequency

• f the sound wave. The more waves that pass

through your ear drum the higher the pitch.

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High Pitch: Objects that vibrate very fast: have high frequencies, and short wave lengths Low Pitch: objects that vibrate slow: have low frequencies, long wavelengths

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Sound saves that are above what a human can hear are called ULTRASOUND. Ultrasounds are used to detect objects. A mother can see an image or her unborn baby by using ultrasound waves.

Sound Waves: Sound Waves:

They can be used to detect objects underwater, or inside the body. Bats use reflected ultrasound waves, echoes, to find

• food. Humans use Sonar the same way

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The Doppler Effect: When an object is moving closer or farther away from you the wave is distorted and it distorts the pitch. As something gets closer to you the pitch increases, as something moves away from you the pitch decrease.

The Electromagnetic Spectrum:

­ Visible and Invisible Light Spectrum arranged by wavelength ­ Waves that can travel through empty space ­ Radio Waves, Microwaves, Infrared Waves, Visible Light, Ultraviolet Light, X­Rays, Gamma Rays ­ The only light that a human can see is visible light ­ which is a collection of all the colors of light making white light The colors of light organized by decreasing wavelength: (longest­­> shortest) Red, Orange, Yellow, Green, Blue, Indigo, Violet (ROYGBIV)

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New Notes: 3.3 Technology Improves the Way People use Energy.

Warm up:

• 1. Why are LED light bulbs more energy

efficient than incandescent light bulbs?

• 2. What are ways we can make cars more

energy efficient?

• 3. What is one advantage and one

disadvantage of wind power?

• 4. What is one advantage and one

disadvantage of solar power?

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A.In many common energy conversions, most of the wasted energy is released as heat

• a. For example: only 5% of the electrical

energy put into an incandescent light blub is converted into the desired light energy. Therefore 95% of that electrical energy is wasted.

• b. Solution: LED: Light Emitting Diode
• A. Efficient Cars:
• a. Fuel Injectors: control and monitors,

how much gas goes into the engine.

• b. Hybrid Cars: Run from 2 separate

engines, gas powered and battery (electric) powered. Braking recharges the battery.

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Technology Improves the Use of Energy Resources:

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• A. Fossil Fuels are limited resources and

can have damaging effects on the environment.

• i. Examples are: petroleum, natural

gas, and coal

• ii. Due to the harmful environmental

effects and because there is a limited supply of fossil fuels scientists have discovered continue to look for alternative energy resources

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Alternative Energy Resources

• i. Solar Energy:
• 1. Solar Cells: layers of light sensitive material

that convert sunlight into electricity.

• a. Solar Cells provide electrical energy to

power satellites, calculators, cars, homes etc…..

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• 2. Solar cells are very quiet and clean but the

materials are expensive and solar cells are not very efficient at producing large amounts electrical energy.

• 3. Green houses use glass to trap solar energy

indoors so plants can grown in the winter.

• ii. Wind Energy:
• 1. The kinetic energy of the wind has been used

to move sail boats, grind grains, pump water etc…..

• 2. Today we can use the wind to produce

electricity.

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• iii. There are other forms of alternative energy that

we will be discussing and learning about in our alternative energy projects: 1.For example: Geothermal energy, hydroelectric energy (water, tides

• cean

currents), nuclear energy, clean coal technology, biomass, algae fuel, bio fuel and ethanol, hydrogen

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