Chapter 14Forms of Energy

What is Sound Energy? is a wave of vibrations that spreads from its source.

As sound travels through a material, the molecules that make it up in a kind of pattern.

They get closer together and then farther apart.

- the number of crests that pass by a point each second and also a measure of how fast particles are vibrating.

Sound

vibrate

Frequency

The greater the frequency the the pitch of the sound.

More vibrating causes sounds.

Sounds loudness is measured in .

Ex. On a guitar strings that are produce lower notes.

Also strings that are more tightly stretched produce notes.

higher

louder

deciblesthicker

higherhttp://studyjams.scholastic.com/studyjams/jams/science/energy-light-sound/sound.htm

Your VoiceYour vocal cords when you talk.

Vibrations are caused by air rushing past the vocal cords.

Your vocal cords make the particles in the air around them vibrate.

The vibrations travel outward through the air as sound .

vibrate

waves

Review

1) What is frequency?

2) The greater the frequency the higher the of the sound.

3) What is sound measured in?

4) When we talk what is vibrating to produce sound?

How does sound behave?

Sound travel through solids, liquids, and gases. But cannot travel through a vacuum - which is empty space with no particles.

3 things can happen with sound waves. 1) back 2) can be . 3) can pass into the second material

http://m.youtube.com/watch?v=_ovMh2A3P5k

can

bounceabsorbed

Speed at which sound waves travel is different in different materials.

Ocean = 1500 mps

Air 0 degrees Celsius = 330 mps

Echo - of sound off a wall or cliff. reflection

Sound Transfers Energy

In a sound proof room sound bounces around and inside the sound proofing material many times.

Each time it bounces the material vibrates and some energy is turned into energy.

This material absorbs nearly all the sound waves that strike it. Causes the sound to be .

thermal

muffled

For a sound to be heard, energy must first cause an object to .

For you to hear a sound your eardrum absorbs some of the energy and begins to vibrate.

The energy of the original material's vibrations passes to you.

http://www.shockwave-sound.com/sound-effects/ocean_sounds.php

vibrate

http://studyjams.scholastic.com/studyjams/jams/science/human-body/hearing.htm

Review1) What can sound not travel through?

2) List 3 things that can happen with sound waves.

3) What is a reflection of sound off a wall or cliff?

4) For sound to be produced what has to happen?

electromagnetic radiation (noun)

a combination of electrical and magnetic energy.

Comes to Earth from the Sun.

Radio waves x-rays, microwave, ultraviolet light, radiation.

The electromagnetic radiation has wavelengths that are shorter than those of visible light.

What is Light Energy?

light is a portion of the electromagnetic spectrum.

It can travel in lines, can reflect off objects, and can bend as it passes around and through them.

Different wavelengths of light have different .

Visible

straight

colors http://studyjams.scholastic.com/studyjams/jams/science/energy-light-sound/light.htm

Light is different than sound in many ways. 1) Unlike sound light is not a of particles. 2) light energy is given off by electrons. 3) Light travel through space.

Electromagnetic radiation comes to Earth from the Sun.

The spectrum or range, includes waves with many frequencies and wavelengths.

For you to see an object, it must off or reflect wavelengths of visible light. Then it must enter your .

vibration

can

give

eyes http://studyjams.scholastic.com/studyjams/jams/science/human-body/seeing.htm

Wavelengths and Energy Most sources that give off visible light also

give off heat in infrared waves. ex. Lava, light bulbs, and candles.

Stars, including the Sun, give off of the light in the universe.

In addition to visible light, the Sun gives off ultraviolet, infrared, X-ray, and other .

Stars give off diff. kinds of radiation. Some give off a little visible light and all stars give off waves.

most

radiation

How Does Light Move?Light travels fastest in a vacuum 300,000,000 meters

per second.

We usually see light moving in lines. Even if it reflects off an object, such as a mirror, light moves in a straight line, but changes .

Light bends, or , whenever it enters a new material at an angle. Ex. prism

A prism is a object that separates light into its different wavelengths.

White light comes out into its .

http://m.youtube.com/watch?feature=related&v=gtgBHsSzCPE#/watch?feature=related&v=gtgBHsSzCPE

straight

directionrefract

stransparent

colors

http://studyjams.scholastic.com/studyjams/jams/science/energy-light-sound/light-absorb-reflect-refract.htm

Objects in the path of light casts a and blocks the path of light.

A shadow is larger when the object is to the light source.

When light is absorbed, the light energy changes to thermal energy.

Convex lens - thicker in the middle. Bends light rays to make objects look . Magnifying glass.

lens - thinner in the middle than the edges. Bend light rays to make objects look smaller.

shadow

closer

larger

Concave

Transparent - easy to see through . Synonym - crystal clear

- not allowing light to pass through. Synonym - cloudy, dark

- Permitting light to pass through, but diffusing it so that persons, objects on the other side are not clearly visible. Frosted window glass is translucent, but not transparent.

clear

Opaque

Translucent

Transparent

Opaque

Translucent

Review1) How does light travel?

2) If light is given off, what else might also be given off?

3) Is a prism transparent, translucent, or opaque?

4) An object in the path of light will create what?

5) Convex lenses make things look bigger/smaller.

6) Define translucent, transparent, and opaque.

Conduction

the transfer of heat between objects that are in contact.

The heat from the stove warms the pan by conduction.

Convection

another way that heat is transferred.

Convection is the transfer of heat by a moving liquid or gas.

Thermal Energy

The total of all the kinetic and potential energy of the atoms in an object.

The thermal energy increases as kinetic energy increases.

What is Thermal Energy?

As kinetic energy increases, the object gets .

flows from a warmer object to a cooler one.

Thermal energy is the total of all the kinetic and energy of the atoms in an object.

warmer

Heat

Phase ChangesMost matter exists as a solid, a liquid, or a gas.

A change in energy can lead to a change in phase.

If the thermal energy of a solid increases enough it melts into a .

Liquid state of a substance has a higher thermal energy than its state.

If liquid gains thermal energy it can become a gas.

thermal

liquid

solid

Thermal Energy and Temperature

is a measure of thermal energy.

Temp. of an object is related to the average kinetic energy of all its particles.

People measure temperature with thermometers.

Temperature

Conduction, Convection, RadiationThermal energy naturally flows from warmer substances to cooler ones.

Thermal energy - heat Conduction - the temperature of the warmer object decrease as heat flows from it. The temperature of the cooler one rises as heat flows to it.

http://studyjams.scholastic.com/studyjams/jams/science/energy-light-sound/heat.htm

The heat flows until the objects have the same .

1) - flow of heat between objects that are touching. ex. Pan on an oven.

2) Convection - the movement of warm liquids or gasses to cooler areas. Cool water sinking as warm water rises. Convection current.

3) - the movement of energy by electromagnetic waves. Ex. Sun warming a greenhouse.

temperature

Conduction

Radiation

Review1) Heat flows from to cooler objects.

2) If thermal energy increases enough a solid can change into a .

3) What is the measure of thermal energy?

4) Heat flows until what happens?

5) What is the flow of heat between two objects that are touching called?