Ch. 12 Lessons 1, 2, 3, 5

Light rays bouncing off a surface at random angles is called_________.

Scattering

Objects that do not allow light to pass through cause_________.

Shadows

The wavelength of a wave times its frequency is the_________of the wave.

Speed

If some light goes through, the object is_______.

Translucent

If most light goes through an object, the object is__________.

Transparent

The Earth is a giant permanent _____.

magnet

Whenever an electric charge moves, it creates _____ forces.

magnetic

When a magnet is cut in half, each of the two pieces has a _____ pole and a _____ pole.

north, south

To make a sound louder, you need to use more energy, which increases the amount of ________________________________________ displaced.

particles

The higher the frequency of pitch of a sound wave, the more ________________________________ pass in a period of time.

peaks

To increase the pitch of a musical instrument, you need to ________________________________ the part that vibrates.

shorten

Sound travels faster through a _________________________________ than it travels through a liquid or a _______________________________________.

solid / gas

Sound navigation and ranging, or _________________________________, is used to find the depth of a body of water and locate objects beneath water.

sonar

A series of compressions and rarefactions moving through a medium is a ____________________________.

sound wave

Heat continues to flow from one object to another object until both have the same __________________________________.

temperature

Light waves vibrate in directions ___________ to the direction of their motion.

Perpendicular

A 30 dB noise has _________________________________ more energy than a 10 dB noise, but a 30 dB noise sounds about ________________________________________ as loud as a 10 dB noise.

100 times / four times

Why is the pitch of a train's whistle higher as the train approaches and lower as it moves away?

As the train moves toward you, you will hear the peaks of the sound wave quicker than if the train were standing still. As the train moves away from you, the peaks of the sound wave arrive at your ear more slowly and the pitch is lower.

If you move in the direction from which a sound wave is coming, you hear a higher pitch as a result if the ______________________________ effect.

Doppler

Light is vibrating __________ and _____ energy.

Electric, Magnetic

Describe how heat is used in a kitchen. What appliances produce heat, and how do they produce it? What objects are used as insulators, and what objects are used as conductors?

Heat is transferred by conduction, convection, and radiation. A frying pan uses conduction to transfer heat directly from the stove, to the pan, to the eggs. Boiling water is heated by convection as the hotter water rises and the colder water falls. A toaster uses radiation to send electromagnetic rays from the hot wires to the toast. Metal is a good conductor of heat, and wood or plastic are insulators.

You can increase the strength of an electromagnet in three ways: ___________, place an iron rod inside the coils, or ___________.

Increase the current, add more coils

If no light goes through, the object is_______.

Opaque

Light travels fastest in a __________.

Vacuum

Light has properties of both ______ and ______.

Waves, particles

When sound hits soft, thick, or uneven materials, much of the sound is _____________________________; when sound hits flat, firm surfaces, much of it is ______________________________.

absorbed / reflected

Heat traveling by conduction moves at the speed of which molecules can ______________________ one another and change how fast nearby molecules are vibrating.

bump

Heat energy caused by friction is usually a waste product that results when energy ____________________________ or ______________________________.

changes form / performs work

A magnetic field _____ around a straight wire when current is flowing through it.

circles

The _____ together the lines of a magnetic field, the stronger the magnetic force.

closer

Regions of a material that have many molecules squeezed together are ____________________________; regions that have fewer molecules spread apart are _________________________________.

compressions / rarefactions

As hot and cool portions of liquids or gas move, _______________________________ currents form.

convection

Volume is measured in ____________________________________.

decibels

Amplitude of sound depends on how _______________________________ the air in compressions is compared to normal air.

dense

Thermal conductivity increases as ______________________________ increases, so ___________________________________ are the best conductors of heat and _________________________________ are the worst conductors.

density / solids / gases

The volume of a sound decreases with _______________________________________ because the same amount of sound energy is spread over a larger and larger area.

distance

An electric current that produces a magnetic field is a called a _____

electromagnet

Convection currents move heat more slowly than do ________________________________ but more quickly than conduction.

electromagnetic rays

Heat is energy that moves from an object with a(n) ____________________________ temperature to an object with a(n) ______________________________ temperature.

higher / lower

Wrapping many loops of wire together _____ the magnetism of the coil.

increases

The heat you can feel radiating away from hot objects as electromagnetic rays is called ____________________________ rays.

infrared

Objects with a low heat capacity change temperature _____________________________ when heated and give off _________________________________ as they cool.

quickly / heat

Like poles of a magnet _____ each other, and unlike poles _____ each other.

repel, attract

Bats make sound and listen to the _________________________________ to locate prey.

returning echo

Sound waves vibrate the medium in the ________________________________ direction that the energy moves.

same

A material that conducts heat poorly is a good ______________________________.

thermal insulator

Heat is the ________________________ amount of thermal energy that an object releases.

total

Conduction can occur between objects that are _________________________________.

touching

Sound cannot travel through a _____________________________, which is a region of space that contains no matter.

vacuum