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