Science_T4_2022

are light and sound convert-able forms of energy?

yes

light energy can be converted via;

photosynthesis, solar panels

sound energy can be converted via;

microphones

thermal energy (aka heat) is transferred via: (3 things)

conduction, convection, radiation

conduction occurs in

solids

convection occurs in

liquids and gases

radiation occurs in

anywhere! even in a vacuum

heat travels faster when:

moving particles vibrate against more, which vibrate against more, etc.

heat conduction travels at different speeds, depending on the type and state of matter. state the materials, worst to best:

gases are poor
liquids are okay
solids are fastest
within solids, metals tend to be better since they're denser

sound and light travel as ;

waves

what are the two types of waves

transverse waves, i.e. water waves), and longitudinal waves (aka compression waves), i.e. sound waves

transverse waves work via;

the medium carrying the wave oscillates UP and DOWN PERPENDICULAR to the direction of energy transfer. consists of a series of crests and troughs.

longitudinal waves work via;

the particles move PARALLEL to the propagation direction of the waves. consists of a series of COMPRESSIONS and RAREFACTIONS.

a wavelength is

the distance between two adjacent crests

amplitude is

the maximum distance that each particle moves away from its resting/equilibrium position.

amplitude DETERMINES:

loudness

a period is

the time it takes for one COMPLETE wave to pass a given point, in SECONDS

frequency is

the number of COMPLETE WAVES that pass a point in ONE second. it's measure in waves per second, or HERTZ (Hz).

frequency determines

pitch -- the higher the frequency, the closer the waves are together, and the higher the sound is.

speed is

the horizontal speed of a POINT on a wave as it propagates itself, in meters per second

sound energy is carried

as compression waves; just air particles being pushed together and spread apart

sound can't travel through

empty space

hertz are named after...

heinrich hertz, who first detected radio waves in 1887

sound waves travel faster in mediums whose particles are

closer together, and its slower when the particles are further apart

why do sound waves move faster in warm air?

the particles have more kinetic energy, so they move quicker

sounds with frequencies higher than humans can hear is called

ultrasound. an example of this is dolphins

what are two uses of ultrasound

sending a sound wave through a mother's body to get an image of the child, and sonar along the ocean floor

a cathode ray oscilloscope converts sound energy into

electrical energy, allowing it to be studied

a cathode ray oscilloscope detects sound using what:

the air pressure changes. it produces a graph called a waveform.

the dB (decibel) scale increases by powers of 10 per HOW MANY dB?

10dB. if 0dB is the quietest audible sound, 30 dB is 10^3 (1000) times louder than that, 40 will be 10^4 (10 000) times louder, etc.

any sound above WHAT dB can cause hearing loss:

above 85 dB. you know it's above this if you have to raise your voice to be heard by someone else.

filler card

filler card

epicenter

the point at the surface of the earth directly above the focus

fault

a fracture in the rocks that make up the earth's crust

focus of an earthquake

the point within the earth where an earthquake starts

seismic waves

waves that transmit the energy released by an earthquake

plates

massive rocks that make up the outer layer of earth's surface and whos movement along faults triggers earthquakes

types of plate boundaries

divergent, convergent, transform

two main categories of seismic waves:

body waves (through the body of the earth) and surface