p5 waves

Question 1

what is a wave

Answer 1

a wave is an oscillation that transfers energy

Question 2

what is a mechanical wave

Answer 2

this is a wave that requires a medium to travel through, eg sound waves

Question 3

what are the two types of wave

Answer 3

longitudinal eg sound.

transverse waves eg the wave made on a string

Question 4

whats the difference between transverse and longitudinal waves

Answer 4

longitudinal = the singular atoms vibrate parallel to the direction of energy transfer.
transverse = the individual atoms vibrate perpendicular to the direction of the energy transfer.

Question 5

what is the amplitude of a wave

Answer 5

the distance between the middle and the crest or trough. measured in metres or volts

Question 6

what is the wavelength

Answer 6

the distant from one point on a wave to the same point on the next wave, measured in metres

Question 7

what is frequency

Answer 7

the number of waves per second, measured in hertz

Question 8

what is the time period

Answer 8

the time it takes for a wave to pass a point. measured in seconds.

Question 9

what are the two ways to represent a wave.

Answer 9

time trace and and a snap shot. in a time trace it shows the displacement of the wave varies with time. a snapshot shows how displacement of the waves varies with distance.

Question 10

whats the difference between snap shot and time trace of a wave.

Answer 10

on a time trace you can measure the period from one wave to the next.
on a snapshot you can measure the wave length

Question 11

how can you model transverse waves

Answer 11

put a cork on some water and make small ripples.you will notice that the cork goes up and down but doesn’t follow the wave

Question 12

how do you calculate wave velocity

Answer 12

Velocity = Wavelength X Frequency
m/s = m X hz

Question 13

how to find the velocity of ripples

Answer 13

use a ripple tank, you then have to find wavelength. do this with a ruler beneath the tank and take a photo. the measure the shadow. you can calculate the frequency by looking at the number of rotations on the motor. then just use the equation

Question 14

how do the velocity of sound

Answer 14

use an oscilloscope. connect two microphones that are a certain distance apart. this machine measures the time it takes sound to travel from one microphone to another

Question 15

why the speed of sound vary in different temperatures

Answer 15

because sound is a mechanical wave it travels by physically hitting other atoms. in warm temperatures this is more likely to happen.

Question 16

what is refraction

Answer 16

this is when a wave changes velocity and therefor direction

Question 17

what happens when a wave slows down / speeds up

Answer 17

slows down - bends towards the normal

speeds up - bends away from the normal

Question 18

what is the normal

Answer 18

the line at 90 degrees to the surface

Question 19

when the velocity increases what happens to wavelength and frequency

Answer 19

wavelength - increases

frequency - decreases

Question 20

what three things can happen to sound at a boundary

Answer 20

reflects (an echo)
transmitted and possibly refracted
absorbed

Question 21

what is ultrasound and what is it used for

Answer 21

this is sound with a frequency over 20,000 hz. humans cannot hear it. it can be used for medical imaging (babies and kidney stones)
also used for navigation in ships

Question 22

how does the ear detect sound

Answer 22

sound waves are directed to the ear drum which vibrates. these vibrations are passed on and amplified by ossicles. it travels through the oval window. it then reaches the cochlea which contains a liquid that passes the vibrations on to small hairs. these small hairs are attached to sound detecting cells. chemical signals are sent to the brain which interprets it as sound.

Question 23

what is natural frequency

Answer 23

the frequency in which an object vibrates easily

Question 24

what is resonance

Answer 24

this is what happens when an object is vibrated at its natural frequency. it vibrates more violently

Question 25

why do humans hear a range of frequencies

Answer 25

because within the ear are hairs that vibrate at different frequencies. the range of frequencies that we hear depend on the range of sizes of the hairs