Physics Flashcards
travelling sounds and types of sounds (23 cards)
travelling sounds
All sounds require a medium (ie, particles) to travel through, therefore sounds cannot pass through a vacuum (such as space).
So, do sounds travel faster in solids, liquids or gases?
The closer the particles are to each other, the faster the sound will travel. Therefore sounds travel fastest in solids, then in liquids.
wave energy
Waves are a means of transfer-ring energy – this is done in a repeating cycle. The particles vibrate, or
oscillate, back and forth.
names one or two types of wave
two types of wave:
- transverse
- longitudinal
whats happens in a transverse wave?
In a transverse wave, the vibrations occur at right angles to the direction of energy transfer.
what happens in a longitudinal wave?
In a longitudinal wave, the vibrations occur in the same direction as the direction of energy transfer.
frequency
All types of wave have a frequency. This is a measure of how many waves pass a particular point every second.The unit for frequency is the hertz (Hz)
superposition
The principle of superposition shows what happens when two waves meet after approaching each other.
whats is constructive interference?
Constructive interference occurs when two waves travelling in
opposite directions reinforce each other.
what is destructive interference
occurs when a peak and a trough travelling in opposite directions partially or fully
cancel each other out
what does a loudspeaker do?
A loudspeaker has a cone that vibrates with the same frequency as the sound being played. An electrical signal passing through an electromagnet causes the
vibration, which agitates air particles, creating a sound wave.
what does a microphone do?
A microphone has a small diaphragm that vibrates when a sound wave (moving air from our voice) hits it. This generates a small electrical signal, which passes into an amplifier – this makes the sound louder when
it is played through the loudspeaker.
how is it related into making music
Each voice and instrument has its own unique series of tones that give the waves have distinct shapes.
This is partly because the sound wave is made in different ways…
How much hertz can we hear?
We are not able to hear sounds below 20Hz (subsonic), or sounds above 20000Hz (ultrasonic).
hearing damage
The loudness of a sound can be measured in decibels (dB).
The louder the sound, and the longer you are exposed to a loud sound, the greater the chance of hearing damage.This could include damage to the eardrum, bones or the hairs in the cochlea, which may not be repaired.
thermal equilibrium
Thermal energy always transfers from where there is more, to where there is less.
what is heat?
Heat is a type of energy (normally referred to as thermal energy).
what is temperature
Temperature is a measure of how intense the heat is (‘hotness’), and can be measured using a thermometer; the unit is
degrees Celsius (°C).
what happens in thermal conduction?
When the particles nearest the heat source gain energy, and they vibrate more…
conduction
Conduction cannot occur in liquids or gases, since the particles are too far apart to transfer energy by collision.
convection
Convection is the method of heat transfer in liquids and gases (but not solids), as the particles are able to move and flow past each other.
convection currents
The heated particles can then displace the cooler particles at the top of the container.
infrared radiation
All objects emit waves of infrared energy (a bit like light, but we can’t see it); this process is known as radiation.
