P1.4 Flashcards
What waves are sound, how is pitch affected, how is volume affected
Longitudinal, pitch affected by frequency, higher it is the high the pitch. Volume based on how tall it is, amplitude
What round of sound can we hear
20-20000Hz/20Khz
What is infrasound
Sound waves below a frequency of 20Hz
Why is infrasound used to communicate between large animals
There is usually a large distance between them and infrasound can travel much further than sound with a higher frequency. Whales can communicate 100Kms using it
How can infrasound be used with animals
Sometimes it’s hard to track animals such as giraffes as they moves several kilometres everyday and sometimes through forest where it’s hard to see them. Microphones can be used to pick up there infrasound so they can then be tracked using that
How can infrasound be used to help scientists and volcanoes
Infrasound is emitted by volcanoes when they erupt. Volcanoes are often in places far from people so it’s hard to constantly monitor them but once the infrasound is detected, scientists know it’s erupting and are then able to monitor it
What’s the difference between a meteor and meteorite
Meteors are rocks that come into the atmosphere, météorites are meteors that crash into the earth.
How can infrasound be used with meteors
They often fall over unpopulated areas so it’s hard to monitor them but they also produce infrasound which can be detected and used to track it so we can see if ‘‘tis going to hit a populated area
What is ultrasound
Sound higher than 20000Hz
How does sonar work
Ultrasound is emitted and then reflects of other surrounding objects. By detecting these reflections, an image of the surroundings can be produced
How do humans use sonar
Loudspeaker emits ultrasound and a microphone detects its reflections. Using the time it took for the reflection to return and how fast the sound was travelling, its distance can be measured
What is distance travelled formula for sound
Distance(M) = speed (m/s) * Time (s)
Why is gel used in ultrasound
To stop the ultrasound reflecting of the skin
What kind of waves are earthquakes
Seismic waves.
What is the focus of an earthquake
The place of where the earthquake came from
What is the epicentre of an earthquake
The point on the surface of the earth directly above the focus
What shape are longitudinal waves
Push pull shape, like sound waves
What shape are transverse waves
Like s shapes, light waves
What kind of waves are seismic waves
Either longitudinal or transverse
What are seismometers
Equipment that detect seismic waves
How can seismic waves be used to detect oil and gas
They are made by dropping something heavy or settting of an explosion. Seismometers then detect the travel of the waves as they are refracted and reflected through the different types of rock. The information can be used to see what kind of rock I’d there by determining its density
How can earthquake epicentres be found
The time between the first p waves and first S waves arriving can be used to messer the distance it is from the seismometer . Data from three or more seismometers can be used to triangulate the location of the earthquake
How care tectonic plates moved
Convection currants in the earths mantle move the plates
How are convection currants in the mantle caused
Magma heats up nearer the core and rises as it’s hotter. As it rises, it cools and begins falling down, this changing in direction causes it to move in a direction parallel to the tectonic plates and moves them
What causes earthquakes
When the friction between tectonic plates breaks, causing the plates to jerk
Why is it hard to predict when an earthquake will happen
It’s hard to measure the forces between plates so it’s hard to know when they will break and jerk
