Example of waves that go through substances
Seismic waves
Example of waves that don’t have to got through substances (medium)
Electro magnetic radiation
The bigger the ………. The more energy the wave has.
Amplitude
Frequency x wave length = ?
Wave speed
Type of wave that
- travels through solids and liquids
- has longitude waves
- is the fastest
Primary waves
Longitude waves
Type of waves that
- only travels through solid objects
- slowest wave
- transverse wave
Secondary wave
Transverse waves
What are the two ways of measuring the distance to a star?
- Parallax (only less than 400light yrs)
- Standard candles
List 3 parallax pro’s
- quite accurate
- can do it from earth
- not to expensive
List 2 parallax con’s
- have to wait 6 months
- can only measure distances smaller that 400 light yrs
What are standard candles?
Stars of fixed brightness
How do we use standard candles to find the distance to stars?
By comparing the relative brightness of other stars to standard candles we can calculate the distance
What are the pro’s (1) an con’s (3) of standard candles
Pros - can measure distances larger than 400 light yrs Cons - not as accurate - does not work with all stars - needs special equipment
How does the sun get its energy?
By nuclear fusion
What is nuclear fusion?
Nuclear fusion is when atomic nuclei join together due to the high pressure in the sun because it is so hot.
What do waves transfer?
Energy
List the three problems with Alfred Wedgner’s theory of continental drift
- no mechanism
- he was a meteorlogist
- there what’s no evidence
- already had simpler theories explaining some of his evidence
What is the mechanism for continental drift?
Radioactive decay generated in the earths core causes general convection currents in the mantle.
How often does the earths magnetic field reverse and what is the evidence of this?
Every few hundred thousand yrs ( billion). Evidence = formations of rocks and where the particles are.
What is real and relative brightness?
Used to describe light of stars.
Real brightness is it true brightness. And relative brightness is what we see depending on how close it is to earth. Real and relative brightness are used in standard candles.
How an we work out the structure of the earth using seismic waves?
By measuring the time it take for a seismic wave to travel across the earth from an earthquake. This is because seismic waves speed up and change directions when they enter denser regions. Also, p-waves are longitude and can pass through the earths core when s-waves can’t. This means the earths core must be liquid.
What are the characteristics of a longitude wave (a p-wave)?
Particles vibrate along the direction of motion of a wave 〰 🌊
🏄= surfer is a particle traveling along(itude) a wave
What is a transverse wave (s-wave)?
The particles travel at a right angle to the direction of motion of the wave
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Name 6 objects in our solar system.
Asteroids, comets, stars, planets, moons, dwarf planets
Name the 8 planets from heaviest to lightest.
Jupiter, Satern, Uranus, Neptune, Earth, Venus, Mars, Mercury
Jsunevmm
JuSt U NEVer Mind Mercury.
