P1h: Stable Earth Flashcards
Describe the 2 types of seismic waves
longitudinal P waves which travel through both solids and liquids and travel faster than S waves
transverse S waves which travel through solids but not through liquids and travel slower than P wave
How can data on seismic waves transmitted through the Earth be used to provide evidence for its structure?(2)
P waves travel through solid and liquid rock (i.e. all layers of the Earth) and are detected in all parts of the Earth
S waves cannot travel through liquid rock (i.e. the outer core) so are not detected in certain parts of the Earth
How are the seismic waves detected?
detected by seismometers placed around the Earth
How does darker skin help against UV exposure? (4)
absorbs more UV radiation
less UV radiation reaches underlying body tissues
protects sensitive cells underneath
reduces cancer risk
SPF(sun protection factor) X means…
you can spend X times as long in the Sun w/o burning
What has the government done and why
spends millions of pounds per year to inform people about the risks of too much exposure to UV, including the use of sun beds, in order to improve public health
How does the ozone layer protect the Earth from UV radiation?
thick layer of ozone gas around the entire Earth which prevents UV radiation from reaching the surface by absorbing it and filtering it out
Some scientists did not believe the discovery of the hole. What was done? (4)
scientists verified their measurements of ozone reduction
measurements repeated with new equipment
measurements repeated by different scientists
predictions tested based on the explanation
How has the discovery of the hole in the ozone layer changed the behaviour of society?(2)
several countries have worked together to address the problem through international collaboration and creating new laws
use of CFCs banned in Montreal Protocol 1987
