P1H

- Shock waves from earthquakes can be deteceted by seismometers and recorded on a seismograph.

- Shockwaves from earthquakes can cause damage to buildings and the Earth's surface and tsunamis.

- P waves are longitudinal.

- P wave travel through both solids and liquids.

- S waves are transverse.

- S waves only travel through solids.

- P waves travel faster than S waves.

- Exposure to UV radiation can cause: suntan, sunburn and skin cancer.

- SPF means Sun Protection Factor.

- Darker skins have lower cancer risk as they absorb more ultraviolet radiation so less UV reaches the underlying tissues.

- The ozone layer protects the Earth from ultraviolet radiation.

- The ozone layer has been depleted by environmental pollution from CFCs.

- When there's an earthquake, it produces shock waves which travel through the Earth. We record these seismic waves all over the surface of the planet using seismographs.

- Studies led scientists to confirm that CFCs were causingt he depletion of the ozone layer so the international community banned them. 

- Now international bans and restrictions on CFC use have been put in place because of their environmental impact.