Stable Earth

What is used to show the different types of earthquake wave?

What do L waves do?

What are P waves?

State two features of P waves.

What are S waves?

State two features of S waves.

What happens to P waves as they travel through the Earth?

What means that scientists can work out the size of the Earth's core?

Which type of wave are not detected on the opposite side of Earth to an earthquake?

Why are S waves not detected on the opposite side of Earth to an earthquake?

What does this tell scientists?

What is a tan caused by?

What is the name of the pigment produced by cells in the skin that produces a tan?

Why do people with darker skin not tan as easily?

What can be used to reduce the risks of staying out in the Sun?

Write the word equation for maximum length of time to spend in the sun.

Fill the gaps:
People are becoming more ..... of the dangers of ......... to ultraviolet radiation, including the use of ... beds.

What did scientists not believe at first?

Why did they think this?

Who confirmed the results and increased confidence in the findings?

Where is the ozone found?

What does the ozone help to do?

Which type of gases destroy the ozone and reduce the thickness of the ozone?

What does this do?

Why is the ozone layer at its thinnest above the South Pole?

What do scientists use to monitor the thickness of the ozone layer?

True or False?
There is international agreement to reduce CFC emissions.