what is the source of the suns energy?

Name a method that measures the distance to stars

What stops astronomers from observing the night sky in a city?

How old is the universe?

which is biggest out of an
a)planet b)asteroid c)comet

Is deeper rock older or younger than the rock above it?

what does the outside of the earth consist of?

what was Wegener's evidence for the theory of continental drift?

Why was Wegener's theory not accepted?

what causes seafloor spreading?

where are volcanoes and earthquakes likely to happen?

what is evidence for seafloor spreading?

what are the vibrations detected from the site of an earthquake called?

what are the layers in the earth, starting from the middle?

What can we say if the vibrations in a wave are in the same direction as the direction of travel?

what is the distance from one wave crest to the next called?

What is the unit of frequency?

What is the speed of a wave with a wavelength of 2 metres and frequency of 6 hertz?

Which type of wave can be detected on the other side of the Earth from an earthquake?