- Created by: leah murray
- Created on: 08-06-10 20:44
rocks and plate tectonics
Rocks provide evidence for changes in the universe by preserving sediments and fossils in layers.
There are 3 ways that mountains can be formed at the edge of plates:
Where an ocean plate dives back into the earth, volcanic peaks may be formed at the surface,
The pushing movement at destructive margins can also cause rocks to buckle and fold, forming a mountain chain,
Sometimes an ocean closes completely, and two continents collide in slow motion. the edges of the continents crumple together and pile up, making mountain chains. This is happening today in the Himalayas and Tibet.
The earth must be older than it's oldest rocks which are 3900 million years old.
rocks and plate tectonics continued
Evidence for continental drift and tectonic plates are "zebra stripes" at the bottom of the ocean, mountain ranges, volcanoes, earthquakes and tsunamis.
Earthquakes,volcanoes, and mountain building generally occur at the edge of tectonic plates.
To prepare people for natural disasters public authorities can:
Educate people so that they know what to do,
Organise public drills,
Enforce building regulations that reduce the chance of buildings collapsing,
Prepare emergency plans and ensure that trained staff can respond quickly.
the solar system and space
In our solar system there's planets, asteroids, comets, meteors and stars.
the fusiion of hydrogen nuclei is the source of the sun's energy.
If a massive asteroid collides with the earth, the dust from the collision could rise up into the earth's atmosphere and block out the sun, this could cause plants to die and in further effect animals to die.
Light travels at a very high speed.
Distant objects in the universe are observed as younger than they are now (the light that is reaching us now is from thousands of years ago).
The sun is a star in the milky way galaxy.
All chemical elements with more mass than helium where made in earlier stars.
the solar system and space continued
Distant galaxies are moving away from us, this is summed up in Hubble's law.
The universe began with a "big bang" about 14 000 million years ago.