Practice7-Q6
As geologists, one of our major areas of concern is rocks. The best way to define a rock is as matter composed of one or more naturally occurring substances. They can be anything from a tiny grain of one mineral to a massive compound made up of a large mix of minerals. There are two kinds of rock that I want to discuss today.
The first is igneous. These rocks start off as hot, liquid matter and cool to form what are commonly called fire rocks, or to us geologists, igneous rocks. Obsidian, that’s obsidian, represents this class well. It is a beautiful rock that forms when the lava from a volcano cools so rapidly that it does not allow any minerals within it to crystallize. Because no crystallization occurs, this rock takes on several unique properties: it often looks like beautiful black glass and can be chiseled or cut into sharp points, which is why it was often used as an implement for war in ancient societies.
The second is sedimentary. These rocks come from either the Earth’s surface or its oceans and seas. One great example is Halite. Seawater contains a high concentration of salt and halite is made when a body of seawater undergoes large amounts of evaporation. You see; as the water evaporates, the seawater can no longer hold as much salt as it once did. This salt then begins to fall out of solution as small salt rocks called Halite. If you cut these rocks in half, you won’t find a smooth surface; instead, you’ll find a mixture of separate pieces of rock that create a stratified or broken look, a common characteristic of sedimentary rocks.
Post dates | Users | rates | Contents |
---|---|---|---|
2016-03-11 | saramhl | 80.00 | Check this speaking |
- Jean Piaget, a famous Swiss psychologist, proposed a theory to explain how children learn to adapt their thinking to better understand and function within their world. According to Piaget, they adapt their thinking in two important, but different ways: th 90
- practice test 10-q4 90
- Adaptive Reuse Over time many buildings become old run down and outdated They outlive their original purposes and become a burden for their communities Rather than spend a large amount of money to tear down these buildings and construct newer more useful 45
- PRACTICE5-Q5 90
- 21. Some people enjoy change, and they look forward to new experiences. Others like their lives to stay the same, and they do not change their usual habits. Compare these two approaches to life. Which approach do you prefer? Explain why. 80
24 in 30
Only need to pick up the main features.