science experttsss PLEASE help?

Question

I'm doing a study guide for my exams coming up...so thing is i need the answers to these questions [[DUH]] and i would really appreciate it if instead of saying look it up yourself...or youre slow thats easy....or learn how to spell [[its called computer language]] or u no shizz like that just help me out here

thnxx

QUESTIONS:
a] describe archimedes principle of bouyancy
b] esplain why density of a substance is always constant
c] how is pressure affected by elevation above sea level? depth below sea level?

Answer 1

Here you go ...

a) The idea of buoyancy was summed up by Archimedes, a Greek mathematician, in what is known as Archimedes Principle: Any object, wholly or partly immersed in a fluid, is buoyed up by a force equal to the weight of the fluid displaced by the object.

b) DENSITY is a physical property of matter, as each element and compound has a unique density associated with it. Density defined in a qualitative manner as the measure of the relative "heaviness" of objects with a constant volume.

For example: A rock is obviously more dense than a crumpled piece of paper of the same size.
A styrofoam cup is less dense than a ceramic cup.

Density may also refer to how closely "packed" or "crowded" the material appears to be - again refer to the styrofoam vs. ceramic cup.

c) Low pressure areas have less atmospheric mass above their location, whereas high pressure areas have more atmospheric mass above their location. Similarly, as elevation increases there is less overlying atmospheric mass, so that pressure decreases with increasing elevation. As elevation increases, the number of molecules decreases and the weight of air therefore is less, meaning a decrease in air pressure. In fact, while the atmosphere extends more than 15 miles (24 km).

I hope this helps.