Behavior+of+Fluids

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[|Help with Pressure]

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[|Try some Calculations]

 **Plug in these examples:** the **force** is the weight of the block placed on a table: **80 N** The **area** of the force is the base area of the block: **2 square metres**

What is the pressure on the table?

**Fun Fact:**  Camels need to be able to walk around on sand without sinking into it.  This means that they need to reduce their **pressure** on the ground.  Large feet mean a large area of contact, and thus less pressure.

The Pressure of air is known as  media type="youtube" key="av_kaGtH9GU?fs=1" height="385" width="640" align="center"

Air Pressure on Flame  media type="youtube" key="TX2YZZbnx4s" height="344" width="425" media type="youtube" key="LYcPvm-QhSE" height="344" width="425"

 Air Pressure in Straw

 We don't feel the air pressure because our body fluids push back!



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Example: Your ears popping in an airplane [|What causes your ears to pop?]



When volume decreases, pressure increases

**When temperature increases, pressure increases **  ** (though volume does not increase) **

<span style="color: #800000; display: block; font-family: 'Courier New',Courier,monospace; text-align: center;"> **<span style="color: #0000ff; display: block; font-family: 'Courier New',Courier,monospace; font-size: 130%; text-align: center;">The opposite is true, too. When temperature decreases, pressure decreases **

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<span style="color: #0000ff; display: block; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif; font-size: 120%; text-align: center;">Water pressure also increases the deeper you go under water.

<span style="color: #000080; display: block; font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 130%; text-align: center;">The pressure pushing up on an object is stronger than the pressure pushing down. <span style="color: #000080; display: block; font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 130%; text-align: center;"> This is because the bottom of the object is deeper than the top of the object.

<span style="color: #000080; display: block; font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 130%; text-align: center;"> The upward force is called the <span style="color: #000080; display: block; font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 130%; text-align: center;"> **<span style="color: #0ca1a1; font-family: 'Lucida Console',Monaco,monospace;">The idea of buoyancy was summed up by Archimedes, a Greek mathematician, ** **<span style="color: #0ca1a1; font-family: 'Lucida Console',Monaco,monospace;"> in what is known as Archimedes Principle: ** **<span style="color: #0ca1a1; font-family: 'Lucida Console',Monaco,monospace;"> //Any object, wholly or partly immersed in a fluid,// ** **<span style="color: #0ca1a1; font-family: 'Lucida Console',Monaco,monospace;"> //is buoyed up by a force equal to the weight of the fluid displaced by the object.// ** <span style="color: #000080; display: block; font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 130%; text-align: center;">

<span style="display: block; font-family: 'Comic Sans MS',cursive; font-size: 110%; text-align: center;"> Use the information below to answer the following questions: <span style="display: block; font-family: 'Comic Sans MS',cursive; font-size: 110%; text-align: center;"> What is the density of each object? <span style="display: block; font-family: 'Comic Sans MS',cursive; font-size: 110%; text-align: center;"> If all are put in a container, which will float on top, which will be in the middle, and which will sink? <span style="display: block; font-family: 'Comic Sans MS',cursive; font-size: 110%; text-align: center;">Liquid A: Mass=40g and Volume=10mL <span style="display: block; font-family: 'Comic Sans MS',cursive; font-size: 110%; text-align: center;"> Liquid B: Mass=25g and Volume=10mL <span style="display: block; font-family: 'Comic Sans MS',cursive; font-size: 110%; text-align: center;">Object C: Mass=18g and Volume=6mL <span style="color: #000080; display: block; font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 130%; text-align: center;">media type="youtube" key="VDSYXmvjg6M" height="344" width="425"media type="youtube" key="43KmpQGgXHI" height="344" width="425"

<span style="color: #000080; display: block; font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 130%; text-align: center;"> What happens when you squeeze a plastic bottle filled with water? <span style="color: #000080; display: block; font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 130%; text-align: center;"> If closed, the water has no where to go and the pressure is the same all in the bottle <span style="color: #000080; display: block; font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 130%; text-align: center;"> not just where you squeezed it. This is known as __**Pascal's Principle**__. <span style="color: #000080; display: block; font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 130%; text-align: center;">==================================================

Questions to check your understanding
<span style="color: #000080; display: block; font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 130%; text-align: center;"> 1. What is the pressure on 2 square meter surface where you push with a force of 6 Newtons?

<span style="color: #000080; display: block; font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 130%; text-align: center;"> 2. What pressure is created when 5.0 N of force are applied to an area of 2 square meters?

<span style="color: #000080; display: block; font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 130%; text-align: center;"> 3. How does the pressure change if the force is increased to 10.0 N? (from ques. 2)

<span style="color: #000080; display: block; font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 130%; text-align: center;"> 4. A sample of 10.00g of oxygen has a volume of 6702 mL. The sample weight of carbon dioxide is the same as that of the oxygen but it occupies 5058 mL. What is the density of each gas?

<span style="color: #000080; display: block; font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 130%; text-align: center;"> 5. The density of methanol at 20oC is 0.791g/mL. What is the mass, in g, of a 280 mL sample?