4.29. Pressure in Fluids http://www.ck12.org
FIGURE 4.56
Summary
- All fluids exert pressure because their particles are constantly moving and bumping into things.
- Pressure is defined as the amount of force acting on a given area. It measures how concentrated a force is.
- The SI unit for pressure is the Pascal (Pa), or N/m^2.
- To calculate pressure, divide force in Newtons (N) by area in square meters (m^2 ).
Vocabulary
- fluid: Substance that can flow and take the shape of its container; either liquid or gas.
- Pascal (Pa): SI unit for pressure, equal to 1 Newton per square meter (N/m^2 ).
- pressure: Result of force acting on a given area.
Explore More
At the following URL, watch the demonstration showing how a siphon works. Then answer the questions below.
http://www.youtube.com/watch?v=CZmP0vsRBZ8
MEDIA
Click image to the left for use the URL below.
URL: http://www.ck12.org/flx/render/embeddedobject/82425- Why does the liquid move into the siphon when air is removed from the siphon by the pipette?
- How does the liquid flow uphill out of the upper cup?
- Why doesn’t the liquid in the siphon flow back down into the upper cup as well as down into the lower cup?
Review
- Why do fluids exert pressure?
- Explain how a pushpin concentrates the force you apply to it.
- What is the SI unit for pressure?
- A large box weighing 700 N is resting on the ground on an area of 1 m^2. How much pressure is the box
exerting on the ground? - What factors influence fluid pressure?