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Liquid and Atmospheric Pressure. Physics February 15/16. Make a prediction. If I put 3 holes in the bottle, one right on top of the other, which will the water flow the fastest?. C. B. A. Answer.
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Liquid and Atmospheric Pressure Physics February 15/16
Make a prediction • If I put 3 holes in the bottle, one right on top of the other, which will the water flow the fastest? C B A
Answer • If I put 3 holes in the bottle, one right on top of the other, which will the water flow the fastest? The bottom hole WHY? The pressure of a liquid depends on the depth of the liquid
Pressure and Depth Examples • Figure 19.2 • Figure 19.3 • Figure 19.4 • Hands-up, hands-down
What else affects liquid Pressure? • The density of the material • More dense liquid have more pressure!!! • For example: • Oil vs. Water
Check for Understanding • Both are filled with water, which has more pressure. • One is water and the other is alcohol. Which has more pressure? Why? B A WATER ALCOHOL
What about Atmospheric Pressure? • Same as liquid • Density • Depth • Speed of air/fluid also matters
Speed of air/fluid also matters • When speed increases then pressure drops • Bernoulli’s principle • Teacher Demo/Examples • Soda can • Paper • Straw
Check for understanding When taking a shower, sometimes the curtain blows toward you. Why? • Hot water speeds up molecules in shower. • Pressure decreases inside shower (Bernoulli’s principle) • Pressure from outside shower pushes curtain
Class work • Skim sections 19.1, 20.2, and 20.7 • Answer questions: • Page 286 # 2, 4 • Page 303 #3 and 14
Closing • What factors affect the pressure of a fluid (liquid/gas)? Explain how