Pressure and Buoyancy quiz

More questions about Pressure and Buoyancy

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1. 1 Easy

   Why does ice float on water?

   Answer: Expansion on freezing

   Why: Even perfectly clear ice with no bubbles floats, because frozen water itself is about 8% less dense than liquid water.

2. 2 Medium

   Why does a drink rise up a straw?

   Answer: Air pressure

   Why: Since the air outside does the pushing, even a perfect vacuum in the mouth could raise water no more than about 10 meters up a straw.

3. 3 Hard

   What ocean depth on Earth matches Venus's surface air pressure?

   Answer: About 900 m

   Why: Venus's thick carbon dioxide atmosphere presses down with about 93 bar, roughly 93 times the air pressure at sea level on Earth.

4. 4 Easy

   Why does a can of regular cola sink when diet cola floats?

   Answer: Dissolved sugar

   Why: A 330 ml can of regular Coca-Cola holds 35 g of dissolved sugar, while diet cola gets its sweetness from a fraction of a gram of sweetener.

5. 5 Medium

   Whose principle makes a hydraulic car lift work?

   Answer: Blaise Pascal

   Why: A piston with 50 times the area pushes 50 times harder, but it moves only a fiftieth as far as the small one, so no energy is created.

6. 6 Hard

   Below which height lies half the mass of Earth's air?

   Answer: About 5.5 km

   Why: Air thins so quickly with height that 99% of the atmosphere's mass lies below just 30 km.