Viscosity & Flow Rate
What is viscosity?
The resistance of a fluid to flow.
Solve: A wooden cube has a mass of 100 grams and a volume of 50 cm³. What is the density of the cube? What is the formula for density? Include Units.
Density = mass/volume
Density 2 g/cm³
Which is more compressible: liquids or gases? Why?
Gases because there is more space in-between particles.
Solve: A box weighing 50 N is resting on a surface with an area of 10 m². What is the pressure exerted by the box on the surface? What is the formula for pressure? Include Units.
Pressure = Force/Area (P = F/A).
Pressure = 5 Pa
Name a fluid-based technology used in hospitals.
IV fluids, blood transfusion systems.
Name one liquid with high viscosity and one with low viscosity.
Honey (high) & water (low).
Why do objects float in water?
If their density is less than the density of water.
Why can gases be compressed but liquids cannot as easily?
Gas particles are farther apart, allowing compression.
Why do flat shoes create less pressure than high heels?
Flat shoes have a larger surface area, distributing force over a bigger area.
What fluid property allows ketchup bottles to work efficiently?
Viscosity.
How does temperature affect viscosity?
Higher temperatures decrease viscosity in liquids, making them flow faster.
What happens to the density of saltwater when you add more salt?
It increases.
What happens when you push a plunger in a syringe filled with air?
The air compresses and takes up less space.
Why do divers feel more pressure the deeper they go?
Water exerts more force as depth increases.
Why do oil pipelines need pumps? How do pumps work?
To move viscous oil efficiently.
Hydraulic pumps work by converting mechanical energy into hydraulic energy (fluid flow and pressure). Here's how they operate:
Input Power: A motor or engine drives the pump, providing mechanical energy.
Fluid Movement: The pump draws hydraulic fluid from a reservoir through an inlet.
Compression: The pump pressurizes the fluid by trapping it and forcing it through its system (using components like gears, pistons, or vanes).
Output: The high-pressure fluid flows to hydraulic components (like cylinders or motors) to perform work, such as lifting, pushing, or rotating.
Which flows faster—cold syrup or warm syrup? Why?
Warm syrup because heat lowers viscosity.
A rock sinks in water but a wooden block floats. Explain why.
The rock is denser than water; wood is less dense.
What is an example of compressed gas in everyday life?
CO₂ in fire extinguishers, air in tires.
Why does a sealed water bottle shrink when taken up a mountain?
Less atmospheric pressure at high altitudes.
Why is hydraulic fluid used in brakes?
Liquids are incompressible and transfer force effectively.
Why is viscosity important in motor oil selection?
Motor oil needs different viscosities for different temperatures to properly lubricate engines.
What would happen to a submarine if it increased its density? Explain.
It would sink and fill it's ballast tanks with water.
How does the compressibility of air help in car shock absorbers?
Air compresses to absorb impacts, making the ride smoother.
Why do airplane cabins need to be pressurized?
To maintain safe air pressure for breathing at high altitudes.
How do submarines use fluid density to control depth?
By adjusting water levels in ballast tanks to change overall density.