fluids

Question 1

What are fluids? (Describe their shape and volume.)

Answer 1

Fluids are substances that have no fixed shape and are free to flow: liquids and gases. Liquids have a fixed volume, meaning that no matter the container they’re put into, their mass remains the same. Gases do not have a fixed volume, as their particles are farther apart.

Question 2

What is mass?

Answer 2

Mass is a measure of the amount of matter in an object or substance.

Question 3

What is weight?

Answer 3

Weight is the measurement of the force of gravity pulling on an object or substance.

Question 4

How are mass and weight different?

Answer 4

Mass refers to the amount of matter that makes up an object; it stays the same no matter where the object is—on Earth, the Moon, or any other place in the universe. Weight varies depending on the pull of gravity where the object is located.

Question 5

What is volume?

Answer 5

Volume is the amount of space occupied by an object or substance.

Question 6

How does volume relate to fluids?

Answer 6

Liquids have a fixed volume—if we were to pour 100ml of orange juice into a glass from a wide container, it would still be 100ml. Gases are different—if you were to pour a gas into a cup, the particles would spread apart and into the air. If you were to put a lid on the cup quickly after pouring, the gas would be compressed, making its volume less. Gases have no fixed volume.

Question 7

What is density?

Answer 7

Density is the measurement of the amount of matter in a given volume of an object or substance.

Question 8

How do you calculate density?

Answer 8

Mass divided by volume.

Question 9

What is viscosity?

Answer 9

The viscosity of a fluid refers to its thickness or resistance to flow.

Question 10

What is flow rate?

Answer 10

Flow rate is the amount of time it takes to pour a fluid.

Question 11

What are four factors that affect flow rate?

Answer 11

The four factors that affect flow rate are the type of fluid, the force pushing on the fluid, the size of the opening the fluid is being poured out of, and the type of surface the fluid is being poured onto.

Question 12

How do you calculate flow rate?

Answer 12

To calculate flow rate, you measure the volume of a fluid moving past a certain point in a given amount of time.

Question 13

What is the difference between cohesion and adhesion?

Answer 13

Cohesion is what holds a fluid together—Adhesion is what makes a fluid stick to things.

Question 14

What happens to fluids when pressure is applied?

Answer 14

When pressure is applied to a fluid, the fluid is compressed. Liquids are said to be incompressible.

Question 15

What effect does temperature have on the pressure of a fluid?

Answer 15

Increasing the temperature of a fluid increases its pressure, the same way decreasing the temperature of a fluid decreases its pressure.

Question 16

What factors cause an object to rise, sink, or float?

Answer 16

Buoyancy is the tendency of an object to rise or sink in a fluid. If the buoyant force on an object is less than the force of gravity on it, it will sink. If the buoyant force is more than the force of gravity on it, it will rise. If both are equal, the object will float. If the density of an object is more than the density of the fluid it’s in, it will sink. If the density of the object is less than the density of the fluid, it will rise. If both densities are equal, the object will float.

Question 17

What are the six differences between a hydraulic and pneumatic system?

Answer 17

Energy source, speed of response, degree of precision, force, complexity of piping system, and operating environment.

Question 18

What is an example of hydraulic and pneumatic systems in our everyday lives?

Answer 18

Equipment such as cranes, forklifts, jacks, pumps and fall arrest safety harnesses use hydraulics to lift and lower objects. Everyday devices like vacuum cleaners and spray cans utilize pneumatic systems.