Chapter 8 Test Study Notes

Question 1

What is viscosity?

Answer 1

The resistance of a fluid to flow. Fluids with high viscosity do not flow as easily as fluids with a low viscosity.

Question 2

What is friction?

Answer 2

A force that works to slow down motion as a result of surfaces rubbing against each other. The greater the friction, or rubbing, between particles in any fluid, the higher the viscosity. A fluid with a high viscosity has a large amount of internal friction. As the temperature of a gas increases, friction increases, and so the viscosity of the gas increases.

Question 3

Flow Rate

Answer 3

The flow rate of a fluid is a measure of the speed at which a fluid flows from one point to another. Flow rate is determined by measuring the amount of fluid that flows past a given point in a given time. The greater the viscosity, the lower the flow rate.

Question 4

What is density?

Answer 4

Density describes how closely packed together the particles are in a substance. A substance is most dense when it is a solid and least dense when it is a gas. A solid is denser than a gas because the particles in a solid are much closer together.

Question 5

What is force?

Answer 5

A push or pull that acts on an object. For example, weight is the amount of downward pull on an object due to the force of gravity. The measuring unit of force is the newton (N). One newton is approximately equal to the force you would exert to hold up a baseball.

Question 6

What is buoyancy?

Answer 6

The tendency of an object in a fluid to rise or sink due to density differences with its surroundings.

Question 7

What is buoyant force?

Answer 7

Earth’s gravitational force attracts matter downward toward Earth’s centre. A fluid, however, exerts an opposite force that pushes matter upward. The upward force exerted by a fluid is called the buoyant force.

Question 8

Plimsoll Line

Answer 8

Shows how heavily a ship can be safely loaded in different water conditions. The marks on the left indicate where the waterline should be in salt water.

Question 9

Pressure

Answer 9

The amount of force applied to a given area. Air is a fluid, and it exerts pressure around you all the time.

For example:
Air pressure is the reason why your ears may “pop” when you change altitude quickly. When the air pressure outside changes, the air pressure inside your middle-ear has to adjust, resulting in the popping sound.

Question 10

What is compression?

Answer 10

A decrease in volume caused by a force. There is a large amount of space between the particles in a gas like the air in a soccer ball. There is a large amount of space between the particles in a gas like the air in the soccer ball. There is much less space between the particles in a liquid. This means that gases are much more compressible than liquids are. In fact, very little compression occurs in liquids.

Question 11

Compressibility

Answer 11

The property of being able to be compressed.

Question 12

Incompressible

Answer 12

For example, materials in a liquid state are said to be incompressible, which means they cannot be compressed easily.

Question 13

How does temperature change viscosity in liquids?

Answer 13

An example of temperature changing viscosity in liquids is for example heating up maple syrup. Normally, maple syrup has a high viscosity and a very low flow rate. But, if you boil/heat up maple syrup a lot, it begins to lose its viscosity, and it’s flow rate increases.

Question 14

How does temperature change viscosity in gases?

Answer 14

An example of temperature changing viscosity in gases is for example
if you were to heat up smoke. Once you heat up the smoke, the particles begin to move faster. This results in them colliding with one another, which creates lots of friction. Since friction slows down the motion of a surface when it rubs together with another surface, it creates more viscosity. This results in the smoke now moving slower, and having a much higher viscosity than before.

Question 15

What is the relationship between viscosity and flow rate?

Answer 15

The relationship between viscosity and flow rate is that the higher the viscosity, the slower a substance moves. And, flow rate is how fast or slow a substance moves. So, the lower the flow rate the more viscosity a substance has, but the higher the flow rate the less viscosity a substance has. Flow rate also can help determine the viscosity of a substance.

Question 16

What is temperature’s relationship with density?

Answer 16

The relationship between density and temperature is that the higher the temperature of a substance, the more the particles move around, resulting in the substance having a higher flow rate, unless it’s a gas. And, since density describes how closely packed together the particles are in a substance, it also changes the higher or lower the temperature of a substance is. The higher the temperature of a substance, the lower the density. The lower the temperature of a substance, the higher the density.

Question 17

How do you calculate density?

Answer 17

Density is the ratio of mass to volume. The unit for measuring the density of liquids is usually grams per milliliter (g/mL). For gases, the most commonly used unit is kilograms per liter (kg/L). The unit for measuring the density of solids is usually grams per cubic centimeter (g/cm3). You can calculate the density of a substance by devising its mass by its volume.

Example:
Density (D) = mass (m)
——————volume (V)

D = m
——V

• —= 1.76 g
• —–2.0 mL

Question 18

An object will rise in a fluid if:

Answer 18

• The density of the object is less than the density of the fluid.
• The buoyant force on the object is greater than the force of gravity on the object.

Question 19

An object will sink in a fluid if:

Answer 19

• The density of the object is greater than the density of the fluid.
• The buoyant force on the object is less than the force of gravity on the object.

Question 20

An object will float in a fluid when:

Answer 20

• The density of the object is equal to the density of the fluid.
• The buoyant force on the object is equal to the force of gravity on the object.

Question 21

What is Archimedes’ Principle?

Answer 21

Archimedes’ principle states that the buoyant force on an object is equal to the weight of the fluid displaced by the object.

Question 22

What is pressure’s relationship with depth?

Answer 22

The relationship between pressure and depth is that, since water is very hard to compress, it typically has a higher pressure the lower the depth it reaches. For example, if you were to make a hole at the top and bottom of a dam, the water would exit the bottom hole with a much higher pressure than the top, because of all the pressure at the bottom.

Question 23

What is pressure’s relationship with fluid flow?

Answer 23

The relationship between pressure and fluid flow is that, if a fluid is allowed to move, it will always go from an area of higher pressure to an area of lower pressure. You make use of this property when you use a straw to drink from a juice box. Your mouth creates an area of lower pressure. The juice in the box is at a higher pressure, so it travels up the straw and into your mouth.

Question 24

What is pressure’s relationship with temperature?

Answer 24

The relationship between pressure and temperature is, for example, if you were to heat up the fluid in a juice box, the fluid’s particles would begin to vibrate and move around much more frequently. This results in the fluid bouncing and hitting the sides of the juice box, and with more energy the more you heat up the fluid. This increases the pressure of the fluid in the juice box, and can result in an explosion/popping of the juice box.

Question 25

How do you read density on a graph?

Answer 25

A substance with a greater slope on the graph has a greater density than a substance with a shallower slope.

Question 26

What are some metals more dense than water?

Answer 26

Gold, iron, and aluminum.

Question 27

What are three fluids and one solid which are less dense than water?

Answer 27

Vegetable oil, rubbing alcohol, gasoline, and pine wood.