A: Mix and Flow of Matter, section 3: density, temperature, and buoyancy Flashcards
(382 cards)
1
Q
Define viscosity
A
The state of being thick, sticky, and semifluid in consistency, due to internal friction.
2
Q
Will the flow rate be faster if the substance is more viscous?
A
No. More viscous means it is thicker so more viscous would make the substance thick and slow to pour.
3
Q
What determines the viscosity of a substance?
A
The question is asking: what determines if the substance will be thick or thin?
The internal resistance or friction between the particles determines the viscosity.
4
Q
What factor has an effect on viscosity?
A
Temperature
Viscosity will decrease with increased temperature because as particles move more quickly, they interact for shorter time (shorter interactions) reducing internal friction or stress and therefore decreasing viscosity.
5
Q
How can viscosity be measured?
A
Using the ramp test, you can measure viscosity.
Ramping the temperature during a flow test is a fast test method to determine the temperature dependence of a material’s viscosity. In a flow temperature ramp, the temperature is varied continuously and the instantaneous viscosity is recorded.
6
Q
What is density?
A
The amount of matter in a given volume
7
Q
What density of a substance depend on?
A
It depends on the particles of a substance and whether the substance is a solid liquid or gas
8
Q
What is the formula for density?
A
Density (d) = mass (m) / volume (v)
density is mass divided by volume
9
Q
Why can ships float?
A
Ships contain a large quantity of air and the average density of the ship is lighter than the density of water
10
Q
Under what conditions could density remain constant?
A
Density does not change as long as the temperature, pressure, and material stays the same.
Side-note:
Density is NOT constant when the temperature changes, but for liquids and solids it doesn’t change very much with temperature or pressure. Liquids and solids expand only slightly with increasing temperature, and they compress only slightly with increasing pressure, so their densities are approximately constant under most ordinary conditions.
11
Q
Why does the density change as you heat a substance?
A
As energy is added, the particles move quickly and farther apart, thus increasing the volume. The density increases because mass remains constant but the volume increases
12
Q
What is a force?
A
It is a push or pull of an object, and is measured in Newtons (N).
E.g. buoyant force, normal force, gravitational force
13
Q
What is buoyancy?
A
It is the tendency of a substance to float.
This is a force that keep a boat above water instead of sinking if the boat is designed correctly.
The boat doesn’t keep rising though since there is an opposing force of gravity pushing it towards the center of the Earth.
14
Q
Why do buoyant objects float?
A
They take up space in a fluid, pushing some of it away of displacing it causing them to float, because the fluid pushes back against the force of gravity
15
Q
What is the buoyant force?
A
The buoyant force pushes objects away from the center of the Earth (up).
16
Q
What is a flow rate?
A
How quickly a fluid can flow
17
Q
What is a plimsoll line?
A
It shows how heavily a ship can be loaded in different weather conditions
18
Q
How do hot air balloons work?
A
As the air inside the balloon is heated, the balloon becomes less dense than the surrounding air. The buoyant force of the air will push the hot air balloon upwards, until the buoyant force equals the force of gravity. At that point the balloon will remain at the same altitude (distance from the surface of the Earth).
19
Q
What is the unit used for mass in the density equation?
A
grams (g)
This can take the metric prefixes such as kilograms kg when measuring mass in general. Density is measured mostly in grams per volume rather than kg per volume, but make sure to always show your units.
20
Q
What is the unit used for volume in the density equation?
A
cm3 centimeters cubed
21
Q
What are the units used for density?
A
g/cm3
3 should be superscript as in centimeters cubed
22
Q
What is pressure measured in?
A
Pascals
23
Q
What is the formula for pressure?
A
Pressure (P)= force (N)/ area (m2)
2 should be subscript as in meters squared
Pressure is measured in Pascals which is equivalent to Newton per meter squared
24
Q
How does drinking out of a straw work?
A
When we suck on the straw that lessens the pressure on the outside in the water or fluid and increases the pressure on the inside of the straw
25
What does Pascal's Law state?
An enclosed fluid transmits pressure in all directions equally
26
What is a pneumatic device?
It is a pressure system that uses air instead of water
27
What is a hydraulic device?
It is a pressure system that uses water instead of air
28
What are the key properties of fluids?
* mass
* volume
* density
* viscosity
* flow rate
* buoyancy
## Footnote
These properties are fundamental in understanding the behavior and applications of fluids.
29
What will you be able to define after completing this section?
Viscosity and describe how temperature affects it
## Footnote
Understanding viscosity is crucial for fluid mechanics.
30
What can you calculate and compare related to fluids?
Densities and relate them to the particle model of matter
## Footnote
This involves understanding how density connects with the arrangement of particles in matter.
31
What methods can you describe to alter density in fluids?
Methods of altering density in fluids
## Footnote
Techniques may include changing temperature or pressure.
32
What concept explains buoyancy?
Buoyancy
## Footnote
This principle explains why objects float or sink in fluids.
33
What is pressure in the context of fluids?
Pressure and examples of its use
## Footnote
Pressure is a key concept in fluid dynamics and engineering applications.
34
What can you compare regarding the compressibility of fluids?
Compressibility of liquids and gases
## Footnote
Understanding compressibility is important for applications in various fields, including engineering and physics.
35
What is a fluid?
Any matter that has no fixed shape and takes the shape of its container
## Footnote
This definition includes both liquids and gases.
36
How does the air in a bicycle tire behave as a fluid?
It takes the shape of the tire
## Footnote
This illustrates the fluid property of adapting to the shape of its container.
37
What role does viscosity play in fluid applications?
It affects how fluids flow and their resistance to motion
## Footnote
Viscosity is crucial for understanding the efficiency of fluid-based systems.
38
What advantage do hydraulics provide on Earth's surface?
They make it possible for one person to lift and move huge loads
## Footnote
This principle is widely used in machinery and construction.
39
What must an engineer understand to design a hydraulic arm?
How forces are transmitted through a fluid and how fluids behave under pressure
## Footnote
This knowledge is essential for effective hydraulic system design.
40
What is viscosity?
How quickly fluids flow, determined by internal resistance or friction
## Footnote
Viscosity affects how fluids behave in different conditions.
41
What factors determine the viscosity of a fluid?
Internal resistance and friction between particles
## Footnote
Higher friction results in higher viscosity.
42
How do particles behave in a liquid compared to a gas regarding viscosity?
In a liquid, particles slide and roll over each other; in a gas, they move more freely
## Footnote
This difference affects the viscosity of each state.
43
What happens to fluids with high viscosity?
They do not flow as easily as fluids with low viscosity
## Footnote
Examples include ketchup (high viscosity) and juice (low viscosity).
44
What viscosity number range does the Society of Automotive Engineers (SAE) assign to motor oils?
Between 5 and 50
## Footnote
Higher numbers indicate higher viscosity.
45
What is an example of a motor oil suitable for summer use?
SAE 30 oil
## Footnote
It is designed for higher temperatures.
46
What does multi-grade motor oil like SAE 10W30 provide?
Easier flow at cold temperatures and resistance to thinning in heat
## Footnote
This makes it versatile for different weather conditions.
47
Fill in the blank: The greater the friction between particles in a fluid, the _______ the viscosity.
higher
## Footnote
This relationship is crucial in understanding fluid dynamics.
48
True or False: Fluids with low viscosity flow more easily than those with high viscosity.
True
## Footnote
This is a fundamental property of fluids.
49
What would happen to shampoo if it had a higher viscosity?
It would be hard to get out of the bottle
## Footnote
This illustrates how viscosity affects everyday products.
50
What would happen to shampoo if it had a lower viscosity?
You would probably use more to wash hair
## Footnote
Lower viscosity leads to increased usage.
51
What is one major factor that can affect the viscosity of a fluid?
Temperature
## Footnote
Viscosity generally decreases as temperature increases for most fluids.
52
What happens to the viscosity of syrup when poured on hot pancakes?
It decreases
## Footnote
The heat from the pancakes lowers the viscosity of the syrup, allowing it to flow more easily.
53
What is the ramp method used for?
Measuring viscosity
## Footnote
This method involves pouring a fluid down a ramp and timing how long it takes to reach the bottom.
54
What is the process for comparing the viscosities of different fluids using the ramp method?
Pour the same amount of each fluid and time them
## Footnote
This allows for a direct comparison of how quickly each fluid flows.
55
How can you investigate the effect of temperature on viscosity using the ramp method?
Test the same fluid at different temperatures
## Footnote
First test at room temperature, then warm it or cool it, and test again.
56
What happens to the viscosity of olive oil when placed in a refrigerator?
It increases
## Footnote
Cooling the olive oil in the refrigerator raises its viscosity, making it thicker.
57
What is the expected viscosity of hot tar spread on a road?
Lower viscosity
## Footnote
The heat reduces the viscosity of the tar, allowing for easier spreading.
58
What does the viscosity of engine oil do when poured into a hot engine?
Decreases
## Footnote
The heat from the engine lowers the viscosity of the oil, enabling better lubrication.
59
Fill in the blank: The ramp method involves _______ a fluid down a ramp.
pouring
## Footnote
This method is essential for measuring how fast different fluids flow.
60
What is viscosity?
Viscosity is a fluid's internal resistance or friction that keeps it from flowing
## Footnote
Viscosity determines how easily a fluid flows; high viscosity means high resistance.
61
How does temperature affect viscosity?
As the temperature of a liquid increases, its viscosity decreases; as temperature decreases, viscosity increases
## Footnote
This relationship is crucial in understanding fluid dynamics.
62
What happens to the flow of a fluid as its temperature increases?
The fluid flows faster
## Footnote
Increased temperature provides energy that allows particles to move more freely.
63
What is the particle model of matter?
The particle model states that a liquid is made of particles that can slide and roll over each other
## Footnote
This model helps explain the behavior of liquids, including viscosity.
64
What effect does adding heat to a liquid have on its particles?
The particles slide and roll more quickly
## Footnote
This increased motion results in lower viscosity.
65
What happens to viscosity when the temperature of a liquid drops?
Viscosity increases
## Footnote
The particles slow down, leading to slower fluid flow.
66
Fill in the blank: A fluid with a _______ viscosity has a large amount of internal resistance or friction.
high
67
How did Aboriginal peoples in Alberta use viscous materials?
They used thick, viscous bitumen from the oil sands to seal their canoes
## Footnote
This demonstrates an understanding of fluid characteristics in practical applications.
68
What material did Aboriginal peoples use to make glue for building canoes?
Tree sap
## Footnote
Tree sap was utilized for its adhesive properties, showcasing knowledge of fluid characteristics.
69
True or False: Higher temperatures always result in higher viscosity.
False
## Footnote
Higher temperatures actually decrease viscosity.
70
What is the reason the grape sinks in some liquids and not in others?
The reason is a property of fluids called density.
71
Define density.
Density is the amount of matter in a given volume.
72
How should density be considered when examining the results of an investigation?
Think about density as you examine the results.
73
Fill in the blank: Density is the amount of matter in a given _______.
[volume]
74
True or False: Density is not relevant to the sinking of the grape in liquids.
False
75
What does the particle model of matter state?
All matter is made of tiny particles, and different substances are made of different particles.
76
How does the density of a fluid relate to its particles?
The density of a fluid depends on the particles it is made of.
77
If the density of an object is greater than the density of the fluid, what happens?
The object sinks.
78
If the density of an object is less than the density of the fluid, what happens?
The object floats.
79
What is the formula for calculating density?
Density (d) = Mass (m) / Volume (V)
80
What are the common units for the density of liquids and gases?
Grams per millilitre (g/ml) or kilograms per litre (kg/L).
81
What are the common units for the density of solids?
Grams per cubic centimetre (g/cm³).
82
What is the density of water at room temperature?
1.00 g/ml.
83
What is the density of mercury at room temperature?
13.55 g/mL.
84
Fill in the blank: Density is the mass per unit of _______.
volume.
85
True or False: Some solids can be less dense than some liquids.
True.
86
What determines a substance's density?
The kind of particles in the substance.
87
What is an example of a substance that floats on water?
Wood.
88
What is the significance of Emma's results on page 42?
They illustrate how the density of an object compared to a fluid determines whether it sinks or floats.
89
What is the density of isopropyl (rubbing alcohol)?
Not specified in the text.
90
What is the density of gold?
Not specified in the text.
91
What is the density of aluminum?
Not specified in the text.
92
What is the density of iron?
Not specified in the text.
93
What is one reason a can of diet soda floats in water while a can of regular soda does not?
The difference in density between the two cans.
94
What happens to density if temperature remains constant?
Density does not change as long as the temperature stays the same.
95
What device is used to measure the density of liquids?
Hydrometer
96
What is the procedure to determine if the density of cold water is the same as hot water?
Use a hydrometer to measure the density of both cold and hot water.
97
True or False: Warm water has a higher density than cold water.
False
98
According to the particle model, what happens to particles when energy is added?
Particles move more quickly.
99
What is the relationship between particle movement and state changes in matter?
As a solid changes to a liquid and then to a gas, the particles move faster.
100
What happens to the volume of a substance as its particles become more active?
The volume increases.
101
Fill in the blank: Density is the ratio of ______ to volume.
[mass]
102
How does an increase in volume affect density with a constant number of particles?
Density decreases.
103
What explains the phenomenon of warm water floating on cold water in a lake?
Warm water has a lower density than cold water.
104
What is the effect of temperature on the density of a substance?
Density changes with temperature due to particle movement.
105
What must be done if hot water spills on your skin?
Immediately run cold water over the area.
106
What happens to a substance as it is heated?
It changes state from solid to liquid to gas.
## Footnote
This process is known as phase transition.
107
Which state of a substance typically has the greatest density?
Solid state.
## Footnote
This is true for most substances except water.
108
What is the order of states for a substance as temperature increases?
Solid, Liquid, Gas.
## Footnote
This order reflects the typical phase changes of substances.
109
How does the particle model explain density differences in states of matter?
Particles in a solid are packed closely together, while particles in a gas have more space between them.
## Footnote
This explains why solids are denser than liquids and gases.
110
True or False: A gas has a greater density than a solid.
False.
## Footnote
Gases have less density than solids.
111
Fill in the blank: A substance (except water) has a greater density in its _______ state than in its liquid and gas states.
solid
## Footnote
This property is common among most substances.
112
What does Galileo's thermometer use to indicate temperature?
Temperature bulbs that act like a hydrometer.
## Footnote
The bulbs float based on the density of the surrounding water.
113
When does a temperature bulb in Galileo's thermometer float to the top?
When the water's density is greater than that of the bulb.
## Footnote
This demonstrates the principle of buoyancy.
114
What state of matter is least dense?
Gas state.
## Footnote
This is a general characteristic of gases compared to solids and liquids.
115
In which state are particles packed closely together?
Solid.
## Footnote
This close packing contributes to the high density of solids.
116
What is the density of distilled water?
1 g/mL
117
Why is it easier to float in salt water than in fresh water?
Salt water has a higher density than fresh water
118
What happens when salt is added to distilled water?
The density of the water solution increases
119
What effect does increasing the concentration of salt have on the density of water?
It increases the density of the water solution
120
What determines whether an object will float in a liquid?
The density of the object compared to the density of the liquid
121
Fill in the blank: Less dense objects float in _______ substances.
more dense
122
True or False: Density is the only factor that affects whether an object floats.
False
123
What is the relationship between the number of particles in a volume and density?
More particles in a volume increase the density
124
What is the role of the particle model of matter in understanding density?
It explains how dissolving one substance in another increases the number of particles
125
What body of water is mentioned as one of the saltiest on Earth?
The Dead Sea
126
What happens to an object when its density is greater than the density of the fluid it is in?
The object sinks.
127
What force pulls an object downward when it is in a liquid?
The force of gravity.
128
What is the force called that pushes an object upward when it is in a liquid?
Buoyant force.
129
What occurs when the density of the liquid is greater than the density of the object?
The object floats.
130
What happens when the density of the object is greater than that of the liquid?
The object sinks.
131
Define buoyancy.
The tendency of an object to float when placed in a fluid.
132
What is buoyant force?
The force in fluids that acts against gravity.
133
What allows a diver to move downward in water?
The combined force of gravity and leg movement is greater than the buoyant force.
134
What allows a diver to move upward in water?
The combined buoyant force and leg movement is greater than the force of gravity.
135
What is it called when the force of gravity equals the buoyant force?
Neutral buoyancy.
136
What is a practical application of buoyancy in transportation technologies?
Ships are designed to float safely.
137
Fill in the blank: When a ship moves from more dense to _______ water, its buoyancy is affected.
less dense
138
What is the property that describes a liquid's thickness or thinness?
Viscosity
## Footnote
Viscosity is a key property of all fluids, including both liquids and gases.
139
How does viscosity differ between liquids and gases?
Viscosity in gases increases and decreases differently than in liquids
## Footnote
Gases are often harder to visualize regarding viscosity due to their invisibility.
140
What term is used to describe how fast a fluid 'runs'?
Flow rate
## Footnote
Flow rate can be measured by the time it takes for the fluid to travel from one point to another.
141
What factors might affect the flow rate of a liquid?
Properties of fluids
## Footnote
Variables such as viscosity, temperature, and the nature of the fluid can influence flow rate.
142
What is the effect of higher viscosity on the flow of a liquid?
A thicker liquid flows more slowly
## Footnote
Higher viscosity indicates a greater resistance to flow.
143
Fill in the blank: A thicker liquid has a _______ viscosity.
higher
## Footnote
Higher viscosity means the liquid is more resistant to flow.
144
What is an example of a liquid that flows thickly?
Chocolate syrup
## Footnote
Other examples include honey and caramel.
145
True or False: Viscosity is a property of only liquids.
False
## Footnote
Viscosity is a property of all fluids, including gases.
146
What might you predict about the flow of different fluids in a pan?
The order of flow based on viscosity
## Footnote
Thicker liquids will typically flow slower than thinner liquids.
147
Why is it important to determine the flow rate of a liquid?
The viscosity of liquids must be measured precisely in some industries
## Footnote
For example, the viscosity of paints and varnishes is closely regulated for smooth application.
148
Which industry depends on the flow properties of matter?
The cosmetics industry
## Footnote
Specifically, products like lipstick require careful viscosity management.
149
What is the state of lipstick when sold?
Solid
## Footnote
Unlike nail polish and mascara, lipstick is a solid mixture.
150
What processes are involved in the manufacture of lipstick?
Heating, dissolving, melting, mixing, grinding, straining, pouring, and cooling
## Footnote
These steps ensure proper formulation and consistency.
151
What two mixtures are prepared in the lipstick manufacturing process?
One contains oils and antioxidants, and the second contains dissolving ingredients (solvents)
## Footnote
Mainly alcohol is used in the second mixture.
152
What is the purpose of heating the two mixtures in lipstick production?
To allow complete mixing
## Footnote
This ensures that all ingredients blend properly.
153
What is done to the pigment mixture in lipstick production?
It is blended with colour pigments or dyes and passed through a large roller mill
## Footnote
This grinds the grainy pigment to ensure a smooth product.
154
What types of waxes are used in lipstick production?
Beeswax, candelilla wax, and carnauba wax
## Footnote
These waxes help the final product hold its distinctive shape.
155
What happens to the lipsticks after cooling?
They are inspected for undesirable marks
## Footnote
This includes checks for mold separation lines and air holes.
156
What is done if the lipsticks do not meet quality standards?
They are removed, remelted, and remoulded
## Footnote
This process ensures only acceptable products are packaged.
157
How was furniture stripping liquid improved?
The viscosity was increased to a gel-like texture
## Footnote
This change made the product easier to apply and helped it stick to surfaces.
158
True or False: The viscosity of paints and varnishes is not regulated.
False
## Footnote
Viscosity is closely regulated to ensure proper application.
159
What is viscosity?
The measure of a fluid's resistance to flow.
160
How does nail polish behave when applied?
Applied as a slick fluid, it dries into a solid finish.
161
What is the effect of solvent on products like nail polish and mascara?
Controls viscosity; too little makes application difficult, too much slows drying.
162
Why do chefs need to adjust the viscosity of gravies and sauces?
To achieve the desired thickness for different culinary applications.
163
What must mechanics consider regarding engine oil?
The viscosity appropriate for the current season.
164
Why is viscosity important for artists using oil paints or acrylics?
They need to thin or thicken the paints for application.
165
What is the role of viscosity in food manufacturing?
Ensures products like ice cream toppings and sauces have the right consistency.
166
How do food manufacturers regulate viscosity with heat?
By controlling temperature to achieve the desired consistency of products.
167
What is a specific requirement for chocolate coating in candy bars?
Must be at the right consistency and temperature to cover evenly.
168
Fill in the blank: Your mouth is highly sensitive to _______.
viscosity.
169
True or False: Viscosity only matters for food products.
False.
170
List four occupations that require knowledge of fluid viscosity.
* Candy maker
* Glass blower
* Baker
* Mechanic
171
What is a suggested activity to learn about viscosity in different occupations?
Job shadowing someone in a related field.
172
What should you do after job shadowing someone?
Take notes on viscosity's role and write a thank-you letter.
173
What is viscosity?
The resistance to flow in liquids
## Footnote
Viscosity is influenced by internal friction and the attractive forces between particles.
174
Why do some liquids flow more slowly than others?
Because they have different viscosities
## Footnote
Different internal friction levels affect how easily particles can move past each other.
175
What creates internal friction in a liquid?
Resistance to flow caused by attractive forces between particles
## Footnote
Friction occurs when two surfaces or particles interact.
176
Why is it easier to skate on ice than on pavement?
The friction between skates and ice is less than that between skates and pavement
## Footnote
This demonstrates how different surfaces affect motion.
177
How do water particles compare to oil particles in terms of flow?
Water particles slip past each other easily, while oil particles have more internal friction
## Footnote
Oil's stronger attractive forces slow down its flow.
178
What happens to the attractive forces between particles as temperature increases?
They decrease
## Footnote
Higher temperatures allow particles to move more freely.
179
What happens to the viscosity of a liquid when it is heated?
It decreases
## Footnote
Warmer liquids flow more quickly due to reduced internal friction.
180
What happens to the viscosity of a liquid when it is cooled?
It increases
## Footnote
Cooler liquids have stronger attractive forces, causing them to flow more slowly.
181
Fill in the blank: The viscosity of a liquid __________ as it is heated.
DECREASES
182
Fill in the blank: The viscosity of a liquid __________ as it is cooled.
INCREASES
183
True or False: All fluids flow at the same rate.
False
## Footnote
Different viscosities result in varying flow rates.
184
What does the particle model explain about liquids?
Attractive forces exist between particles
## Footnote
This model helps to understand how viscosity varies among different liquids.
185
How does the viscosity of gases compare to that of liquids?
Gases generally flow more easily than liquids.
186
What is the primary reason gas particles flow differently than liquid particles?
Gas particles are far apart, and the attractive forces are low.
187
How do gas particles typically interact with each other?
Gas particles are more likely to collide with each other than rub against each other.
188
What happens to the viscosity of a gas when it is flowing through a constriction?
It moves in one direction.
189
What is the effect of low energy gas particles on viscosity?
If gas particles have low energy and move in the same direction, viscosity is low.
190
What occurs when gas particles gain energy?
Their motion increases in all directions, increasing the number of collisions.
191
What is the relationship between internal friction and gas flow when gas particles have high energy?
Internal friction is high, and the gas does not flow as easily or quickly.
192
How does temperature affect the viscosity of gases?
Viscosity INCREASES as gases are HEATED and DECREASES as they are COOLED.
193
What happens to gas particles when they are heated?
They gain energy and move faster, increasing the number of collisions.
194
How do cooler gases behave in terms of particle collisions?
Cooler gases contain particles that are not colliding as much or as often.
195
True or False: The viscosity of gases decreases as they are heated.
False
196
Fill in the blank: The viscosity of a gas _______ when it is heated.
INCREASES
197
Fill in the blank: The viscosity of a gas _______ when it is cooled.
DECREASES
198
Can the solid state be less dense than the liquid state of the same substance?
Yes
## Footnote
Ice cubes float in water because solid ice is less dense than liquid water.
199
What is density in scientific terms?
Mass per unit volume of a substance
200
How can density be described in everyday language?
As the 'crowdedness' of the particles that make up matter
201
What determines the unique density of each substance?
The size of the particles and how close together they are
202
What does the particle model help to explain about matter?
Different substances have different-sized particles and empty space between them
203
Fill in the blank: Density can be described as the _______ of the particles that make up matter.
[crowdedness]
204
What happens to solid objects when they move through liquids and gases?
They can move easily through them
205
Why can dolphins leap through air and dive underwater smoothly?
Fluid properties of water and air allow particles to move out of the way
206
True or False: Solid particles tend to hold together while fluid particles tend to move apart.
True
207
How does the presence of larger spaces among people affect density on an elevator?
It reduces the density (crowdedness)
208
What visual analogy is used to explain density in the context of people on an elevator?
A large 'spacing box' around each person
209
How does the density of a substance relate to its physical state?
The density varies with physical state; gases are less dense than liquids, which are less dense than solids.
210
Why does water vapour have a lower density than liquid water?
Water vapour has fewer particles than liquid water due to more space between gas particles.
211
What happens when you step onto the surface of a lake?
Your foot pushes the water particles out of the way; liquids cannot support objects like solids can.
212
What allows a solid object to pass through a liquid?
The particles of a liquid move apart easily due to weak attractive forces between them.
213
True or False: Liquid particles have a strong attraction for each other.
False
214
Why is it easier to run through air than through water?
Air is less dense and you move through mostly empty space, requiring less effort to move particles.
215
How do the densities of gases compare to those of liquids?
Gases are generally less dense than liquids.
216
Fill in the blank: 'Empty space' means a separation between two objects with _______.
nothing between those objects, not even air particles.
217
What is a key difference between empty space and air?
Empty space does not contain air particles, while air is a mixture of gases.
218
Why can't astronauts venture outside their spacecraft without masks and air tanks?
Because there is no oxygen in outer space.
219
What can you determine by dropping small items into water?
You can determine if the items are denser than water.
220
What should you do to organize your observations about density in a Science Log?
Create a table to organize the observations.
221
What is the density of hydrogen at 20°C?
0.00009 g/ml
## Footnote
Hydrogen is one of the lightest substances and has a very low density.
222
What is the density of mercury?
13.55 g/ml
## Footnote
Mercury is one of the densest substances known.
223
How does the density of solid substances generally compare to their liquid state?
The density of the solid state is greater than the density of the liquid state
## Footnote
This is true for most pure substances, with ice being an exception.
224
Fill in the blank: As temperature increases, a substance will change from solid, to liquid, to _______.
gas
## Footnote
This process is a result of particles gaining energy.
225
Why can particles in a solid not be pushed apart?
Attractive forces among the particles of a solid are stronger than those between fluid particles
## Footnote
This creates a tightly packed arrangement.
226
What happens to the density of a substance as it is heated?
The density decreases
## Footnote
This occurs because the particles spread out and take up more space.
227
True or False: Ice is denser than water.
False
## Footnote
Ice is less dense than liquid water, which is why it floats.
228
What is a unique property of some solid metals like copper and nickel when placed in mercury?
They can float on mercury
## Footnote
This is due to the high density of mercury compared to the solid metals.
229
List three common substances with their approximate densities at 20°C from the provided table.
* Air: 0.0014 g/ml
* Water: 1.00 g/ml
* Glycerol: 1.26 g/ml
## Footnote
These densities are crucial for understanding buoyancy and fluid dynamics.
230
How does the particle model explain the change in state from solid to gas?
Particles spread out as they gain energy when heated
## Footnote
This model illustrates the behavior of matter under thermal influence.
231
Fill in the blank: The particles in a solid cannot be pushed apart because they are held together by _______.
strong attractive forces
## Footnote
This is a key difference between solids and fluids.
232
What is density?
Density is a way of expressing a mass-to-volume ratio
## Footnote
Density can be calculated using the formula: Density = Mass/Volume.
233
How can you measure the density of a substance?
By measuring the mass and volume of the substance
## Footnote
Mass is measured in grams (g) or kilograms (kg), and volume can be measured in litres or millilitres.
234
What is mass?
Mass is the amount of matter in a substance
## Footnote
Mass is measured using a balance.
235
What is volume?
Volume is a measurement of the amount of space occupied by a substance
## Footnote
Volume can be measured directly or indirectly depending on the shape of the solid.
236
How is the volume of a solid with a regular shape calculated?
Using the formula V = L x W x H
## Footnote
L is length, W is width, and H is height.
237
How can the volume of an irregularly shaped object be determined?
By measuring the volume of the water that spills out of an overflow can
## Footnote
This method is known as water displacement.
238
What is the difference between mass and weight?
Mass is the amount of matter, while weight is the force of gravity exerted on an object
## Footnote
Weight is measured in newtons (N).
239
What is the force of gravity on Earth for every kilogram of mass?
9.8 N
## Footnote
This force is almost the same everywhere on Earth's surface.
240
What is capacity?
Capacity is the greatest amount of fluid that a container can hold
## Footnote
Capacity is usually measured in litres or millilitres.
241
How is the mass-to-volume ratio expressed?
As a quantity of the mass divided by its volume
## Footnote
This ratio is what defines density.
242
True or False: Weight is measured in kilograms.
False
## Footnote
Weight is measured in newtons (N), while mass is measured in kilograms (kg).
243
Fill in the blank: The pull of gravity on a 2.26 kg bag of sugar is _____ N on Earth.
22.1 N
## Footnote
This calculation is based on the force of gravity of 9.8 N/kg.
244
What is buoyancy?
The tendency for materials to rise or float in a fluid.
245
What is another term for buoyancy?
Buoyant force.
246
What does buoyant force refer to?
The upward force exerted on objects submerged in fluids.
247
What role does buoyancy play in transportation?
It allows matter to be transported from one place to another.
248
What are some examples of how buoyancy is observed in nature?
* Nutrients transported through the bloodstream
* Pollen floating in the air
* Boats and planes moving around the world.
249
What is required for an object to float in a fluid?
The ability of the fluid to support the object.
250
What happens when an object is floating?
It does not fall in air or sink in water, but remains suspended in the fluid.
251
What force do the particles of a fluid exert?
A force in a direction opposite to the force of gravity.
252
How does gravity affect objects in fluids?
Gravity pulls down, toward the center of Earth.
253
What pushes objects up in a fluid?
Buoyant force.
254
How is buoyant force measured?
In newtons (N).
255
True or False: Buoyancy allows for the floating of icebergs, sailboats, and oil rigs.
True.
256
Fill in the blank: The buoyant force pushes objects ______ from Earth.
up.
257
What is the primary question addressed in the text regarding travel in air and water?
How can people travel in the air and on water if the density of their bodies is greater than the density of both these fluids?
258
What factor is suggested to not be the only explanation for why fluids can support certain substances?
Density
259
What is indicated as a critical aspect in determining whether an object floats or sinks?
Design
260
What does the Hibernia oil rig demonstrate about density and buoyancy?
It can float on water despite having a mass of more than 14,000 t.
261
What happens to a straight pin when placed in water?
It sinks.
262
Fill in the blank: Water can support objects that have densities greater than water, as long as the weight of the object is spread over a _____ enough area.
large
263
True or False: Density is the only factor that determines whether an object will sink or float in a fluid.
False
264
What is the mass of the Hibernia oil rig?
More than 14,000 t.
265
What is the mass of the straight pin mentioned in the text?
Slightly less than 1 g.
266
What does the Dead Sea contain that affects buoyancy?
Many salts
## Footnote
The high salt concentration increases the density of the water, allowing people to float effortlessly.
267
How long did it take for submersibles to free-fall to the Titanic wreck?
3 hours
## Footnote
This duration is specified for a depth of 650 km.
268
What is the density of steel?
9.0 g/cm³
269
What is required for a ship to float despite being made of steel?
Large, hollow hulls
## Footnote
This ensures the average density of the ship is less than that of water.
270
What does a life jacket do to a person's average density?
Lowers it
271
What is the average density of a solution?
An average of the densities of its components
## Footnote
Solutions contain more than one pure substance.
272
Why is average density useful for floating objects?
It enables objects that would otherwise sink to float
## Footnote
Examples include large ships and oil rigs.
273
What organ in fish helps control their depth in water?
Swim bladder
274
How does the swim bladder function in fish?
It contains a mixture of air and water
## Footnote
The amount of air inside the sac determines the fish's depth.
275
What adaptation from fish is used in submarines for depth control?
Swim bladder mechanism
276
Fill in the blank: The average density of a ship must be _______ than that of water to float.
less
277
True or False: The density of a solution is equal to the density of the pure substances it contains.
False
## Footnote
The density of a solution is an average density.
278
What is the primary function of ballast in a submarine?
To control buoyancy by adjusting the amount of water and air in the tank
## Footnote
Ballast tanks fill with water to sink and pump air out to rise.
279
What happens to a submarine when it pumps air out of the ballast tank?
It sinks
## Footnote
Reducing the volume of air increases the density, causing it to submerge.
280
What is the buoyant force of air compared to water?
Much smaller
## Footnote
This difference in buoyant forces is crucial for floating objects.
281
What gas fills the Goodyear blimp?
Helium
## Footnote
Helium is the second lightest gas and contributes to the blimp's buoyancy.
282
Why can a blimp float?
Its mass is relatively small compared to its volume
## Footnote
The average density of the blimp is less than that of the surrounding air.
283
Who established the relationship between the size of an object and the buoyant force exerted on it?
Archimedes
## Footnote
Archimedes' principle is fundamental in understanding buoyancy.
284
Fill in the blank: Airships like blimps can float because their average density is _______ than that of the surrounding air.
less
## Footnote
This density difference allows them to rise.
285
What would likely happen if you dropped a sheet of paper from a height into a small box?
It would not land directly in the box
## Footnote
The paper's shape and mass affect its descent.
286
What could you do to help a sheet of paper hit its target when dropped?
Fold it or crumple it
## Footnote
Altering the shape increases its descent stability.
287
True or False: A wooden block will fall straight down like a sheet of paper.
False
## Footnote
The wooden block has a different shape and mass distribution affecting its fall.
288
What do ocean-going ships, hot-air balloons, and blimps have in common?
They all have huge volumes
## Footnote
Their volume contributes to their buoyancy in their respective mediums.
289
Who discovered Archimedes' Principle?
Archimedes
## Footnote
Archimedes was a Greek scientist who lived around 212 B.C.E.
290
What was the main task given to Archimedes by Hiero II?
To determine if the crown was made entirely of gold
291
What two values are required to calculate density?
Mass and volume
292
How did Archimedes measure the mass of the crown?
With a balance
293
What was the challenge Archimedes faced in measuring the crown?
Measuring the volume of an irregularly shaped object
294
What discovery did Archimedes make while at the public baths?
A solid object can displace water out of a container
295
How did Archimedes determine the volume of the crown?
By submerging it in water and measuring the displaced water
296
What conclusion did Archimedes reach after testing the crown?
The crown was made of a mixture of gold and silver
297
True or False: Archimedes concluded that the goldsmith had used pure gold for the crown.
False
298
Fill in the blank: Archimedes showed that the goldsmith tried to _______ the king.
cheat
299
Who discovered Archimedes' Principle?
Archimedes
## Footnote
Archimedes was a Greek scientist who lived around 212 B.C.E.
300
What was the main task given to Archimedes by Hiero II?
To determine if the crown was made entirely of gold
301
What two values are required to calculate density?
Mass and volume
302
How did Archimedes measure the mass of the crown?
With a balance
303
What was the challenge Archimedes faced in measuring the crown?
Measuring the volume of an irregularly shaped object
304
What discovery did Archimedes make while at the public baths?
A solid object can displace water out of a container
305
How did Archimedes determine the volume of the crown?
By submerging it in water and measuring the displaced water
306
What conclusion did Archimedes reach after testing the crown?
The crown was made of a mixture of gold and silver
307
True or False: Archimedes concluded that the goldsmith had used pure gold for the crown.
False
308
Fill in the blank: Archimedes showed that the goldsmith tried to _______ the king.
cheat
309
What does the buoyant force of a liquid depend on?
Density
## Footnote
The buoyant force does not depend on the physical state of the liquid, but rather on its density.
310
What is the density of seawater?
1.03 g/mL
## Footnote
Seawater has a higher density than fresh water, which has a density of 1.00 g/mL.
311
What is the density of fresh water?
1.00 g/mL
## Footnote
Fresh water has a lower density compared to seawater.
312
How does the density of salt water compare to that of fresh water?
Salt water has a greater density than fresh water
## Footnote
This means salt water can support more weight per volume.
313
What happens to a hydrometer in a liquid with higher density?
It extends farther out of the liquid
## Footnote
For example, a hydrometer will float higher in water (1 g/mL) than in vegetable oil (0.9 g/mL).
314
What is the primary use of a hydrometer?
To measure liquid density
## Footnote
Hydrometers are commonly used in various industries, including food and beverage.
315
True or False: A hydrometer can determine sugar content directly.
False
## Footnote
Hydrometers measure density, which can be used to indirectly determine other values like sugar content.
316
Fill in the blank: The relationship between _______ and density is the basis for the hydrometer.
buoyancy
317
What observation can be made about floating in salt water compared to fresh water?
Objects float more easily in salt water
## Footnote
This is due to the higher density of salt water.
318
What industries widely use hydrometers?
Food and beverage industries
## Footnote
Hydrometers are designed for specific uses in these industries.
319
What does a hydrometer indicate when it sinks lower in a liquid?
The liquid has a lower density
## Footnote
For example, it sinks lower in vegetable oil than in water.
320
What does the buoyant force of a liquid depend on?
Density
## Footnote
The buoyant force does not depend on the physical state of the liquid.
321
How does the density of seawater compare to that of fresh water?
Seawater has a density of 1.03 g/mL, while fresh water has a density of 1.00 g/mL
## Footnote
This means seawater is denser than fresh water.
322
What effect does the density of salt water have on buoyancy?
Salt water can support more weight per volume than fresh water
## Footnote
This is why objects float more easily in salt water.
323
What is the purpose of a hydrometer?
To measure liquid density
## Footnote
Hydrometers are instruments that extend farther out of a liquid with higher density.
324
What happens to a hydrometer in a liquid with lower density, such as vegetable oil?
It will sink lower
## Footnote
Vegetable oil has a density of 0.9 g/mL, which is lower than that of water.
325
In which industries are hydrometers widely used?
Food and beverage industries
## Footnote
Hydrometers can determine values indirectly, such as sugar or alcohol content.
326
Fill in the blank: The relationship between buoyancy and density is the basis for the _______.
hydrometer
327
True or False: The buoyant force is the same for all liquids regardless of their density.
False
## Footnote
Buoyant force varies with the density of the liquid.
328
What density does water have?
1 g/mL
329
How does the packing of particles in salt water compare to that in fresh water?
Particles in salt water are packed together more tightly
## Footnote
This increased packing contributes to its higher density.
330
What is the effect of swimming in the ocean compared to a freshwater body in terms of buoyancy?
It is easier to float in the ocean
## Footnote
The higher density of seawater provides more buoyant force.
331
What is an example of a better landing surface for a stunt double?
A huge, billowy air mattress
## Footnote
The air mattress absorbs the force of the fall gradually, reducing pressure on the body.
332
What is required for the compression of a gas to occur?
1. The gas must be enclosed in a sealed container with sturdy walls.
2. There must be space between the particles.
3. An external force is applied to the gas
## Footnote
Gases can be compressed because their particles can be pushed closer together.
333
Are gases, liquids, and solids compressible?
Gases are compressible; solids and liquids are almost incompressible
## Footnote
Although solids and liquids have some space between particles, they cannot be squeezed into a smaller volume.
334
What happens to liquids and solids when an external force is applied?
The applied force is transmitted from one particle to the next, without changing the volume
## Footnote
This transmission of force is similar to falling dominoes.
335
Fill in the blank: Gases are _______ because their particles can be squeezed closer together.
compressible
336
Fill in the blank: Solids and liquids are said to be almost _______ because they cannot be squeezed into a smaller volume.
incompressible
337
How do particles in a solid or liquid respond to an external force?
They do not move in the direction of the force, as there is no space to move
## Footnote
Only particles with space to move will move when force is applied.
338
True or False: The spaces between particles in solids and liquids are large enough to allow for easy compression.
False
339
What role does an external force play in the compression of gases?
It pushes the particles closer together
## Footnote
This external force is necessary to achieve the compressibility of gases.
340
List some examples of materials that absorb force to reduce pressure felt during impact.
* Mats in gymnastics
* Piston-like devices in bicycles
* Styrofoam packaging
341
What is pressure?
Pressure is a measure of the force acting perpendicular to a unit area.
342
What happens when you press your hand against a wall?
You are applying pressure on that particular area of the wall.
343
What occurs if the force applied to a surface is increased?
The pressure will increase.
344
How does pressure change if the area is increased?
Pressure will decrease if the area is increased.
345
What is the formula for calculating pressure?
Pressure (P) = Force (F) / Area (A)
346
In which units is force measured?
Force is measured in newtons (N).
347
How is area commonly measured?
Area is often measured in square metres (m²).
348
What is the unit for pressure?
The unit for pressure is newtons per square metre (N/m²) or pascal (Pa).
349
What is a kilopascal (kPa) in relation to pascals?
A kilopascal (kPa) is equal to 1000 pascals (Pa).
350
Who is the pascal unit named after?
The pascal unit is named after the French scientist Blaise Pascal.
351
What was Blaise Pascal's contribution to the understanding of fluids?
He discovered that the pressure exerted on a fluid in a closed container at one end could be felt undiminished at the other end.
352
At what age did Blaise Pascal publish a geometry book?
He published a geometry book at the age of 16.
353
What did Blaise Pascal invent by the age of 19?
He invented the first mechanical calculator.
354
Fill in the blank: Pressure is calculated using the formula P = F / _______.
A
355
True or False: The unit pascal is named in honor of Blaise Pascal's work with sound.
False
356
What is a key property of gases when they are compressed?
They exert a counterforce when compressed.
## Footnote
This property is useful for cushioning shocks.
357
How does air in a car tire function under the weight of the car?
It pushes back against the force exerted by the weight of the car.
## Footnote
This prevents the car from sinking to the ground.
358
What happens to the air in tires when a car hits a bump?
The extra force compresses the air further, spreading the effect over the tire.
## Footnote
This prevents direct transmission of force to the car body.
359
What occurs when the extra force on a tire is removed?
The air returns to its original volume and the tire resumes its original shape.
## Footnote
This demonstrates the elasticity of gases.
360
What is the purpose of an air bag in an automobile?
To cushion shocks during a collision.
## Footnote
Air bags are designed to be used in addition to seat belts.
361
What components are included in an air-bag system?
Crash sensors, an ignitor, gas generator, and an inflatable nylon bag.
## Footnote
The nylon bag is stored in the steering wheel or dashboard.
362
At what speeds do impact sensors typically trigger an air bag deployment?
Speeds in excess of 15-20 km/h.
## Footnote
This threshold ensures activation during significant impacts.
363
What gas is produced to inflate an air bag during a collision?
Harmless nitrogen gas.
## Footnote
This gas is generated through an explosive chemical reaction.
364
How quickly does the air-bag deployment process occur?
In only 0.04 seconds.
## Footnote
This rapid deployment is crucial for driver safety.
365
What is believed to be superior in some running shoes compared to plain rubber soles?
Compressed air for shock absorption and bounce.
## Footnote
This design enhances comfort during running.
366
Fill in the blank: An air bag in an automobile uses _______ to protect the driver in a collision.
compressed air
## Footnote
This technology is vital for reducing injury risk.
367
What is the thickness of Earth's atmosphere?
Approximately 160 km
368
What keeps the envelope of air around Earth?
Gravity
369
Why don't you feel weighed down by air?
Air pressure is balanced by your body pressure
370
How does air pressure change with altitude?
Decreases as you climb higher
371
What happens to the air pressure inside your body as you climb a mountain?
It does not change quickly
372
What is the function of the eardrum in relation to air pressure?
Moves in response to differences in air pressure
373
What occurs when there is a great difference in pressure on either side of the eardrum?
You experience a 'pop' in your ear
374
What is the most common device for measuring air pressure?
Barometer
375
What substance was used in the earliest barometers?
Mercury
376
How does a mercury barometer work?
Mercury falls in a tube creating a vacuum at the top
377
What happens when air pressure pushes down on mercury in a barometer?
It forces mercury up the column
378
What is the maximum air pressure that can support mercury at sea level?
760 mm of mercury (Hg)
379
What occurs if the inside of a closed container has lower air pressure than the outside?
The walls of the container will buckle
380
What happens to a juice box when you drink from a straw?
The box buckles inward due to lower air pressure inside
381
Fill in the blank: Air pressure can support _______ mm of mercury at sea level.
760
382
True or False: The air pressure inside your body changes rapidly as you ascend to higher altitudes.
False
