1. Fluid Dynamics Factors Affecting Fluids SCI 8: Fluids Unit
Curriculum Outcomes Addressed: - Explain quantitatively the relationship between force, area, and pressure - Explain qualitatively the relationship among pressure, volume, and temperature when liquid and gaseous fluids are compressed or heated (309-4)

2. Key Terms
Compress: To decrease the amount of space or volume available for a fluid
Expand: To increase the amount of space or volume available to a fluid

3. Density (amount of matter per unit volume)
We have studied the following properties of fluids:
Density (amount of matter per unit volume)
Volume (amount of space occupied by a fluid)
Pressure (amount of force per unit volume)
Viscosity (flow rate)
Now we will look at how these properties are related and how they influence each other and work together to determine fluid dynamics. We will also look at how temperature plays a role in determining changes in these properties.

4. Factors Affecting Fluids: TEMPERATURE and Particle Bond Strength
There is a direct relationship between temperature and the strength of bonds between particles in fluids.
As the temperature of a fluid increases, its particle bond strength decreases.
Can you think of an example of this relationship in everyday life?

5. Factors Affecting Fluids: TEMPERATURE and Particle Bond Strength
As the temperature of a fluid increases, its particle bond strength decreases.
Can you think of an example of this relationship in everyday life?
Using warm water works better when you try to remove a stain or dirt from an object because the warmth loosens the bonds between the particles, allowing them to separate better.

6. Factors Affecting Fluids: TEMPERATURE and DENSITY
As we have seen, there is a direct relationship between temperature and the density of fluids.
As the temperature of a fluid increases, its density decreases.
Can you think of an example of this relationship in everyday life?

7. Factors Affecting Fluids: TEMPERATURE and DENSITY
As the temperature of a fluid increases, its density decreases.
How can you explain this relationship using the Particle Theory of Matter?
Density columns: Cold water at the bottom, room temperature water in the middle, and hot water at the top.

8. Factors Affecting Fluids: TEMPERATURE AND VOLUME
There is a direct relationship between temperature and the amount of volume taken up by a fluid.
As the temperature of a fluid increases, the amount of volume it takes up increases. This is particularly true for gases.
Can you think of an example of this relationship in everyday life?

9. Factors Affecting Fluids: TEMPERATURE AND VOLUME
As the temperature of a fluid increases, the amount of volume it takes up increases. This is particularly true for gases.
Can you think of an example of this relationship in everyday life?
A basketball that is left outside the sun will be more pumped up than a basketball that is left outside in the cold. This is because the sun warms up the particles inside the ball, weakening the bonds between them, and allowing them to move faster, and spread farther apart, taking up more volume.

10. Factors Affecting Fluids: TEMPERATURE AND VOLUME
As the temperature of a fluid increases, the amount of volume it takes up increases.

11. Factors Affecting Fluids: TEMPERATURE AND PRESSURE
There is a direct relationship between temperature and the pressure inside a fluid.
As the temperature of a fluid increases, the pressure of a fluid in a closed space increases.
Can you think of an example of this relationship in everyday life?

12. Factors Affecting Fluids: TEMPERATURE AND PRESSURE
As the temperature of a fluid increases, the pressure of a fluid in a closed space increases.
Can you think of an example of this relationship in everyday life?
When you try to fit a gas into a smaller space (volume), the pressure inside increases. For example, when you squeeze a balloon that is filled with air, the pressure builds up inside to the point that it might burst if you decrease the volume inside too much.

13. Factors Affecting Fluids: TEMPERATURE AND VISCOSITY
As we have seen, there is a direct relationship between temperature and the viscosity of fluids.
As the temperature of a fluid increases, its viscosity decreases.
Can you think of an example of this relationship in everyday life?

14. Factors Affecting Fluids: TEMPERATURE AND VISCOSITY
As the temperature of a fluid increases, its viscosity decreases.
How can you explain this relationship using the Particle Theory of Matter?
A liquid at a warmer temperature flows more easily/quickly than a liquid at a colder temperature. For example, if you can’t get honey to flow out of its container, you can warm it up in the microwave for a few seconds until it flows out.

15. How Temperature Affects Fluids
Fill out the table below to show the relationship between temperature, compression, and fluid properties.
BOND STRENGTH
VOLUME
DENSITY
VISCOSITY
PRESSURE
As Temperature INCREASES…
As Temperature DECREASES..

16. Factors Affecting Fluids
PHET SIMULATION of how temperature and compression affect the density, volume, and pressure of fluids.

17. WATER: An Exception
Water is an exception to many fluid dynamic relationships.
Water has a greater volume at a high temperature (it goes from liquid to gas form), but when water freezes at low temperatures, its volume ALSO increases (like when you freeze a plastic bottle of water and the plastic breaks).
The density of water also doesn’t follow the typical fluids rule. Frozen water (ice) is less dense than liquid water, so ice floats in water. Could you imagine what the world would be like if water did follow the typical fluids rule that frozen fluids are more dense than liquid fluids of the same kind? What would the world look like?