Characteristics of Fluids
True or False
Water is the only type of Fluid
False
a fluid is a substance with no fixed shape that can flow
What is the viscosity of a fluid?
How thick a fluid is and how much it resists flowing.
Define fluid mechanics
The study of how fluids (liquids and gases) behave when they are at rest and when they are moving.
Define "surface tension"
When cohesion at the surface of a liquid that can behave like a stretchy thin “skin”.
In this lab with the ramp, which variables or factors you could change, affected the flow rate?
Type of fluid, angle/incline of the ramp, the surface of the ramp, the physical application of the fluid etc.
Give two examples of Newtonian fluids that are not water
Ex honey, liquid soap, cooking oil, gasoline, air, molasses etc.
What 4 factors can affect flow rate?
The type of fluid, the force pushing the fluid, the size of the opening it moves through, and the surface it flows across.
What are the two branches of "Fluid Dynamics"?
Aerodynamics, the study of moving gases like air Hydrodynamics, the study of moving liquids like water.
What happened to the water dome on the penny when it got to large? Why?
The water dome collapsed because the cohesion between water molecules and the adhesion of water molecules to the small penny reached its maximum amount; the surface tension was disrupted.
Which liquid (shampoo, cooking oil, dish detergent) had the highest viscosity? How did you know?
Ex the shampoo or soap because it flowed more slowly down the ramp. It was thicker, and more resistant to change.
What is the Particle Theory of Matter?
All matter is made of tiny moving particles with spaces between them. These particles are always moving, move faster when heated, and attract one another.
Explain the difference between cohesion and adhesion
Cohesion is the attraction between particles of the same substance. Adhesion is the attraction between a fluid and another material.
Give two examples of why it may be important to control the movement of a gaseous fluid like air?
Airplane wings are shaped to control how air flows over and under them so planes can lift off and remain stable in the sky. Parachutes and paragliders are carefully designed to control airflow and slow descent
What happened to the water molecules on the wax paper when you tilted the wax paper? Why?
The change in gravity decreased the distance between water molecules to adjust the cohesive attraction, and the water droplets changed shape, and/or got larger, and spread out
Explain if there is a relationship between viscosity and flow rate?
Yes there is a relationship, because the more viscous a fluid is, it is more resistant to change/flow. The more flow-resistant a fluid is, the longer it will take to flow (higher flow rate).
Imagine there was a popcorn party in the 2nd floor Staff Room. Why could you smell the popcorn?
The air is a fluid which spreads out quickly and takes up the space in the hallways etc., carrying the popcorn scent particles
Why would a firefighter need to use "wetting agents" to fight forest fires?
To reduce cohesion of the water so it spreads more easily and covers a larger area
Give two examples of why it may be important to control the movement of a liquid fluid like water?
plumbing systems, irrigation on farms, fire hoses, and water slides.
n the food industry, hydrogen gas is slowly bubbled through liquid oil when making margarine.
Dams are built to control the flow of rivers.
Why did the water drops stay rounded on the wax paper instead of spreading out?
The cohesive attraction between water molecules along with the adhesion between the water molecules and the wax paper localized the water into getting more rounded.
Rank wax paper, aluminum foil, and card stock from least resistant to most resistant.
Experiment-dependent: Ex. aluminum foil, wax paper, card stock OR aluminum foil, card stock, wax paper
Why are cars designed to be streamlined, sleek, or carefully shaped?
It encourages laminar flow of air over the car instead increasing drag from turbulent flow. Less turbulence means less resistance, allowing the car to move faster and use less energy/gas.
What is capillary action and how does it apply to our circulatory system and plant systems?
Capillary Action is the movement of a liquid through small spaces due to cohesion and adhesion. This can explain how oxygen and nutrients in the blood can spread throughout the body and how water can move upwards through plants against gravity
Why does it matter that we can control fluids? Give 3 examples of Cause & Effect Relationships
Humans cannot stop fluids from moving, but we can control how fast they move, where they go, and when they stop. Ex. bursting pipes, deoxygenation of the body, crop drought,travel safety etc
Define "surfactant" and give one example from any lab you've seen in this unit
A substance like soap that disrupts surface tension by weakening the attraction between water molecules, changing how water holds together and moves. Ex. the Pepper Lab or the Milk/Food Colouring Demonstration
Why does surface texture affect flow rate?
The surface texture changes the adhesive attraction between the fluid molecules and the surface.