Archimedes’ Principle

Bernoulli’s Principle

Pascal’s Principle

Properties of Fluids

- Lucas Kraschnewski Howard, WI

ECOMP 5016

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completion of this one!

Introduction to Fluids

Properties of All Fluids: •Direction of

Flow•Pressure•Expansion Principles

CORRECT! Dirt and all other

solids are NOT fluids

SORRY! Gases are

Fluids

SORRY! Liquids are

Fluids

Introduction to Fluids

Start: Section 1

Click on the picture that is not a fluid

A fluid is any material that flows and its shape changes

to that of its container.

•Direction of Flow

Start: Section 1

In what direction do all fluids flow, no matter if they

are liquids or gases?

A. Top to bottom (downward)

B. Bottom to top (upward)

C. High Pressure to Low Pressure

D. Low Pressure to High Pressure

The muscle (red) pushes up on the lungs and air goes out the mouth. There is less pressure outside the mouth than in the lungs that are getting squeezed by the muscle

This can be illustrated with balloons as well.

There is more pressure inside the balloon and as a result, if the balloons were to be

untied, all the air would shoot out!

•Pressure

Start: Section 1

…the amount of force exerted on a given area

(Pressure = Force / Area)

You can increase pressure 2 ways:

1. Push harder (more force)

2. Push with the same force but on a smaller area

Who is applying more pressure?Who is applying more pressure?

A man pushing on a 2 square meter box with a force of 4,000 N oror

A woman pushing on a 4 square meter box with a force of 4,000 N

•Expansion Principles

Start: Section 1

It possible to blow bubbles that are square.It possible to blow bubbles that are square.

True

FalseBalloons

and bubbles are always round because fluids expand with equal force in

all directionsForce

Introduction

Applications of Principle to: Airplanes

The Game of BaseballGolfRace CarsOther Examples….

Introduction

Start: Section 2

As the speed of a fluid increases, the As the speed of a fluid increases, the pressure decreasespressure decreases

Airplanes

Start: Section 2

Click on airplane to see side-views of the wings

Given the same size plane, which wing design would allow a plane to get

off the ground the fastest?

INCORRECT!!!

Correct!!! Click to see why?

As air hits the front of the wing, it splits. Some flows over the top & some flows underneath.

All the air comes off the back of the wing at the

same time!

The air going over the wing has to travel a longer distance, due to

the shape of the wing, so it travels faster.

Since the air going under the wing is going slower, there is

more pressure beneath the wing and this pressure lifts the plane

off the ground!

*Air**Air*

The Game of Baseball

Start: Section 2

What makes the ball curve when a pitcher throws it?

Click baseball for more

info.

The ball is spinning when it’s thrown (In this case, it’s spinning COUNTER-

CLOCKWISE)

THINK: Where is the air moving faster? Above or Below the ball?

Air is moving faster below the ball because the ball is spinning in the same direction the air is flowing

Since the air is moving faster below the ball, where is there more pressure on the ball?

Slower Moving Fluid = Higher Pressure

So…. There is more pressure pushing down on the top of the ball because the air

is moving slower there!!

Which way will the ball curve? Up or Down?

Golf

Start: Section 2

Why do golf balls fly so far through the air?

Click for close-up

view

It’s all about the DIMPLES!!DIMPLES!!

As the spinning ball travels through the air, some air dips in-and-out of the dimples, while

some air goes between the dimples

*Air*The air that goes in-and-out of the dimples has to travel farther, so it has to travel

faster as well

Faster Moving Air = Less Pressure

Basically, an area of low pressure surrounds the spinning ball and

since there is less pressure on the ball, it travels a longer distance

SORRY!SORRY!

SORRY!SORRY!

SORRY!SORRY!

Race Cars

Start: Section 2

Why do race cars have spoilers on rear of the car?

A. To make the car more aerodynamic

B. To relieve some pressure pushing down on the back tires

C. To add some pressure pushing down on the back tires

D. To slow the car down

Correct!!Correct!!

Click to

learn more

An airplane wing (side view)

A spoiler (side view) *Look at picture above

A spoiler is just an upside down wing. Air must go farther

underneath, so it must go faster as well, in order to come

off the back of the wing at the same time.

The air goes slower over the top of the spoiler, so there’s more

pressure above the spoiler.

This increased downward pressure holds the back

tires on the ground for better traction.

Other Examples….

Start: Section 2

Try these 3 activities on your own at home or school

Print the Activities 1 and 2 WorksheetsActivities 1 and 2 Worksheets off from the links provided below and complete before turning in

Activity #1

Hold 2 sheets of computer paper out in front of your mouth, 1 on

each side of your face about 4-6 inches apart and then blow hard

between them

Activity #2

Tie a string to a ping pong ball. Turn a faucet on high and hold the ball by the

end of the attached string in the running water

Activity #3

Select and complete one of the projects discussed at this link. Click to open and print off this sheet for your project

Introduction

Applications of Principle to: Hydraulics

Hydraulic Brakes

Introduction

Start: Section 3

A change in pressure at any point in an enclosed fluid will be transmitted

equally to all parts of that fluid

Hydraulics

Start: Section 3

…hydraulics are devices that use liquids to transmit pressure from one place to another.

* They use liquids because they can’t be compressed, squeezed into a smaller space.

Question #1:

Where will the water pressure increase more if the water pumping station increases the pressure by 20 Pascal. At the supermarket 1 block away or your house 1 mile away?

Both Places

The pressure is passed through the water line equally in all directions and all the way

along it.

Hydraulic Brakes

Start: Section 3

How do they work?

Brake Pedal

Small Piston

Tank of Hydraulic

Fluid

You push your foot gently on the brake pedal, which is connected to a very small

and easy-to-move piston

The small piston gets pushed forward causing a much larger piston to move as well, which forces liquid into a tiny hydraulic line

This tremendous liquid pressure is then exerted on the brake pad which moves up against the wheel, and stops it from turning

Liquids are used in hydraulics and not gases, because no matter how much pressure is in that tiny hydraulic line, the liquid will not

compress. It moves straight ahead and pushes the break pad against the wheel

Large Piston

Hydraulic LineBrake Pad

Because the line is so small, and so much liquid is being forced through it, the liquid has tremendous

pressure behind it

Introduction

What is Buoyancy? & The Science Behind Floating Objects!

Applications of Principle to:

Large Floating VesselsSubmarines

Introduction

Start: Section 4

The buoyant force on an object in a fluid is an upward force equal to the weight of the volume of fluid

that object displaces

THINK ABOUT IT THIS WAY:

The more water the object displaces, the more upward

(buoyant force) there is pushing up on the bottom of the object

What is Buoyancy? & The Science Behind Floating Objects!

Start: Section 4

Buoyancy is the upward force that fluids exert on objects, which aids

in making the objects float

The amount of upward force holding the object up

depends on how much water the object displaces (how

much water level rises)

If you put the 2 objects below in a bowl of water, which will make the water

level rise more?

CORRECT INCORRECT

…because the large gold box will displace more water, it will

have more buoyant force pushing up on it.

You may be thinking, that doesn’t make sense, because we all know big objects

usually sink? Click to learn more!

The Duck Floats & The Rock Sinks

* The rock is bigger so it has more buoyant force holding it up, yet it sinks. Why?

….because the science of floating involves buoyant force & WEIGHT!!

* Analyze the numbers. See if you can determine why the rock sinks. *

Weight of Rock = 40 N

Weight of Water Displaced = 30 N

Weight of Duck = 10 N

Weight of Water Displaced = 15 N

The buoyant force pushing up on the rock is only 30 N because that is how much water was displaced by it. The rock weighs 40

N. 30 N of force isn’t enough to hold up a 40 N object!

Large Floating Vessels

Start: Section 4

A ship is extremely heavy, but yet they float?

Ships are also very large in size! Why is that important?

A. Ships displace a lot of water

B. The weight is spread out over a larger area (Less Dense)

C. Both A & B

Almost!

Not Quite!

The heavier the ship, the larger in size it must be, so that it displaces more water. The water it

displaces must weigh more than the ship itself, so that the buoyant force is strong enough to hold the ship up. If it doesn’t displace enough

water, the ship will sink.

Submarines

Start: Section 4

Things such as: submarines, humans, and fish can float

and sink. How is this possible?

A submarine is hollow on the inside for the most part. (It is not very dense – the

weight is spread over a large area)

** Example **** Example **

Weight of Submarine = 20,000 N

Weight of Displaced Water = 21,000 N

Size of Submarine = 2,000 cubic feet

Will the submarine float?

It will float because the buoyant force (displaced amount) is more than the weight of the submarine!

What does a submarine do to make itself sink? Which

variable below can it change?

The submarine can’t shrink up so it displaces less water. But

it can increase in weight!!

A submarine has tanks that can fill up with water to make it

heavier so it sinks. In the case below the submarine would have to fill the tanks with

1,001 N of water or more to sink!

Content:Holt, Rinehart, & Winston,. (2002) Forces, motion, and energy. Eureka! A bat with dimples. (p. 58). Austin, TX: Harcourt Classroom Education Co.Holt, Rinehart, & Winston,. (2002) Forces, motion, and energy. Forces in fluids (pp. 68-81). Austin, TX: Harcourt Classroom Education Co.

Science Standards (Grade 8):D.8.5 While conducting investigations, explain the motion of objects by describing the forces acting on them

D.8.6 While conducting investigations, explain the motion of objects using concepts of speed, velocity, acceleration, friction, momentum, and changes over time, among others, and apply these concepts and explanations to real life situations outside of the classroom

Sound / Images:Callaway Golf Co. (2005). Retrieved November 12, 2005, from http://www.callawaygolf.com/en/default.aspxFogerty, J. (2005). Centerfield. The Long Road Home [CD]. Beverly Hills:

Concord Music Group. Indy Racing League. (2005). Indycar series. Retrieved November 12,

2005, from http://indyracing.com/home.phpMitchell, M,. (2003). Animated demonstration of Bernoulli’s principle. Retrieved November 12, 2005, from http://home.earthlink.net/~mmc1919/venturi.htmlRawlings Corp. (n.d.). Retrieved November 12, 2005, from http://www.rawlings.com/Rolling Greens Stock Agency & Golf Photography. (1998). Retrieved

November 12, 2005, from http://www.rollinggreens.com/ Default.htmStorm, R,. (n.d.). Glenn Learning Technologies Project: Ping pong ball

curves. Retrieved November 12, 2005, from http://www.grc.nasa.gov/ WWW/K-12/TRC/ Aeronautics/ Ping_Pong_Curve.htmlThe Boeing Company. (n.d.). Retrieved November 12, 2005, from http://www.boeing.com/flash.html