Fluids

BELLWORK : What does it mean to be fluid?

Bellwork – 01/27/14

• On ice and it starts to crack – what do you do?

Bellwork – 01/27/14

• On ice and it starts to crack – what do you do?

– Lay down flat

– Distributes weight over more surface area

BELLWORK - Pressure

• What is pressure?

BELLWORK - Pressure• What is pressure?

• Feeling forced to do something

• A force needed to squash an object

• Force exerted per unit area of a surface

TN Standards

CLE.3202.1.8 – Investigate relationships among the pressure, temperature, and volume of gases / liquidsCLE.3202.Inq.3 – Use appropriate tools and technology to collect precise and accurate dataCLE.3202.Inq.6 – Communicate and defend scientific findings

PhET simulation

• Heat water to steam ( turn heat up at bottom )

• What happened to pressure in a closed container?

• So why does the container ‘splode??

Balloons

• While it is running, we’ll use balloons as an example of pressure

• How does amount of gas in balloon relate to its size?

Balloons

• What direction is the gas inside the balloon pointing to?

Balloons

• What direction is the gas inside the balloon pointing to if really hot?

Balloons

• What can we say about the pressure found in balloons of different sizes? ( start out the same size )

– Small one– Big one

Balloons

• What can we say about the pressure found in balloons of different sizes? ( start out the same size )

– Small one– Big one

PRESSURE IS LARGER IN THE BIGGER ONE

Challenge

• What is a possible mathematical relationship for pressure?

• Force and surface area are involved

• What are independent and dependent variables?

Pressure

• Force exerted per unit area of a surface

• Pressure = F / A ( force divided by area )

Pressure - Example• Write down or Estimate your weight in lbs :– 190 lbs

• Estimate the area of your shoe-sole ( in2 ):

• Mine – 4.25 “ wide & 12 “ long• Shoe area = 51 x 2 = 102 in2

• Pressure when standing on floor equals:– Weight / total shoe-area– 1.9 psi exerted on floor

Take Home

• Force is directly proportional and surface area of ( contact ) is inversely proportional to pressure

• P = F / A

• Increase force increase pressure• Increase area DECREASE pressure

Buoyant Force• A buoyant force pushes the boat up

• All fluids exert an upward buoyant force on matter

Work with Partners

• Study Guides

• Pg 12

• #2, 3 ( put in N / cm2 )

Challenge / Exit Pass

• Consider a submarine at the bottom of the ocean.

• What is the water doing to the submarine

• Why does the submarine not get crushed?

PLC Day / Upcoming in Week

• Gonna watch stuff ‘splode ??

• Open-Notes Quiz Thursday/Friday

Exit Pass