Physics Laboratory 1

The laboratory exercises are not just about getting the right result, but about recognizing that fundamental physics principles shape your everyday experiences and underlie many of the devices that you will use in their personal and professional life.

Please do not treat the laboratories as cookbook exercises.  Permit yourself to think!  Thoughtful answers to the questions in blue will give you most of the laboratory credit.


Objective:

In this laboratory you will first investigate properties of fluid      pressure.  You will then determine the density of a metal block by applying Archimedes' principle.  You will also explore some of the consequences of the equation of continuity and Bernoulli's equation.

Open a Microsoft Word document to keep a log of your experimental procedures and your results.  This log will form the basis of your lab report.  Address the points highlighted in blue.  Answer all questions.

Exploration:

Open the simulation Under Pressure.

The interface

Explore how the pressure in the liquid changes as a function of depth, liquid density, filling level, and external conditions.  Answer the questions below, always supporting your answer with data from a measurement.

Experiment: 

Archimedes' Principle states that an object partially or wholly immersed in a gas or liquid is acted upon by an upward buoyant force B equal to the weight w of the gas or liquid it displaces.  In this experiment you will verify this by measuring the apparent loss of weight of several submerged objects and by finding the weight of the displaced fluid.  You will also determine the density of the objects.  A PASCO Force Sensor is used to measure the weights.

Equipment that was used to produce the experimental data below:

image

Procedure:

Verify Archimedes' principle using the data below.  Click on a small picture if you want to see an enlarged picture.

(a) (b) (c) (d)
Object 1: image image image image
Object 2: image image image image
Object 3: image image image image
Object 4: image image image image

For each of the objects:

(a)  Determine the weight Wc of the empty container with the handle.  When the container is suspended from the force sensor, the force sensor measures the force of gravity (weight) acting on the object, and the program displays the magnitude of this force (in N) on the computer screen.

(b)  Determine the weight of an object Wo when it is suspended above the container with the overflow spout.  This container is completely filled with water, and the container with the handle standing below the spout is empty.

(c)  Determine the apparent weight of the object Wow after it has been lowered into the water.  As the object is lowered into the water, water pours out of the overflow spout.  The container with the handle has collected this water.

(d)  Determine the weight Wcw of the container with the handle holding the collected water.

Record the weights in a spreadsheet as shown below.

  Wc Wo Wow Wcw Ww Fb (Fb-Ww)/Fb
Object 1              
Object 2              
Object 3              
Object 4              

For each of the objects:

Determine the density of the objects used in part I.

Extend your Excel spreadsheet.  Set up labels as shown below.

  mo mw Vw ρo material
Object 1          
Object 2          
Object 3          
Object 4          
Material Density (kg/m3)
Aluminum   2.7*103
Brass 8.7*103
Lead 11.3*103
Steel 7.9*103
Water 1.0*103

Log entries:


Exercise: 

Do the following exercises and add answers to the questions in blue to your Word document.

(a)  Lay your hands on the table in front of you and locate a bulging vein.  Slowly raise your hand until it is well above your head while constantly watching that vein.  What happens?  What height above your shoulders do you first notice a change?  Describe your observations.
Slowly lower your hand while still watching the vein.  Repeat the process.  Do you have an explanation for your observations?

(b)  Lay two thick books about 10 cm apart.  Place a sheet of paper on the books so that it bridges the gap between them.  Try to blow the paper off the books by blowing underneath it.  Describe what happens.  Do you have an explanation for your observations?

(c)  Hold two sheets of paper vertically about 5 cm apart.  Blow the sheets apart by blowing hard between them.  Describe what happens.  Do you have an explanation for your observations?

image(d)  Cut a drinking straw into roughly two equal length pieces.  Hold one piece upright in a glass of water so that the top projects over the top of the glass.  Place the second piece perpendicular to the first so that the end of the second piece is almost touching the opening of the first, but is not blocking it.  Blow hard through the second piece.  Describe what happens.  Do you have an explanation for your observations?


Convert your log into a lab report.

Name:
E-mail address:

Laboratory 1 Report

Save your Word document (your name_lab1.docx), go to Canvas, Assignments, Lab 1, and submit your document.