Breath volume and measurements of length, area, volume and mass
Created by Dr.Walt Volland, All rights reserved copyright 1998-2005
revised by Dr. Walt Volland March 25, 2005
| You need to post your average personal breath volume early enough so that a class average can be figured from Breath Volume postings in the Breath Volume forum . Your lab report for Dr. Walt Volland's class is completed when you submit your equiz 2 in Blackboard. |
Measurements
are a fundamental part of science and technology. The way
measurements are made is always on a relative basis. The
medieval systems were typically established by royal decree
and often referred to the dimensions of body parts. A time
line for refinements in the definition of the meter is
at
http://www.mel.nist.gov/div821/museum/timeline.htm
Another
time line is at
http://lamar.ColoState.edu/~hillger/meter.htm
|
This web site is a source of conversion factors |
http://www.soton.ac.uk/~scp93ch/units/convfact.html
| Units and conversion factors are described and illustrated at these sites |
http://ull.chemistry.uakron.edu/genobc/Chapter_01/
http://www.wsdot.wa.gov/Metrics/factors.htm
This experiment
is intended to give you hands on practice with length, area, volume
and mass units. You will use the SI units to measure length. You will
measure length and width and then calculate area. You will construct
a cube with each edge equal to one decimeter to see first hand how the
volume of a liter is defined. You will also measure out a liter of water
and "feel" the heft of a kilogram. Since water has an approximate density
of 1 gram /mL, the mass of the liter of water is essentially 1 kilogram. The actual volume
of a container like 2-liter soft drink bottles or 1 gallon plastic jug
will be measured. The 2-liter bottle (you may need two of them) or plastic
jug will then be used to measure the volume of your exhaled breath.
The displacement of water from the container can be done in a sink,
but some folks have suggested using a bath tub. I worry about people
falling into the tub. You will repeat this measurement three times and
report your average value. If you are in Dr. Walt Volland's class post
your results in the subject line. Please use the format like this example
Duck, Donald -250 mL , Post the message in the class forum in Blackboard
under communications at Breath
volume forum You will also compare
your average value with what your classmates report. You will give reasons
why youbelieve there are variations from person to person. You will
also make suggestions for possible improvements in the procedure.
Supplies
and Materials
Flexible plastic
straw or plastic rubber tubing (available from pet stores, Lowes, Home
Depot, etc) Ruler with metric
scale showing centimeters and millimeters Measuring cup able
to measure milliliters (Pyrex and other "glass" types usually have both
metric and American units) Two empty, clean
plastic 2-liter soft drink bottles (2) or one 1 gallon plastic jug.
Large bowl, kettle,
pail or other container, approximately 8-10 qt. or larger ( sink or
bath tub?)
READ ALL THE STEPS IN THE PROCEDURE BEFORE STARTING THE EXPERIMENT
Length and area
Use the centimeter
ruler to measure the length and width of the first page of your textbook
in units of centimeters. This page has a list of the element names,
symbols and average atomic masses. Record the length and width on the
report sheet. Calculate the area
for the page to the correct number of significant figures. Record your
answer, including the proper units. Convert your area
to square millimeters and record your answer. Do the number of significant
figures change?
Volume and the decimeter
Use your centimeter
ruler to draw a line 10 centimeter long. Draw another 10
cm line at a 90 degree angle to the first. Draw two more lines
in the same way so you have constructed a square with 10 cm edges. Make a mark 1 cm
to the left of the lower right hand corner; make a similar mark 1 cm
above the lower right corner. Draw lines 1 cm long perpendicular (at
90 degrees) to the lower and the right edges of your square so you have
drawn a small square 1 cm on an edge. Repeat steps 1-4
to make five more squares just like Side 1. Cut out the 6 squares
and tape them together to form a cube. Place the little squares at the
lower right corner in front and at the upper left rear corner of this
cube. The big cube you
have built is a cubic decimeter in size. It has a volume of one liter. What is the volume
of the little cube whose faces you see in the lower right corner of
the big cube? How many of these little cubes fit into the cubic decimeter?
--------------- ------
------------------ ------ ------ ------ ------ ------ ------
------ Remember that when
length is multiplied by length the new units are length to the power
of "2". The unit label has an exponent of "2". This is because
the units are squared. Area =
centimeters1 x centimeters1 = centimeters2
= cm2 example:
3.4 cm1 x 2.0 cm1 = 6.8 cm2 conversion
to mm2 requires the following 6.8 cm2
x 10 mm/ cm x 10 mm/cm = 680 mm2
Remember
that when length is multiplied by length is multiplied by
length the new units are length to the power of "3". The
units are cubed. Volume
= centimeters1 x centimeters1 x centimeters1
= centimeters3 = cm3 example:
3.4 cm1 x 2.0 cm1 x 5.0 cm1
= 34. cm3
Mass of one kilogram
Gather the bottles
whose volumes you will measure, and your measuring cup with milliliter
calibrations. Be sure your bottles
are clean and dry. Pick up the empty bottle and get a sense of its weight. Use your measuring
cup to add one liter of water to the bottle. Mark the water level with
a marking pen. Lift the bottle and its contents. Note the "heft" of
the bottle and water. This mass equals a kilogram plus the mass of the
bottle. Hopefully this gives you a feeling for a kilogram.
The volume of a breath of exhaled air
Gather the 2-liter
bottles or gallon jug, measuring cup, large container, and a flexible
straw (18 inches of plastic or rubber tubing available from Petco fish
department, Lowe's or Home Depot may be used instead of a straw). Fill the bottles
to the very top with tap water. Carefully pour water from the bottle
into the measuring cup to determine the volume of water in milliliters
that actually fits into the bottle. You will need to transfer a number
of portions of water to the measuring cup. Be sure not to fill the cup
above its top reference mark. Keep track of the amount of water you
pour into the cup. Record the bottle's volume in milliliters to the
correct number of significant figures. The bottle will hold more than
two liters. NOTE more than one bottle may be needed to collect all of
your breath. Repeat
this step two more times. Then average the 3 values for the
volume of your bottle and record the average. Place
the kettle or other large container in the kitchen sink. Add
tap water to this container until it is about half
full. Fill
your 2-liter bottles again to the very top. You can seal the
bottle by screwing the bottle cap on. Alternately you can
place the palm of your hand over the mouth of the bottle to
seal the bottle, but it is more difficult to keep the water
in the bottle this way. Keep your hand tight against the
mouth of the bottle and turn the bottle upside down. The
water should still be in the bottle because you have the
mouth sealed with your hand. If you screwed the cap on the
bottle simply keep the cap on until you are ready to blow
into it. Keeping the bottle
upside down, carefully put the mouth of the bottle a feel inches below
the surface of the water in the large container. You can unscrew the
bottle cap to open the bottle. You can then remove your hand from the
mouth of the bottle. The water should stay in the bottle as long as
the mouth of the bottle stays underwater. Take your flexible
straw and bend it to make a "3" shape. The type of straw is shown here.
You will need to adjust the bend to suit your work. The coin (a penny)
is included to give an idea of the relative size of the straw. Flexible
rubber or plastic tubing simplifies this step. Put
the short end inside the mouth of the bottle. You should be
able to put your mouth on the other end. Before
you put your mouth to the straw, take a deep breath and hold
it. Close
your lips around the straw and blow out as much air as you
can in a steady stream through the straw. Air bubbles will
come out the end of the straw and be trapped in the bottle
as you exhale. The air will push an equal volume of water
out of the bottle, which is why you have your large
container sitting in the sink! While
the mouth of the bottle is still underwater, place the palm
of your hand over the mouth to again seal it. Keep the
bottle sealed with your hand. Remove the bottle from the
container and turn the bottle right side up. Measure
the volume of water left in the bottle by pouring the water
into your measuring cup as you did before. Record this
volume in milliliters. Calculate
the volume of your breath by subtracting the volume of the
water left in the bottle from the total volume of the
bottle. Record the volume of breath you can
exhale. Repeat
until you have three measurements of the volume of breath
you can exhale. Calculate
the average volume you can exhale and post your result to
the class conference.
Report sheet for data, results, and answers to questions.
The experiment report for Dr. Volland's class is due midnight of the designated Monday
Use the lab results to complete your equiz 2
1.
Length and area Report data with
appropriate number of significant figures 1. What is the long
dimension of the textbook page in centimeters? cm. 2. What is the narrow
dimension of the textbook page in centimeters? cm. 3. What is the area
of a page in square centimeters? set up for calculation
below and the answer with units in the box to the right. 4. What is the area
of a page in square millimeters? set up for calculation
below and the answer in the box to the right.(This is a second order
conversion, exponent is a "2" not a "1" on the units.) mm2 2.
Volume and the decimeter When you constructed
your cubic decimeter, you were to mark the outline of a smaller cube
on the lower right hand corner. What is the volume of the little cube? How many of
these little cubes will fit into the cubic decimeter? Show any calculations
to support your answer here.
3.
Mass of one kilogram. Does the "heft"
or heaviness of the mass of a kilogram surprise you? Briefly explain
your answer. Name any object
that you handle regularly that has a similar mass and "heft".
4.
The volume of a breath of exhaled air by difference between water needed
to fill bottle and water remaining. Volume of water
in milliliters (m L) to fill bottle to its top Trial 1 Trial 2 Trial 3 Average volume
of water held by bottle
Volume
of water left in the bottle after exhaling into bottle. Trial 1 Trial 2 Trial 3 Average volume
of water left in bottle
Volume of your
breath calculated by subtracting the average volume of the water left
in the bottle from the average total volume of the bottle. Show calculation.
NOTE more than one bottle may be needed to collect all of your breath. breath volume = volume
held by bottle - volume water left in bottle. Example for three
trials Record the volume
of breath you can exhale below. Post your breath volume with your name
and average volume in mL in the
subject line
at the appropriate forum for your class section. Post your average volume
of breath in mL in the following format Clinton, Hillary-2300
ml Lincoln, Abraham-3400
ml Duck, Donald-1100
ml Duck, Daffy-1400
ml This allows people
to see the value without opening the message and saves time. Use the Breath
volume forum part of the communications area for WAOL Blackboard. The
current forum is titled Use
five values posted by the other members of the class to calculate
the average breath volume for the class in mL. Show the values you
used to calculate your average. Report the average to the proper number
of significant figures. Please
do not give 8 digits just
because your calculator generates them. Round
off to the appropriate average. Example:
1100 mL + 1560 mL + 1930 mL = 4590 mL total The
average volume is 1530 mL which should be rounded off to 1500 mL .
There is a consistent value in the "thousands" place. Variations begin
in the "hundreds" place. This has only two significant figures. The
uncertainty or variation starts in the hundreds place. All the digits
in the "ones" and "tens" places are not meaningful
and need to be dropped
container
volume
volume of water left
breath
volume in ml
Trial
1
2200
ml -
100
ml
=
2100 ml
Trial
2
2200
ml -
300 ml
=
1900 ml
Trial
3
2200
ml -
220
ml
=
1980 ml
Average
=
2060 ml
2100
ml rounded to two sf
Student 1 Student 2 Student 3 Student 4 Student 5 Class average
breathe volume for six class readings in mL mL
What is the difference
between the class average(five values and your measured volume. Give
difference in milliliters and liters. difference in milliliters difference in liters. What are these differences
as a percent of your volume? Remember percent
= 100 x ( difference in volumes / average volume) Does the percent
difference change when you change units? Show your set up
for calculations.
Give a suggestion
on how you think the experiment could be improved. Identify some aspect
you liked about the experiment. Identify something
in the experiment that was new to you.
revised by Dr. Walt Volland March 25, 2005
The experiment report is due for midnight of the designated Monday