Physical Science
Period:
Name:
Paper Towel Lab
Date:
All answers (other than numbers in the data table) should be in complete sentences!!
Lab problem: We will be testing and comparing the absorbency of various brands of paper towels
Pre-lab
1. What is the precision to which we will measure our water, assuming that the graduated cylinders have
1ml divisions? Why is that?
We can measure to one more level of precision, since the
measurements are in 1 ml, we can estimate to the 0.1 ml
2. Given what you said above, give the volume of water in the graduated
cylinder to the left to the correct level of precision:
The measurement is approximately 52.7ml.
3. What is your hypothesis about which brand will be the best and why?
Any hypothesis stating what paper towel brand
would be the most absorbent and why you
thought that
4. What is the manipulated variable in our experiment, and how do you know?
The manipulated variable is the brand or type of paper
towels, because that’s the variable we are changing.
5. What is the responding variable in our experiment, and how do you know?
The responding variable is how much water is absorbed,
because that’s what we’re measuring in response to the
change in type of towel.
6. List 4 controlled variables (there are way more than 4 possible) and what numbers or methods would
you choose for each (we will decide on values to use as a class later).
Variable (or description of controlled variable)
Value or method
1.
2.
3.
Any 4 variables that
need to stay the same
between trials to ensure
a fair comparison
4.
Why is it important to control these variables?
with
4
corresponding
values/methods
If we don’t keep these values the same between all tests,
our test’s validity is gone, and we don’t have a fair
comparison between trials.
Class controlled variable values discussion:
Period 1
7. Listen to the class discussion about the controlled variables. For the controlled variables, what
did we decide to use as values in this class?
Variable (or description of controlled variable)
Value or method
1.
2.
3.
4.
5.
6.
7.
8.
9.
Class controlled variable values discussion:
7. Listen to the class discussion about the controlled variables. For the controlled variables, what
did we decide to use as values in this class?
Variable (or description of controlled variable)
1.
2.
3.
4.
5.
6.
7.
8.
9.
Value or method
Class controlled variable values discussion:
7. Listen to the class discussion about the controlled variables. For the controlled variables, what
did we decide to use as values in this class?
Variable (or description of controlled variable)
Value or method
1.
2.
3.
4.
5.
6.
7.
8.
9.
Class controlled variable values discussion:
1. Listen to the class discussion about the controlled variables. For the controlled variables, what
did we decide to use as values in this class?
Variable (or description of controlled variable)
1. Amount of time to absorb water
2.
What kind of surface or method
Value or method
10s
Put in 400ml beacker
3. Amount paper towel used
20.5 x 15.5 cm
4. Starting volume of water
40 m
5. How it gets water
put in beaker
6. How paper
towel is
folded/wadded
fold in ½ 4
times, push with
pencil
7.
8.
Data table. Make sure you express your data to the level of precision specified
Final Volume left in beaker(ml)
Initial
Volume in
Average of
Brand
Trial 1
Trial 2
Trial 3
beaker (ml)
trials
Average ml absorbed by the
paper towels (show your work)
BHS
Bounty
Brawny
Brightly
Kirkland
Pantry
Essentials
Sparkle
Thirsty
Viva
Data table completed with:
 At least 1 trial for each paper towel type
 Average
 Amount absorbed, with work shown, for each and
values
 All measured data recorded to a precision of 0.1ml.
Analysis: make a graph (of the appropriate type) comparing the average amount of water absorbed for the
different brands of paper towels. Include all the qualities of a good graph. Make sure axes are in standard order
Bar graph
Meaningful Title
Manipulated variable on x-axis  paper towel brands
axes labeled :
x  paper towel brands
y  water absorbed (ml)
even increments on axes
be large enough to be seen about at least ½ space allotted
drawn using a straight edge
Conclusions: Answer in complete sentences.
1) Which type of paper towel actually absorbed the most water? How did this compare to your original
hypothesis?
Described which paper towel absorbed the most water
and how that compared to your predictions in complete
sentences.
2) What are some other factors besides absorbency that are important when considering a particular paper
towel brand?
At least two other factors (e.g. Strength of the paper
towel while wet, speed in absorbing water, durability
of the paper towel when rubbed, number of paper
towels per roll, etc.)
3) Choose one of the factors you listed in conclusion question #2, determine how you would test it, specifically
mentioning what your manipulated, responding, 4 controlled variables would be, as well as a brief process
to test it.
Item from conclusion question 2 you’re testing:
listed here
type of towel ;Responding variable: item listed in #2
Manipulated variable:
Any 4 controls
Cannot be brand
Controlled variables:
or responding var
process to test:
List of steps
4) The cost of the paper towels (when bought in bulk of 6 or more rolls) is as shown below.
Brand
Plain (BHS)
Bounty
Brawny
Brightly
Kirkland
Pantry Ess.
Sparkle
Thirsty
Viva
Price per
roll (in
bulk if
available)
$7.19
$1.24
$1.33
$0.83
$1.41
$0.99
$1.27
$0.92
$1.40
Approximate
number of
same-sized
towels per role
600
66
70
52
80
60
65
70
44
Approximate
cost of each
same-sized
paper towel
1.18¢
1.87¢
1.90¢
1.60¢
1.77¢
1.65¢
1.95¢
1.31¢
3.12¢
Using your data and the information to the
left, does the cost of the paper towels
directly correlate to the absorbency (is the
most expensive the most absorbent, 2nd
most expensive the 2nd most absorbent,
etc.), if not what relationship is there, if any?
Typically there is no
real relationship, as
Viva are the most
expensive per paper
towel and might absorb
the most water, and BHS paper towels are the cheapest per
paper towel and do absorb the least, but the rest are
relatively random
Ranking by price and absorbency would be:
$
Per 1
Per 3
Per 5
Per 6
BHS
Thirsty
Brightly
Pantry
Kirkland
Bounty
Brawny
Sparkle
Viva
BHS
Pantry Ess.
Sparkle
Brightly
Thirsty
Viva
Kirkland
Brawny
Bounty
BHS
Pantry Ess.
Brightly
Sparkle
Kirkland
Thirsty
Brawny
Bounty
Viva
BHS
Pantry Ess.
Brightly
Sparkle
Brawny
Thirsty
Kirkland
Viva
Bounty
BHS
Pantry Ess.
Sparkle
Brightly
Thirsty
Kirkland
Brawny
Bounty
Viva
5) Using the information given in question 4 and your own data, divide the average ml absorbed by cost per
towel to get ml absorbency for each cent of cost, this will give the ratio of absorbency to price for each of
the brands. Summarize calculations in the table below (Show your work!!):
BHS
Bounty
Brawny
Brightly
Kirkland
Thirsty
Pantry
Essentials
Sparkle
Viva
Absorbency
for each cent
of cost
(Show work)
Which paper towel has the most absorbency for each cent of cost? What does that mean?
The paper towel with the most absorbency for each cent of
cost is Thirsty which means it absorbs the most for its cost
(most worth the money, if absorbency is primary factor for
buying)
6) Why might the school use the plain white towels rolls instead of another brand? Hint, look at the tables you
generated above as well as other tables given to you in conclusion question 4. Give at least two different
ideas.
The school uses the white paper towels because
 They are the cheapest overall per towel, so are most
cost effective
 They have the most (by far) number of paper towels
per roll so they don’t have to be replaced very often
and will last way longer than other paper towels,
saving man power needed to change more often.
 Their absorbency per cent of cost is actually on par
with or better than some of the name brands.
 They fit into the standard, lockable dispensers, so they
can be more easily regulated.
 They are thinner and take up less landfill space.