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Diaper Lab Handout
BRING THIS PROCEDURE TO LAB! (-5 if you don’t)
Disposable Diapers—Just How Absorbent Are They?
Lab Report Due: _______________
Do all questions/requirement
through the end of page 6!
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You can use the following text to help write your INTRODUCTION in your Lab Report (this section is
optional for non-advanced chemistry classes, but you will get extra credit (5 points) for doing a
good job). The introduction discusses a little bit of the chemistry behind the actual experiment. In
this experiment we are using a polymer (go back to your notes from Chapter 1 where we discussed
polymers) to absorb liquid. Disposable diapers are mostly just made from plastic. Would you grab
a plastic bag to wipe up a spill of water or your drink? Of course not, because plastic (a man-made,
organic polymer made from petroleum products) won’t absorb the liquid. Because it would be
gross for diapers to not absorb “the liquid” coming out of a baby while he/she is wearing it,
chemistry is used to solve the problem.
Molecules are either hydrophilic (loves water) or hydrophobic (hates water). This is all governed by
forces that exist between molecules, and as you might expect, electrons are going to have a lot to
do with this (as a matter of fact, interactions between electrons is pretty much what Chemistry is).
We’ll learn more about these specific forces in Chapter 8.
Huggies are the number 1 selling brand of diapers in the country. Some of you probably wore them
at one time in your life. Disposable diapers are more convenient, and are supposed to be very
absorbent. But, how absorbent? How many times their weight can the diapers hold? Since we are
all scientists in room 225, let’s find out. Use this page to help write the introduction?
Diapers contain a chemical called sodium polyacrylate. It is a polymer, meaning that it consists of
chains of identical units (monomers). The monomer for sodium polyacrylate is:
—CH2—CH(CO2Na)—
It is a pretty cool polymer. Not only do they form chains, but the chains can also link to other
chains. We call these “cross-linkages.” When this happens, they actually start to build in some
pockets of air within the structure of the polymer.
When you put sodium acrylate in water, osmosis causes the water to absorb into the polymer,
because there is a higher concentration of water OUTSIDE the polymer than INSIDE it. Does that
make sense? Try to remember this in terms of cell biology from last year.
How much water can they absorb? Well, we’re going to find out. But that’s not all, because babies
don’t put just water into them. Urine is a bodily fluid that is mostly water, but contains some salt
and other minerals (urine is about 2.2% salt). Your blood has salt in it too. As a matter of fact, if
you go to the hospital, sometimes they will give you an IV (intravenous) of normal saline solution by
sticking a needle directly into your vein in your arm, which is 0.9% salt.
Due to OSHA regulations regarding the handling of toxic biological waste (and just general good
taste), we’re not going there. We’re going to figure out much water the diaper absorbs by
measuring out 100 mL at a time (accurately, using a graduated cylinder).
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Procedure:
1. You are going to work in groups at your table. Each group will get 1 diaper. Write down
your partners names so you don’t forget them. You may not switch to another group to
work with friends. You will use either a Huggies or Pampers diaper.
2. Prior to beginning any work, you needs to come up with a hypothesis. Hypotheses do not
always need to be in “if-then-because” format, but it is a good idea. Not all “if-then”
statements are good hypotheses, however. In this case, you’re simply going to make a
prediction, in milliliters, of how much you think the diaper will hold.
3. Look at the graduated cylinder. Look at the diaper. How much water, in milliliters, do
you think it will hold. You should write: My prediction is that the diaper will hold X mL of
water. X is your guess, obviously. You do not all have to have the same hypothesis, but
you can.
4. Each group needs a Styrofoam cup, a scoopula, a large tray, a beaker and a 100 mL
graduated cylinder.
5. Weigh your diaper prior to doing anything else. Record the mass in grams. Grams are
abbreviated with a little “g,” so if your diaper weighs 30.00 grams, record it as 30.00g.
6. Unfold your diaper. There is a cotton strip in the middle. You need to get this out without
ripping it. Mr. Schwartz will walk you through the procedure. If you destroy your diaper, I
do not have extras. Be careful!
7. Weigh the empty cup. Record the mass of the empty cup in grams.
8. Put the cotton strip into the cup AND all the powder and weigh it again. Record the mass
of the full cup in grams.
9. Pour the contents of the cup into the large tray. Using your graduated cylinder, measure
out water in 100mL amounts and pour it onto the cotton strip. Make observations as to
what happens. Make sure to read the graduated cylinder at the “meniscus.” If you don’t
know what that is, ask me. Keep track of the total volume of water you use.
10. Check to see if all the water has been absorbed by tilting the tray. ONLY use the graduated
cylinder to measure; do not measure with the beaker. You can use the beaker to refill the
cylinder; it’s easier than the sink. But, we do not measure out volumes using a beaker.
11. SAFETY HAZARD: Sodium polyacrylate is moderately toxic if you swallow it. Keep it out
of your eyes. The best way to do that is to WEAR YOUR GOGGLES. Don’t try to breathe it
in, but it is relatively harmless if you do. If you get some on your skin, wash with soap
and water immediately. Clean up any spills with water.
12. When you are done, compare how much stuff there is to when you started. Make an
observation. Dump the contents of your tray into the trash bags to clean up. Rinse the
tray out with some water and dry with a paper towel. Do NOT dump anything down the
drain.
13. This is all you need to read for now. You can read the rest later. Get your data sheet, on
the next page, and begin working once your group is ready.
Data sheet on the back of this page!!
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Data Sheet: Use this section to record your data. Recreate this table INTO your lab notebook to
record your data and observations (which are also data—qualitative data). Use all your senses to
make observations (just don’t taste anything).
Partners Names:
Hypothesis:
Data
Observations (you won’t have an
observation at each step, but when you
do, write it down in this column).
Mass of Diaper
Mass of Cup
Mass of Cup + Cotton Strip
Mass of Cotton Strip
Volume of Water Used (keep
track!!!)
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Analysis of Data: (you can do this section at home, when you write the lab report)
1. The density of water is 1.00 g/mL . Density = mass / volume. You know the volume of
water you used. Calculate the mass of water you used.
2. Calculate the percent mass absorbed by using the following formula:
(Mass of Water from “1” above) / (Mass of Cotton Strip) x 100
3. Calculate the absorbency of the diaper by using the following formula:
(Mass of Water from “1” above) / (Mass of Diaper)
4. What is the % error in your hypothesis. Use the following formula:
Amount of Water Used – Your Predicted Amount
Your Predicted Amount
X 100
If you made any errors that you know affected your results, always discuss them in the analysis of
data section. The lab report is not the place to “lie” about what you did. You will never lose points
on your lab for honestly discussing a mistake or a procedural error and giving me your best guess as
to how that affected your results.
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Questions (answer these in your lab report; include in the Analysis of Data section)
1. Huggies, size 4, fits babies who are 22-37 pounds. If 1 kilogram (kg) = 2.2 pounds, what is
the range of masses in kilograms (in other words, what is 22 pounds in kg? What is 37
pounds in kg? What does range mean? You need to do some calculations to answer this.)
2. Do some internet research on polymers. Write at least 1 paragraph to tell me what you
found out (Schwartz’s definition of paragraph: 5 complete sentences minimum).
3. Urine is actually at normal body temperature, which is 37C. Do you think that urine would
absorb any differently than water did? Why or why not?
4. The water we used was room temperature. What was the room temperature in C? Do
you think the water would absorb any differently at normal body temperature? Why or
why not?
5. Did you think this was a fun lab? Yes or no answers are not sufficient. Tell me why or why
not in complete sentences. How would you make it better for next year’s class? (This
question should be a paragraph. Schwartz’s definition of paragraph = 5 complete and
well-written sentences.)
Some students “accidentally” forget to answer the questions. Don’t!! For this lab, these questions
are worth 20 points!
CONCLUSIONS:
You need to write up a conclusion for your experiment. A conclusion summarizes what was learned
in your experiment. A conclusion is NOT what was DONE. That’s what the “procedure” is for.
If you have made any new or ground-breaking discoveries, here is where you will discuss them.
That’s not likely every time, but you just never know.
The conclusion section is also an appropriate place to discuss how you could improve upon the
experiment if you were to do it another time. That would be improving the given procedure, not
necessarily just correcting and eliminating mistakes that your group made.
A conclusion in one experiment, for a scientist doing research, will often suggest a hypothesis for
the next experiment. If you think of a fun way to extend the experiment, or to have a “follow-up”
to investigate something else, be sure to discuss that.
You need at least a paragraph for your conclusion. There is a mandatory deduction of 5 points for
a “one sentence conclusion.”
END OF DIAPER LAB PROCEDURE; THE REST IS FOR WRITING UP
YOUR LAB REPORT!
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LAB REPORT FORMAT (Tape this page into lab
notebook in back for reference; rubric on back)
Title: (make it creative!). You will write….Title: This is the Title I Gave My Lab Report.
Date: (the date you ACTUALLY DID the experiment, not the date you write it up)
Partners: (so I can compare work…please do not copy from each other)
Purpose: (one sentence is fine)
Introduction: talk about the Chemistry involved in the experiment. The introduction MUST BE a
full page (at least) in your lab notebook. I will take off points for insufficient length. You might
need to actually do some research to write this. Use the information on the first page to help you
write an introduction for this lab. [Note for regular Chemistry students: you may omit this section
from your lab report, but if you do it, I will give you extra credit.]
Hypothesis: (try to write this BEFORE you do your experiments; a hypothesis is a testable
statement which is your best educated guess of your expected results. Use the “duh” test…if you
read your statement and think, “duh,” it’s probably not a good hypothesis. If you write the
hypothesis AFTER you have done the experiment and you know what is going to happen, that’s
NOT really a hypothesis, is it?)
Procedure: (written in bullet point or outline format, in enough detail so that I can re-do your
experiment just from your lab report, if I wanted to do so; include any necessary materials in your
description). Cutting out my procedure and taping it into your lab notebook is NOT acceptable
and you will lose points for doing that…-5 deduction)
Data: (quantitative and qualitative) Data tables are a good way to organize your data. Do not
forget observations. Those are data too!
Analysis of Data: (number crunching, reporting of final answers, sample calculations showing me
the formulas you used, etc; discussion of errors made and how they may have impacted your
results; if there are any “questions” assigned, the answers should be in the analysis of data section).
Conclusion: (at least a paragraph, but more if necessary; NO ONE-SENTENCE CONCLUSIONS!) I
take off points for a one-sentence conclusion!!
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REMEMBER for all lab reports for my class: PROCESS VS PRODUCT!
I really am interested in the process that you go through. I could not care less if your hypothesis
was proven true or proven false. What I am interested in is seeing you analyze your results,
provide some logical and scientific basis for your results, and honestly discuss your errors as
“reasons” for why your experiment might not have worked as well as you hoped. Your lab report
should be written neatly and legibly. It should be written in pen (if you started in pencil, don’t
worry, just change to pen, but if you write the entire report in pencil, that’s a 10 point
deduction). Do not erase or tear out anything from your lab notebook, ever. Just draw a line (or
X) through it, put an explanation if necessary.
Tentative Grading Rubric (subject to change based on requirements of lab).
Element in Report
Chemistry
Advanced Chemistry
Title
-2 if missing
-2 if missing
Date
-1 if missing
-1 if missing
Partners
-2 if missing
-2 if missing
Purpose
-10 if missing
-5 if missing
Introduction
Not applicable
-20 if missing
Hypothesis
-10 if missing
-10 if missing
Procedure
-25 if missing
-10 if missing
Data
-20 if missing
-20 if missing
Analysis of Data (including any
questions and sample
calculations)
-20 if missing
-20 if missing
Conclusion
-10 if missing; -5 if one
sentence.
-10 if missing; -5 if one
sentence.
1. Do your best.
2. Turn it on ON TIME!
3. If you don’t know the answer to something, do some research:
a. Ask me.
b. Google it.
c. Discuss it with a friend in the class (that doesn’t mean copy)
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DO NOT CUT AND PASTE sections from my procedure and use that
as your write up. The handout is what I did to help you write
YOUR OWN Lab Report. The handout NEVER needs to be turned
in. Writeups must be done in the Lab Notebook for full credit. No
spiral notebooks are allowed for Lab Reports.
Lab reports aren’t meant to be “term papers.” You MUST use the format listed below! This is an
“example”of a GOOD WRITEUP for the Diaper Lab. You can write other things but you NEED the
headings and the stuff that is BOLDED is the stuff that should be written into your report, in your
own words. The non-bolded stuff is just snarky comments meant to illustrate.
The following can be written up before you get to lab.
Title:
Diaper Dandy Lab
Don’t just write…Diaper Dandy Lab…for the title. It may seem obvious that it’s the title, but
scientists are weird like that. Write Title: first and then give it some kind of catchy title.
Most of my students are way more creative than I am! Just do it! You’ll get points.
Date: the 12th of Never (this is ALWAYS the day you do the lab, not the day you write it up)
Partners: Bugs Bunny, Daffy Duck and Elmer Fudd (the purpose of partners is to double-check
if your data looks really weird)
Purpose:
The purpose of this lab is to see how much water a disposable diaper can really
hold.
Introduction:
The diaper has a chemical in it which absorbs water. It is a polymer called
sodium polyacrylate….
I give you lots of valuable information in the lab to help you with this section. It should be
about a page (I know, O and D), and don’t quibble on what defines a page. If you don’t
think it’s exactly a page, write more, until you do. You can also do research online (Google
something …it’s amazing what you can find) and report things here that you feel are
relevant and maybe even interesting. [My regular chem classes can IGNORE this section.
You don’t have to do it, but if you do, I’ll give you extra credit. My advanced classes need
to do it, or you will lose points in your report.] Remember, this has to be at least a
complete page, for full credit.
Hypothesis:
Try to write BEFORE you do the lab. When you already know what’s going to
happen, it takes all the fun out of it. A sentence here is perfectly acceptable also.
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Procedure:
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this is how I did the lab.
Step 1: I did this.
Step 2: I did that.
Step 3: I did something else.
Depending on the complexity of the lab, this could be a long section. Your procedure
doesn’t have to be the complete procedure that I gave you copied over into your notebook,
BUT it should contain enough detail so that I can look at it and recreate your experiment,
using NOTHING but your lab notebook. If you cut out my procedure and tape it or staple it
into your book, you will get 0 points for this section. A narrative is OK, but I find a bullet
list, or a numbered list of steps works best for this.
Note: sometimes we make procedure modifications on the fly for
reasons which (you know, STUFF happens)…be sure to add those
into your Lab Report, especially if you write the “given” procedure
up ahead of time.
Data:
(hint: read from left to right and then down, just like normal.)
Mass of X
Trial 1
This is where your data goes.
Volume of Y
It should be neat and organized.
Tables are good. Everyone should
record their own data.
Density of Z
Mistakes happen, and they happen
really easy that way. Also, if that
one person’s book somehow gets
wet or destroyed, and you lose
your data, then no one in the group
has any data.
Trial 2
This is the stuff that you collect
WHILE you are doing the lab.
It is OK for one person to weigh
something and come back and tell
everyone what the mass is. Please
don’t record all of the data in one
book, and then copy everything over
at the end.
EVERYONE should be recording data
throughout the lab. Ideally you will
do this directly into your lab
notebook.
The data is taken during lab and written into your notebook. Observations
also go in the data section. This part must be done DURING the lab time.
Let’s say you haven’t written anything up yet, but you’re doing the lab. If you write the data in your
book, it will be out of order. Is this OK? YES!! Simply title your page, “Lab Data for XYZ
experiment.” Record your data. When you write up your lab report, and get to the spot in the
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report where the data needs to be, simply write: Please see pg 17 for my original data. You don’t
have to re-write anything. Isn’t that easy!?
The following MUST be done AFTER lab is over!
Analysis of Data:
Number crunching
Sample calculation
Calculation of Error
Graph of your data (if appropriate). Always use Excel for graphs. NO hand drawn
and sloppy graphs
Discussion of Errors
Conclusions:
probably at least a paragraph. Tell me what you learned from your
experiment. STATE whether or not you believe your hypothesis was supported or was not
supported. If you were to do the lab again, how would you improve it, do it differently, or
expand upon it?
If you don’t have a notebook, GET ONE. If you absolutely can’t get
one, come and speak to me privately and I’ll see what I can do to
help you.
Some major DO’s and DON’Ts for lab reports. ALL of these rules and
suggestions in this handout apply to all labs for the entire year in
Chemistry.
1. Don’t assume I don’t read them. I don’t read every word of every Lab
(I’m not going to lie). But I do read enough to know that you did a good
job on the assignment, AND I do grade different sections carefully for
each lab report.
2. I might not catch you every time, but I will catch you eventually. Once I
do I will make sure to grade every word of you lab report very
thoroughly.
3. Labs are worth 25% of your grade and it is ridiculously easy to get 100
on every lab report. All you have to do is write up the lab in the format
I asked.
4. Do write your lab in pen. Maximum grade for pencil = 90.
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5. If you make a mistake line through it and move on. Only use a single
line, and don’t scratch it out so you can’t tell what was there. Scientists
need to have integrity and that includes showing everyone your
mistakes as well as your successes.
6. If you mess up a whole page or a large section of a page, put a big X
through the parts you don’t want me to look at. If you do this, it’s a
good idea to put a short explanation, such as “Used the wrong formula
to do calculations,” etc.
7. NEVER ERASE ANYTHING from your lab notebook or tear out a page. I
will deduct points. If it is a lab notebook from an old class, you won’t
need all of the pages for my class. Do not rip them out, even if they are
from an old class or when you were in 6th grade.
8. Do not cut and paste MY HANDOUTS into your lab book instead of
writing it over yourself.
9. Do number your pages at the top. Start on the very first page with 1.
The back of that page will be 2, etc.
10.Do have a “Table of Contents” at the beginning of your notebook so I
can easily find your lab reports. This should start on page 1.
11. Start your Diaper Lab Report on page 3.
12.Do research to write a quality introduction.
13.Do think of your lab report as a major assignment and do your best
work.
14.DO NOT COPY FROM ANYONE ELSE. If I find out, you will get a 0 for
the lab.
15.DO write your name on the outside in ink. Sharpies are good for this.
END OF DIAPER LAB HANDOUT!!
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