Which diaper absorbs the most liquid?

Like many first time moms, after having my son, I kept trying different diapers to see which one worked the best.  At the same time, I was searching for a fun way to introduce the scientific method with my students.  Suddenly, I read something that sparked this lesson idea:  “Keep experiments simple for students.  Answer a real life question you have.”

Too often, we teachers, try to bring science experiments into the classroom (with not help from schools or our curriculum) that are frankly just too difficult.  Whether we don’t have the materials necessary or even the knowledge of why this chemical reacted a certain way, etc.  These obstacles have always made bringing true experimentation into the classroom pretty much non-existent.  I hate this.   So, then my diaper problem seemed like something my kids could handle.

I was honest with my students and told them that we were going to create an experiment so that it could benefit me and my son.  The students were totally into it!  I’m sure working with diapers had a little something to do with it as well.  *Tip:  You might want to give the rules on inappropriate toilet humor before you begin.*

The first thing I did was show the kids a video (found on youtube.com) about the scientific method.  It’s pretty cheesy, but it did it’s job of getting the kids excited and in a great mood.  I then passed out the scientific-method.docx (as seen below):  steps of the scientific method to be glued in their notebooks, a lab write-up sheet for the experiment, and diaper data.  The last one is a sheet listing the three diapers to be tested with some basic information which was taken straight from each brand’s website.

After students looked over all the data and discussed at their table groups any prior knowledge they might have, each group had to agree on a “team” hypothesis.

**Please note:  I purposely threw a wrench in this experiment so as to teach the importance of variables later on.  One of the diapers to be tested was Huggies Overnights.  Last year, one student questioned the validity of the experiment, but this year…NOT A ONE.  I do this to see if they notice that all the diapers are not the same and that they should be.  The overnights even state they are specifically made for 12 hours of absorption.*

After each team has a hypothesis, THEY design their experiment and record all the necessary steps on the form.  I simply tell them the materials they will have at their disposal and they plan the rest.  Of course, I walk the room and monitor their discussion, but I do feel the best results occur if they are left alone on this first attempt.  They learn SO much from their mistakes.  For example, only 4 out of my 6 teams felt it was necessary to EQUALLY MEASURE the amount of water to be added to each diaper.

The next day the students conduct their experiments and record their observations in their notebooks.  It’s pretty awesome how into it they all are.  The experiment probably took about 30 minutes to complete and results were then discussed as a class.

 

Every group, except one, found Huggies Overnights to hold the most water (of course!).  We then began evaluating each team’s process and determining whether our results were valid.  Finally, I exposed my secret about the overnight diaper.  I immediately showed them a Bill Nye video on the importance variables and precise measurements in a science experiment.

We also ended up cutting the diapers open to reveal how in the world the diapers held so much water.  This is another reason why I love this experiment.  It fosters so many more questions the students have that lead to more investigation.  Inside the diapers is a crazy gel like substance that starts off looking like cotton, but when it comes into contact with liquid has a chemical reaction which changes the entire look and feel of their material.

I finish up this lesson with a student journal reflection about what we would do differently if I let them do this again.  Also, a homework assignment to research and find out what the material is inside of a diaper.

Hope your kids enjoy!