What is That Stuff?

November 3, 2010

by: Elaine Kotler

I created a lab using the Instant Snow Polymer (Sodium Polyacrylate) from Educational Innovations that I use in my 8th grade Physical Science Class as well as Summer School Programs that I teach for grades 4-9.  This lesson incorporates concepts of Conservation of Mass, Properties of Matter, Metric Measurement and Conversion, and Observation Skills.  The lab, as I give it to the students, is listed below.

Each student receives an empty baggie to be used for comparison, a baggie containing 12 grams of Instant Snow Polymer, use of a balance and a graduated cylinder.

I have already explained the Law of Conservation of Mass, and Density (they need to remember that the density of water is 1 g/ml, or look it up) prior to introducing this lab activity.  However, they do not know the terms exothermic, endothermic, hydrophobic or hydrophilic.  My students are allowed to look them up, but unless they make careful observations as they are conducting the experiment, they won’t be able to answer the questions later.

The final question “What is That Stuff?” garners some interesting answers. Some recognize a use for it as snow for ski slopes; others have suggested material for ice packs.  One suggestion was to use the powder to help clean up and absorb spills.

It is wonderful to see the faces of the students as they are in awe of what is occurring in the baggie.  I allow the students to color the water, if they so desire.  One year I did the lab on Saint Patrick’s Day.  Guess what color most students chose?

Elaine Kotler
Saint Paul School, Kensington, CT
Summer Options for Kids, West Hartford, CT
Kids on Campus, Middlesex Community College, Middletown, CT

What is That Stuff?

1.           Record mass of the empty baggie as given by Miss K (A)

2.          Without opening the baggie, use a scale to measure the mass of the bag with the contents in grams (B). Record data.

3.          Calculate the mass of original contents by subtracting the mass of the empty baggie from the mass of the baggie with the original contents.  Record data (C).

4.          Feel the contents of the baggie through the baggie and think about how it feels temperature–wise.

5.          Using a graduated cylinder, measure 160 ml of water. Record volume of water (D).

6.          Calculate the mass of the water. DO NOT MEASURE!!  Record data (E)

7.          Open baggie and add water to the powder.

8.          Immediately zip the bag closed.

9.          Shake the bag to mix the powder and water and watch what happens.  DO NOT OPEN THE BAGGIE.

10.       Without opening the baggie, take the mass of the baggie and its contents (F).  Record data.

11.        Calculate the mass of new contents by subtracting the mass of the baggie from the mass of the baggie and the new contents.  Record data (G).

12.       Feel the contents of the baggie through the baggie and think about how it feels temperature–wise.  Make careful observations.

13.       Add your measured mass for the original contents (C) and the calculated mass of the water (E).  Record data (H).

14.       You may now open the bag and play with the material.  It is non-toxic, however DO NOT PUT IN MOUTH.

15.        Clean up.

Student Sheet

You must look up any terms you are unfamiliar with that are used in this handout.

Measurements and Calculations 10 points

A = mass of baggie (g) ____

B = mass of baggie and original contents (g) ____

C= mass of original contents (g) B – A ____

D = volume of water (ml) ____

E = mass of water (g) ____

F = mass of baggie and new contents (g) ____

G = mass of new contents (g) F – A ____

H = C + E (g) ____

What is That Stuff?

Questions

1.       Explain why you needed to measure the mass of the baggie during the experiment. (15)

2.      Explain how you arrived at your answer for E, since the mass of the water was not measured. (15)

3.      Is your answer to G the same as your answer to H (± 3 g for margin of error)?  Explain why or why not. (15)

4.      Is this reaction exothermic or endothermic?  Explain. (15)

5.      Is the powder hydrophilic or hydrophobic?  Explain. (15)

6.      And, finally, what is that stuff?  Describe it, give it a name and describe one use for that stuff. (15)

NAME _________________  Score ________ out of 100

Teaching Observation Skills

March 9, 2010

by:  Matthew Campbell

One of the more important traits a scientist can have is the ability to observe.  Helping our students become better observers can be tricky.  Observation is a soft-skill and can be difficult to teach directly.  In my experience I also find that students tend to rush through labs to obtain the answer quickly.  This desire for speed is contrary to the pace required for careful, precise observation.

My solution for helping students become better observers is the science journal.  The purpose of the science journal is to encourage students to observe the science happening all around them.  The scope of the project allows for careful observations to be made which can then proceed into conclusions and validations of hypotheses. As an added bonus, the journal integrates literacy into the science classroom.  I encourage my students to select topics that appeal to them to increase investment in the project.   I do provide a listing of sample topics to help them better formulate their own journal topics.  Some of the topics covered in the journals have included:
    Reviewing newspaper/magazine articles for cases of good or bad science reporting
    Looking for science principles in sports (excellent for physics)
    Studying the changes in an ecosystem (e.g. plant growth, goose behaviour)
    Astronomical observations
    A recording of chemical additives found in the food that the student has eaten
    Beginning a new exercise regime
    Following weather patterns

The ideas for the journal are limited only by the student’s imagination.  I normally have the journal topics last for a unit or two, providing the student with a chance to study a different topic that may appeal to them.

A fantastic twist on the journal idea is to have the students blog their observations.  The integration of technology with journaling tends to improve student engagement. Additionally, the project gains credibility as it is now open in the public space and is no longer private between the student and teacher.  This interaction between the student and other Internet users helps the student desire to improve their writing, as they are now writing for an audience.  The student’s posting obtaining its first comment is normally a momentous occasion that only further entices the student to dig deeper on their topic.

There are numerous free blog hosting sites on the Internet, including EduBlogs, WordPress and Blogger.  Students can create their own blog or record their thoughts on a communal class blog.   Before starting a blogging journal, teachers should review the activity with administrative staff and ensure that parents are properly informed.  If there are concerns about personal information being revealed on the Internet, students can create an Avatar (I like DoppelMe) and use a pseudonym to write under.  If this approach is used, the teacher should keep a master copy of the pseudonyms for reference purposes.

Journaling, when combined with blogging, can be an excellent approach to improving not just observation skills but general science skills such as reporting, hypothesizing and drawing conclusions.  As an added bonus, the science of the classroom begins to filter into the students everyday experiences.