In this lab, students will have the opportunity to see the complexity of the different phases of matter. This lab will allow students to investigate polymers and physical properties, while connecting these concepts to the phases of matter. Students will also better understand that some substances are not easily identified as a particular phase of matter and that some substances can have characteristics of more than one phase of matter.
Always wear safety goggles when handling chemicals in the lab.
Students should wash their hands thoroughly before leaving the lab.
When students complete the lab, instruct them how to clean up their materials and dispose of any chemicals.
Food in the lab should be considered a chemical not for consumption.
Teacher Notes
The following chemistry vocabulary would be helpful for the teacher to review prior to the lab:
I suggest that the teacher prepare the zip lock bags with 1/3 cup glue prior to the lab to save time. This will allow students to begin the lab with their zip lock bag of glue already prepared.
All materials except the food coloring should be made available for the students. Stations may be a good way to organize the materials for the students.
I suggest that at step 4, the teacher should go to each student and add the food coloring. This will prevent any staining of clothing.
This lab can be completed individually, or in pairs.
The teacher may want to engage the class in a discussion about polymers, states of matter, phase changes and non-Newtonian Fluid prior to the lab activity.
Creating the polymer inside of zip lock bags keeps this process much cleaner, and makes for an easy clean-up process!
Below are photos of procedure step 6 (on left), as well as the final substance created (on right).
Molecule: the smallest particle of a substance that retains all the properties of the substance. A molecule is composed of one or more atoms.
Non-Newtonian Fluid: a fluid that has the characteristics of both a solid and a liquid, depending on the amount of force applied to it.
Polymer: a long chained molecule consisting of smaller repeating molecular units (known as monomers).
For the Student
Pre-lab Questions
What is a physical property? Give three examples of physical properties:
What are the three states of matter?
Can a substance exist as multiple states of matter at the same time? Explain.
Materials
Borax Powder
Water
Elmer’ s Glue
Plastic cup or small beaker
Zip Lock Bag
Stirring rod or popsicle stick
Graduated cylinder
1 tsp measuring spoon
Food Coloring
Safety
Always wear safety goggles when handling chemicals in the lab.
Wash your hands thoroughly before leaving the lab.
Follow the teacher’s instructions for cleanup of materials and disposal of chemicals.
Food in the lab should be considered a chemical not for consumption.
Procedure
Collect your sealed bag of pre-measured glue. There is 75ml of glue in your bag.
In your data table, record 3 physical properties about the glue in your baggie.
Using your graduated cylinder, measure 50 mL of water into the baggie. Seal the bag and gently mix the contents.
Choose a food coloring to add to your mixture.
Mix your coloring into the mixture. Double check that your baggie is completely sealed before mixing the contents.
Collect a small plastic cup. Using the graduated cylinder measure 25ml of water into the cup. Using a measuring spoon, add 2 tsp. of Borax into the cup.
Using the Popsicle stick at your table, stir the mixture until the powder is mostly dissolved (some will not dissolve completely).
Open your baggie. Carefully pour the mixture from the cup into the baggie. Reseal the baggie, but attempt to remove as much excess air as possible. Make sure that your baggie is completely sealed.
Gently massage the mixture. You will need to continue doing this for a few minutes in order for the mixture to become firm and uniform. You should continue kneading the baggie until there is no runny substance remaining in your baggie.
In your data table, record 3 physical properties about the final substance in your baggie. You can open the baggie and touch the final substance with your fingers.
Observations
Three Physical Properties of glue (step 2)
Three Physical Properties of final substance (step 10)
Analysis
The title of this lab is called, “Changing a Monomer to a Polymer.” After completing this lab, what do you think that these two words mean?
Look up the words “polymer” and “monomer,” what do they mean? Compare this to your thoughts in question 1.
How are physical properties and states of matter related? What about physical changes and phase changes?
Conclusion
Now that you have created your very own polymer, think of an everyday item that is made of polymers. Explain what the item is, and why you think it might be made from polymers.
