Glurch Meets Oobleck

 

Some materials do not conform neatly to the designations for solids, liquids, and gases. For example, a colloid is a material that consist of one substance suspended within another. The suspended material is comprised of particles so small that they don't sink to the bottom of the second substance. Together, the two materials display properties unlike those of their separate components. Some examples: smoke (a solid suspended in a gas), fog, meringue, protoplasm, homogenized milk, synthetic rubber, and mayonnaise.

 

This lab is designed to study: ‑

viscidity (stickiness) –

resiliency (elasticity) –

fluidity (ability to flow)

 

You will soon realize that you must develop your own operational definitions for these properties (just how can you obtain quantitative data?)

 

After you make each colloid devise your own testing criteria and answer the questions found at the bottom of the page. Turn in the answers and your samples for your grade.

 

GLURCH:

1) obtain approximately 4 tablespoons of liquid laundry starch, 2 tablespoons of white glue, and a small pinch of salt

2) pour the starch into the cup, add salt, and stir until it is completely dissolved

3) add the white glue and stir about 30 times with the spatula

4) squeeze out the excess starch until the substance becomes doughy

5) remove from the cup and knead

6) if runny add a few more grains of salt

 

OOBLECK:

1) obtain approximately 4 tablespoons of cornstarch and 2 tablespoons of water

2) pour the water into the cup and add cornstarch a little bit at a time while stirring

3) when the mixture becomes too thick to stir, remove from the cup and knead

4) add a few drops of water if the oobleck is too crumbly

 

Questions:

1) If both colloids were poured, which would fill a container faster?

2) Which colloid would be better measured in mg than in mL?

3) Which colloid would make a better substitute for thumbtacks?

4) Which substance would make less noise when pulled up from a surface?

5) Which colloid would be more difficult to hide in your closed fist?

6) Which colloid would make a better emergency soccer ball?