Popcorn Lab

 

Introduction/Purpose:

You will be performing three trials to determine the average water content of popcorn.  In your conclusion to this lab, be sure to discuss your accuracy, precision and sources of error, as well as the average %H2O of your three trials.  Remember, in order to discuss accuracy, you need to find out the true value for the %H2O of popcorn. 

 

Homework Assignment:  Prepare a data table to record your results.  To do this, you’ll need to read the lab carefully, and create a clear table that will hold all your data for the correct number of trials.  Suggestion: pretend to do the lab, and write down fake numbers.  Then create the table.

 

Materials:

400 mL beaker

Popcorn, cooking oil, aluminum foil

Bunsen burner, ring and ring stand, ceramic support, sparker

Hot Hands or beaker tongs (DO NOT USE CRUCIBLE TONGS!)

 

Procedure:

  1. Get the mass of your 400 mL beaker.
  2. Add enough popcorn to form a single layer in the bottom of the beaker.  Get the mass.
  3. Add just enough oil to barely cover the popcorn. 
  4. Place your square of aluminum foil atop beaker.  Poke big air holes in the cap, but not so big that popped corn can escape.  Mass this combination of popcorn, oil, beaker, and foil.
  5. Pop the popcorn.  Don't let any escape!  Don't scorch the popcorn!  Let cool by placing the beaker directly on the lab countertop.  Remove foil during cooling to allow steam to escape. 
  6. Do not place the beaker on the balance until it is cool enough to carry by the BASE.
  7. Determine the mass of the oil, foil, beaker and popped corn.
  8. Repeat these steps two more times.  DO NOT WASH THE BEAKER; just wipe as much residue out of the beaker as possible. 

 

Hints for Trouble Free Popping:

Start off with your bunsen burner as high as possible.  As soon as the first kernel pops, reduce the flame height (not color!) of the burner by about 1/2 to prevent over-heating and cracking of the beaker.  Do not attempt to pop every kernel: stop as soon as the popping slows appreciably.

 

Data:

You need a table to record three sets of data.  All data and calculations must be grams except %water.

 

%water = (water lost/popcorn)-100%

 

NOTE:

All data and calculations must reflect appropriate significant figures.  Use your best judgment when deciding which data sets to include in your average.  You must defend (in your conclusion) any decision to not include a data set.