wiki/ news/ 2004-02-12 - Measurement of foam density

Ivan, Glenn, Marilyn (lab analyst)

Measurement of dielectric foam density

Tim and Andrew discussed the data from Monday's tests. According to Tim's calculations, there's approximately 5% more polyethylene in the BRD CPAs than in the basement CPAs per square area (this takes the thickness into account). Why this is we can't explain.

We're now very, very, VERY curious about what the density measurements are... one thing that could epxlain it would be a change in density of the foam over the roll.

Preliminary Test plan

  1. Cut exactly 6 inches of foam tape from each sample.
  2. Measure the weight of each foam sample.
  3. Using a volumetric flask, measure the ammount of volume each sample takes up.


Using sizzors and a caliper we actually cut exactly 150 mm of tape from each sample roll. This was difficult because the tape would stick to one side the sizzors. We chose the side away from the sample for where this sticking would occur, and cleaned off the residue after each cut with alchohol. I used a square and a straight edge of my workbench to mark the tape for where to cut in order to get a perpendicular 90 degree cut. I labeled the sample from the beginning of the roll dated 14-Sep-2003 with a #1, and the sample from near the end of the roll with a #2.

With help from Marilyn, we went into the lab and measured the weight of each sample. We placed an empty weight boat into the analytical scale to find the tare weight, then peeled the backing off of the tape, dropped it into the boat, and then recorded the weight. We did this for each sample.

Marilyn said the finest resolution of volume measurement they had was +/- 1 mL which would not return a meaningful volume, so we did not make that measurement.


Weight of sample #1 0.5217 g
Weight of sample #2 0.5889 g
Scale accuracy +/- 0.1 mg
Scale information Sartorius model A200S; s/n 38110191; Room 142
Weight of typical weight boat 6.8645 g

We kept the foam samples in their respective weight boats should we want to do further work with these.

  • Cutting the tape to 150 mm

  • Measuring the weight of the tape