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  • Fiona McNeill

Canadian spring is making our science difficult!

The Toxic Allure lab is a Perspex® box built on a mezzanine floor in a larger laboratory. It looks incredibly cool. It is, in fact, incredibly hot.


It was originally built as a biohazard lab. The box was built for safety. It isolates biological work from the rest of the building. Isolation means ventilation is through a HEPA filtered system and the room is sealed. The room becomes very hot. Worse, we run a water circulator at 37ºC in the room. We make it hotter and humid. This makes it challenging for us because we are covered in layers of PPE. We take lots of breaks outside. We drink lots of water. It is also a difficult challenge for our experiments.


As we measure makeup on pigskin, the skin slowly dries out. We wondered how this affects the colour. To the eye, the edges can become a little red. Our question was whether the centre of the sample, where we measure, changes too. This week, we decided to test how the colour of pigskin might change over time.

For our experiment, we took pigskin samples out of the freezer and started measuring them immediately with the spectrometer. We measured the colour every few minutes. Using a thermocouple, we tracked the temperature over time. Our first few measurements tracked the colour as the pigskin thawed. Later measurements measured the skin as it warmed up.


We learned that frozen pigskin is more yellow. Megan, our co-op student, pointed out this might make sense because a symptom of frostbite is that skin looks yellow. As the skin thawed, it first became much less yellow, and then, over time, it started getting more yellow again, but much more slowly.

This was interesting but creates a difficulty. How do you look at how lead makeup changes perceived skin colour if the skin colour is constantly changing? I wanted to know if there was a time period over which the colour was fairly stable. I wanted to know if the colour change always followed the same pattern.


We repeated the experiment three times. Experiments 1 and 2 were both done on day 1. They gave identical results. As we left for the day we though ‘Yay! We have a system with predictable results.’ Of course, when we came in on day 2, we got different data.


Now, part of our problem is that it is spring in Canada. The temperature goes up and down a lot. This is ideal for tapping maple trees. It makes controlling indoor temperatures hard. On day 1, the previous overnight low had been -2 ºC. The heating had been on early morning and the lab was very warm when we came into work. The daytime high then rose to 17 ºC and, well, we suffered. The temperature in the lab was 27 ºC. The overnight low that night was 12 ºC. The heating did not run. Although the next day the outside temperature went up again to 18 ºC, the lab was not as hot.


On day 3, the pig defrosted and warmed more slowly. The colour changes were less. This tells me I need to keep the spectroscopy pigskin at a lower temperature in the fume hood, while still running our Franz cells at 37 ºC.


Such is the life of a research scientist. Some days you get to ponder the big questions. Other days are spent thinking about how on earth you can keep a piece of pigskin cool.

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