Week 6 Group C Lab Data: Cremation/Pottery Firing


For this week’s lab, my group (Group C) was working with Group D to build the cremation pyre in the center of the island. Additionally, we fired our 6 pots in order to test how well they would survive based on the tempers that were used to create them, in a callback to the week 3 pottery lab. After building the fire (for information on how we did that, I highly recommend Caroline’s lab data writeup which displays some very helpful drawings) and heating up our pots to around 200 degrees Celsius in Group A/B’s metal fire pit, we put them on the pyre with the intent of heating them up to 800 degrees Celsius. After starting the fire, we took notes on the temperature of the pots as time progressed. Below are some of these observations, in addition to data taken on the weight of the lamb meat with and without the brooch and covering.

Our Data:

Weight of lamb meat (plain)Weight of lamb meat (w/ cloth and brooch)Weight of lamb meat/bones (post-cremation)
Weight of cremation substitute (before and after cremation). Here are some of the numbers for the weight of the lamb meat that we placed on the pyre. The weight and cloth added up to 63 grams. Unfortunately, the class did not have time to weigh the post-cremation product, but when that happens this page will be updated with how much weight was lost and, by consequence, how successful the cremation part of our experiment was.

Time of dayPot temperature (°C)Notes
2:38pm130The pot was in Group A/B’s pit at this time. Albert’s pot was occasionally being rotated, though with no consistency.
2:58pm192Fire taken out of pit and placed on the pyre (soon to be lit)
3:05pm63Rapid cooling occurred while we were setting up the teepee around the pyre
3:12pm33Coolest point in temperature the pots reached, even though this was after the fire was lit at sometime around 3:06-3:10pm
3:31pmHi (used the wrong temperature recorder)If I had to guess, the temperature here would be somewhere in the 600 degree range, though unfortunately the temperature recording error on my part means that this is unknown
3:37pm750Peak temperature of the pots that I recorded. Note the gap in time between 3:37p and 3:55p, during which time the fire very easily could have grown to above 800 degrees, as was our goal
4:21pm621The fire is mostly dead at this time, though the pot still retains a lot of heat
Temperature of Albert’s pot during firing. The above table records the temperature of Albert’s pot during the firing process. Albert’s pot was the only one of our large groups’ pots on the side of the pyre closest to Boliou (alongside mine and Margaret’s) that was visible while the fire was going, so his pot is what I was able to gather data on. An important note to highlight is that the pots cooled very quickly between the time they were taken off of Group A/B’s fire and by the time we were able to start the cremation fire. It is interesting to consider how the overall result of a lot of spalling would have changed if the fire had already been started when we transferred the pots over and they were able to maintain a stable temperature without cooling off.

OriginalAfter 1 dayLossAfter firingTotal Loss
Diameter (rim)5.5cm5.5cm0cm5.5cm0cm
Diameter (widest)8.5cm8.5cm0cm7.8cm0.7cm
Wall section1.19cm1.19cm0cm1.033cm0.157cm
Albert’s pot dimensions before and after firing. Here is some of the data showing the final dimensions of Albert’s pot and its change over time. As you can see, it lost quite a lot of weight (120g), diameter at the widest point (0.7cm), and wall section length (0.157cm) during firing. Albert was in the group that used the least amount of chaff in his pot temper, and it seemed like this factor led to spalling (my pot also had quite a bit of spalling and was in the same temper group as Albert’s).

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