Week 3 Lab Data Group A: Pottery

Jacob Forster Rothbart \\ Lab Group A

Updated 05/09/2025; previously updated 04/24/2025

Composition — The composition of our clay is shown in the following table. Mass represent amounts of materials used per person. We tried to measure the amount of water that added in the tempering process by measuring the total mass of the tempered clay. This was unsuccessful, due to more mass being lost during the tempering and wedging process than gained through adding water.

Material	Mass (grams)	Percent by Mass (%)
Store-bought Clay	500	83.3
Sand	80	13.3
Fine Gravel	19	3.2
Chaff (Wood Shavings)	1	0.2
TOTAL	600	100

Change Over Time — Measurements were conducted when the pots were first made and after various intervals. Those measurements are shown in the following tables. Note that all loss values are compared to the original measurement. In some cases it was not possible to measure lengths at precisely the same place both times. This is denoted in the table with an asterisk.

After One Day — Measurements taken after 21 hours.

After Six Days — Measurements taken after 6 days.

Before Firing — Measurements taken after 21 days.

After Firing — Measurements taken 1 day after firing.

TEST BAR

Note: the test bar did not survive firing

Measurement	Original	After 1 Day	1 Day Amount Loss	1 Day Percent Loss	After 6 Days	6 Day Amount Loss	6 Day Percent Loss	Before Firing	Before Firing Amount Loss	Before Firing Percent Loss	After Firing	After Firing Amount Loss	After Firing Percent Loss
Mass (grams)	100	85	15	15%	84	16	16%	84	16	16%	x	x	x
Height (cm)	0.5	0.4	0.1*	20%*	0.4	0.1*	20%*	0.4	0.1*	20%*	x	x	x
Length (cm)	17.5	16.9	0.6*	3.4%*	16.7	0.8*	4.6%*	16.6	0.9*	5.1%*	x	x	x
Width (cm)	4.5	4.3	0.2*	4.4%*	4.1	0.4*	8.9%*	4.2	0.3*	6.7%*	x	x	x
Scale Bar Length (cm)	10.0	9.6	0.4	4.0%	9.5	0.5	5.0%	9.4	0.6	6.0%*	x	x	x

ELIE

Measurement	Original	After 1 Day	Amount Loss	Percent Loss	After 6 Days	6 Day Amount Loss	6 Day Percent Loss	Before Firing	Before Firing Amount Loss	Before Firing Percent Loss	After Firing	After Firing Amount Loss	After Firing Percent Loss
Mass (grams)	442	404	38	8.6%	374	68	15%	374	68	15%	347	95	21%
Height (cm)	9.5	9.2	0.3*	3.2%*	9.6	+0.1*	+1.1%*	9.7	+0.2*	+2.1%*	9.7	+0.2*	+2.1%*
Rim Diameter (cm)	10.5	9.5	1.0*	9.5%*	9.5	1.0*	9.5%*	9.7	0.8*	7.8%*	9.7	0.8*	7.6%*
Diameter at Widest Point (cm)	10.5	9.5	1.0*	9.5%*	9.5	1.0*	9.5%*	9.7	0.8*	7.8%*	9.7	0.8*	7.6%*
Wall Section Thickness (mm)	7.07	6.23	0.84*	12%*	6.45	0.62*	8.8%*	6.50	0.57*	8.1%*	7.8	+0.73*	+10.3%*

JACOB

Note: pot fell and cracked when fire collapsed, only the main piece was recovered. Only measurements that were not impacted by this loss are recorded here.

Measurement	Original	After 1 Day	1 Day Amount Loss	1 Day Percent Loss	After 6 Days	6 Day Amount Loss	6 Day Percent Loss	Before Firing	Before Firing Amount Loss	Before Firing Percent Loss	After Firing	After Firing Amount Loss	After Firing Percent Loss
Mass (grams)	554	511	43	7.8%	463	91	16%	461	83	15%	x	x	x
Height (cm)	9.5	9.4	0.1*	1.1%*	9.2	0.3*	3.2%*	9.2	0.3*	3.2%*	9.2	0.3*	3.2%*
Rim Diameter (cm)	10.0	9.5	0.5*	5.0%*	9.4	0.6*	6.0%*	9.0	1.0*	10%*	x	x	x
Diameter at Widest Point excluding rim (cm)	9.0	8.8	0.2*	2.2%*	8.8	0.2*	2.2%*	8.7	0.3*	3.3%*	x	x	x
Wall Section Thickness (mm)	8.4	7.1	1.3*	15%*	6.1	2.3*	27%*	7.15	1.25*	15%*	6.39	2.01*	24%*

SASHA

Measurement	Original	After 1 Day	1 Day Amount Loss	1 Day Percent Loss	After 6 Days	6 Day Amount Loss	6 Day Percent Loss	Before Firing	Before Firing Amount Loss	Before Firing Percent Loss	After Firing	After Firing Amount Loss	After Firing Percent Loss
Mass (grams)	346	322	24	6.9%	300	46	13%	299	47	14%	280	66	19%
Height (cm)	8.0	7.88	0.12*	1.5%*	7.83	0.17*	2.1%*	7.79	0.21*	2.6%*	7.84	0.16*	2.0%*
Rim Diameter (cm)	6.5	6.45	0.05*	0.77%*	6.43	0.07*	1.1%*	6.37	0.13*	3.0%*	6.38	0.12*	1.8%*
Diameter at Widest Point (cm)	8.5	8.02	0.48*	5.6%*	7.86	0.64*	7.5%*	7.86	0.64*	7.5%*	7.82	0.68*	8.0%*
Wall Section Thickness (mm)	6.0	4.5	1.5*	25%*	4.0	2.0*	33%*	4.01	1.99*	33%*	4.53	1.47*	25%*

UGO

Measurement	Original	After 1 Day	1 Day Amount Loss	1 Day Percent Loss	After 6 Days	6 Day Amount Loss	6 Day Percent Loss	Before Firing	Before Firing Amount Loss	Before Firing Percent Loss	After Firing	After Firing Amount Loss	After Firing Percent Loss
Mass (grams)	382	355	27	7.1%	324	58	15%	322	60	16%	301	81	21%
Height (cm)	7.0	7.0	0.0*	0%*	7.0	0.0*	0%*	7.0	0.0*	0%*	7.0	0.0*	0%*
Rim Diameter (cm)	6.0	6.0	0.0*	0%*	6.0	0.0*	0%*	6.0	0.0*	0%*	6.0	0.0*	0%*
Diameter at Widest Point (cm)	9.5	9.0	0.5*	5.3%*	8.5	1.0*	11%*	8.5	1.0*	11%*	8.5	1.0*	11%*
Wall Section Thickness (mm)	10	10	0*	0%*	10	0*	0%*	10	0*	0%*	10	0*	0%*

* = measure of loss that is potentially inaccurate (see above)