activity 1

Above is the original graph, taken from the Journal of Plant Physiology 1926. The rotation of the image was imperfectly done using paint hence the red box to at least have straight axes to base on.

These are the x-y variable values and their corresponding pixel coordinate values:

x	y		x(pixels)	y(pixels)
0	0		120	75
2	25		225	140
4	40		330	179
6	80		435	283
8	120		540	387
10			645

-from these it is calculated that the x-axis has 52.5 pixels per unit while the y-axis has 2.6 pixels per unit.

Below are tables for the pixel coordinates, values in pixels (coordinates minus origin coordinates), and the actual values (values in pixels divided by the calculated pixels per unit for each axis) of each X mark on the original graph.

coordinates	:		values (in pixels):
x	y		x	y
121	140		1	65
136	135		16	60
264	134		144	59
308	138		188	63
336	209		216	134
370	283		250	208
440	365		320	290
457	368		337	293

actual values:
CO2 evolved	staining time
0.019048	25
0.304762	23.07692
2.742857	22.69231
3.580952	24.23077
4.114286	51.53846
4.761905	80
6.095238	111.5385
6.419048	112.6923

From the values of the last table, the following graph was (re)constructed:

-i give myself a grade of 10 because even though the format of the y-axis values is different from the original graph; the overall appearance and upon closer inspection, the marked data points, are about precisely reconstructed.