The
Colorimeter actually uses polystyrene cuvettes to desigh. Fifteen of these
cuvettes and lids are supplied with the Colorimeter. The cuvettes have a volume
of approximately 4 mL. Two opposite sides of the cuvette are ribbed and are not
intended to transmit the light from the LED. The two smooth surfaces are
intended to transmit light. It is important to position the cuvette correctly
in the Colorimeter, with a smooth side facing the arrow at the back of the
slot, and with the ribbed edges facing left and right. The light travels from
the LED at the top, through the cuvette, to the detector below the slot. Just
like most spectrophotometer sample tubes, individual plastic cuvettes vary
slightly in the amount of light they absorb.You may choose to ignore these
differences. For most lab exercises, this variation will not have a noticeable
effect on experimental results. For best results, variation in light absorbed
by individual cuvettes can be controlled either by using the same cuvette for
all trials of a particular experiment or by matching a set of cuvettes.
