site, thus students can clearly see how far the liquid should come up
the tip for the indicated volume. A key on the top of each pipette tip
box indicates the tip housed in each well (Figure 2). The key helps
students quickly find the appropriate tip, and makes it more likely
for students to return the tip to the slot that it came from. This helps
maintain tip order when multiple students are using one box.
When the trainee pipettes accurately, liquid will rise to the
mark on the side of the tip, but not past it. Training Tips allow stu-
dents to see immediately if they are drawing the correct amount of
liquid into the pipette. If students push past the first stop while
depressing the pipette plunger, or do not allow the liquid to slowly
enter the tip, the liquid will not be drawn equal to the marked line
and/or bubbles will form. The marked lines draw students’ atten-
tion to the pipette tip, and it is more likely they will notice bubbles
and adjust their technique. In addition, if students use the incorrect
pipette—for instance, P200 to pipette 5 μl—the liquid will not
reach the mark. Training Tips do not require a balance for students
to determine if they have pipetted accurately; however, a balance is
still needed for pipette calibration and may be useful when assess-
ing student progress. The marking strategy is applicable to any
brand of pipette tip and takes roughly one to two hours per set
to make. An entire set is not needed for every student in a class,
In our lab, we have found that allowing students to practice
with Training Tips helps them learn good pipetting technique
and focuses their attention on the amount of liquid being drawn
into the pipette. We have found that depending upon the color
of the tip and the volume of liquid being pipetted, pipetting col-
ored liquid can provide an even more dramatic visual benchmark
to see if they are pipetting correctly. Importantly, Training Tips
quickly show students if they are not pipetting correctly and has
thus made students seek assistance much sooner. The implementa-
tion of this training method has made students focus more intently
on learning to pipette. In turn, although training time has not
increased, student proficiency has improved.
Most students are unfamiliar with μl volumes before working
with micropipettes. Training Tips provide visual benchmarks for
the difference between volumes that, even to the trained eye,
appear very similar (Figure 1A and B). Such small differences in
volume can have dramatic effects on experimental success and
reproducibility. For volumes of liquid that can be accurately pipetted with multiple tip types, it enables students to see how high the
liquid should rise in each tip. For instance, pipetting 5 μl will look
and feel different if you use a P10 as opposed to a P20 (Figure 3A).
Figure 1. (A) P200/20 Training Tip, 200 μl–2 μl tips.
(B) Examples of Training Tip labels and how 50 μl differences in
volume register on P1000 tips.
Figure 2. Example of key provided on the top of the training
Figure 3. Examples of how volume can appear different on
different tips. (A) 5 μl on P10 and P20 tips. (B) 200 μl on P200
and P1000 tips.