Illustrated Guide to Home Chemistry Experiments

90 DIY Science: Illustrated Guide to Home Chemistry Experiments

FIGURE 5-24: A section of glass tubing that has been drawn

Trying to force glass tubing into a cork or stopper is one of
the most frequent causes of injury in home labs. If you apply
pressure even slightly off-axis, the glass tubing may snap and
impale you. Fortunately, it’s easy to avoid such accidents.
Proceed as follows:

1. First, make absolutely certain that the glass tubing is of
   the proper size to fit the hole in the stopper. If you try to
   force 5 mm tubing into a stopper drilled for 4 mm tubing,
   for example, things are sure to end badly.

FIGURE 5-25: Lubricate the glass tubing with glycerol or oil and

then rotate it as you slide it into the stopper

IERTInS nG GLASS TUBInG InTO
CORKS AnD STOPPERS SAFELY
2.ubricate the tubing with glycerol, mineral oil, or a L
similar substance. (Many chemists use water, but I
recommend something slipperier.)

3. Using heavy gloves or a towel to protect your fingers,
   align the tubing with the hole in the stopper, and slide it
   into the hole, rotating the tubing constantly as you do
   so. Apply only as much pressure as needed to cause the
   tubing to slide into the stopper, and apply that pressure
   as close as possible to the face of the stopper, as shown
   in Figure 5-25.

CLEANING GLASSwARE

• lways do at least a preliminary cleaning as soon as possible A
  after you finish using the glassware. Contamination that
  rinses away easily when fresh may harden overnight into a
  deposit that’s difficult or impossible to remove.


• Before you clean glassware, always examine it for cracks,
  starring, chipping, or other damage. Dispose of damaged
  glassware by rinsing it to remove as much contamination
  as possible, wrapping it in several layers of newspaper, and
  discarding it with the household trash.


• For small-bore items such as glass tubing, pipettes, and
  so on, force or draw clean tap water through the glassware

Dirty glassware is one sure sign of a sloppy chemist. Use the following guidelines to keep your

glassware in like-new condition.

several times to rinse out most of the contamination. Then

draw clean sudsy water through the glassware several times,

followed by

drawing several rinses of tap water through the glassware,

and finally by drawing distilled or deionized water through the

glassware several times. Use a rubber bulb or zero-residue

canned “air” (not your mouth) to blow out any remaining rinse

water and set the glassware aside to dry. No further cleaning

is needed.

• For glassware with accessible inside surfaces—such as
  beakers, flasks, and test tubes—as soon as you finish using
  the glassware, let it cool (if applicable), dispose of the