Despite advent among the oldest pieces of modern measurement equipment, liquid in glass thermometers are more delicate than their history suggests. These long tubes of glass, most familiar from feverish childhood days, are hollow in the center to allow for the expansion and contraction of liquid that is highly sensitive to thermal fluctuations and ranges commonly encountered in working conditions. Mercury and alcohol are the most common liquids found in this kind of thermometer, although other organics can be used for more particular applications.

Shattering, obviously, is the most common fear with these instruments but there is a more insidious enemy abreast: pressure.

When liquid in glass thermometers are shipped by air, the un-pressurized cabin of the airplane can engage with the liquid inside the glass and cause the previously-contiguous strand of liquid to break and separate via “bubbles”. These bubbles, often referred to as a “separated column,” are just places along the capillary (lumen of the glass tube) where the liquid was compressed and spread enough for air trapped within the tube to separate the fluid and create space. These bubbles render the thermometer unreliable and inaccurate as their calibration relies on a contiguous strain of fluid. Therefore, we discourage sending your liquid in glass thermometers via air travel to transport them to our facility. Most airlines also forbid sending mercury or lead products on planes, so it’s safest to rely on ground. Fortunately we can fix most thermometers with this problem but it takes time and resources so there is an additional fee to repair the instrument when it arrives as such.


Best Shipping Practices:


1: Bubble wrap is your friend

Bubble Open  Bubble Closed

We encourage you to fully encase your thermometer in blister wrap, several layers deep, to prevent the hustle-and-bustle of shipment to turn your trusty laboratory instrument into a pile of glass shards (and potentially bleed mercury!).


2: Sturdy packaging is a must


Box Open Box Closed

Cardboard is requisite here–despite the padding of a bubble envelope, it can get bent (thus breaking your instrument). Boxes don’t get bent.


3: Ground shipping is better for your instrument and your wallet

Complete Box

Ground shipping keeps your costs down and precludes the possibility of air travel placing expensive bubbles into the instrument.


However you decide to ship your thermometers, we do hope that the end address is our lab where they will receive the same top-notch calibration service appreciated by clients across the globe. We look forward to receiving your instruments and, as always, if you have any questions don’t hesitate to reach out!