ETA High-Range, Dual-Scale, Mercury-Free, Safety Thermometers for Indoor Science Use (Pack of 10)

They dont work.

good

tl;dr: two thermometers may read as much as 14 degrees off; about half of them are very difficult to read because the actual thermometer and the scale are misaligned; one of them warped significantly in 90°C water.This is probably a good case of "you get what you pay for" as these thermometers were purchased because they were cheap and would arrive before classes go home for winter break. I have significant issues, but if you, like me, just need thermemeters immediately, they are technically thermometers that you can get on short notice on a budget.1. Readings: I bought these specifically for an insulated container experiment, where my students used household materials to insulate a jar. Water was poured from a kettle into the containers, left for three minutes, and the initial readings varied widely (from 96°C to 77°C). Accepting that this was in different vessels, I repeated the test using only two vessels, with five thermometers (and an actual glass scientific thermometer) in each one. Both glass thermometers registered over 90°C (91°C and 92°C) after three minutes. The purchased thermometers varied from 94°C to 80°C.2. We were measuring cooling rates, and the thermometers seem to measure change more precisely than actual temperature. I.e, a change of 10°C on one thermometer from this set is also registered as a change of 10°C on another thermometer from this set.3. One thermometer is significantly warped to the point that the plastic around the bulb is bent and I'm worried the thermometer will crack. I only gave the thermometers a cursory inspection upon arrival, but none of them were warped significantly. The plastic is bent, in terms of straightness, but also in terms of the shelf that the bulb sits on.4. These thermometers have a ribbon of spirits that indicates the temperature, but four of my thermometers have the glass tube oriented in such a way that to see the ribbon effectively (with any kind of width showing), I have to turn the thermometer so that it is difficult to read the scale. I will probably try to fix this by twisting the glass tubes, but given the construction, I think they are likely to break.

These thermometers aren't great and they aren't bad, just an average product that can get the job done. I used these for a class experiment and it was tough to get the liquid inside to return to room temperature after testing a warm temperature. Students had to shake the thermometers for a long time, and some still didn't return to room temp. The bulb inside also twists around, making it hard to read the thermometer. It isn't very easy to twist the bulb back to the front, but it can be done.

These are perfect for science projects - being able to complete multiple tests at once helps a lot. We did start off with all in one bowl to see that they all worked and said the same thing. Would buy again if I ever needed to…but I think we’re set.