# Thermometer questions **URL:** \ **Category:** Factual Questions\ **Created:** [March 21, 2020, 3:01pm UTC](https://boards.straightdope.com/t/thermometer-questions/849956 "2020-03-21T15:01:14Z")\ **Posts on this page:** 5\ **Page:** 1
**Author:** ![What\_Exit](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/what_exit/32/10652_2.png) [@What\_Exit](https://boards.straightdope.com/u/What_Exit)\ **Post date:** [March 21, 2020, 3:01pm UTC](https://boards.straightdope.com/t/thermometer-questions/849956/1 "2020-03-21T15:01:14Z")
We have a digital Braun (in the ear) that is around 22 years old now. Fresh 9 volt battery in it. My readings have been around 95.1°f and my wife using a different cover read 95.3°f Neither of us feel warm to the hand touch, I was just making sure the Braun worked. **Is it reasonable to assume that adding about 3° to the reading is the actual Temp?** I had 3 old Mercury (liquid in glass) oral thermometers but all of these appear to be dead. I thought the old fashion Mercury in glass types were not suppose to go bad. I carefully cleaned them and they appear to not react anymore. **Do the glass oral thermometers go bad? They are from the late 90s or 2000, could they not be Mercury?** I am very confused, but don’t remember trying to use these glass oral thermometers ever. ---
**Author:** ![ftg](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ftg/32/2801_2.png) [@ftg](https://boards.straightdope.com/u/ftg)\ **Post date:** [March 21, 2020, 3:14pm UTC](https://boards.straightdope.com/t/thermometer-questions/849956/2 "2020-03-21T15:14:18Z")
It’s highly unlikely that one glass thermometer, let alone 3 from the 90s or later, would go bad just sitting around. Did you shake them down to below the scale or whatever mark the thermometer has as the “start” point? Is the scale from ~94-100 so that they are intended for this purpose? As I noted in another thread, the latest studies show that about 97.5 F is “average” body temperature. But there is a wide spread. Since YMMV, it’s a good idea to test your temp with the ear thermometer at different times of the day to get an idea that it is indeed measuring over a range, etc. ---
**Author:** ![What\_Exit](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/what_exit/32/10652_2.png) [@What\_Exit](https://boards.straightdope.com/u/What_Exit)\ **Post date:** [March 21, 2020, 3:23pm UTC](https://boards.straightdope.com/t/thermometer-questions/849956/3 "2020-03-21T15:23:57Z")
I just did a very vigorous shake down on one and it dropped to the start point. Take my temp now for 3 minutes. And that got me a read of 98°. \*\*Thank you very much. \*\* I feel kind of stupid. ---
**Author:** ![Squink](https://avatars.discourse-cdn.com/v4/letter/s/b5e925/32.png) [@Squink](https://boards.straightdope.com/u/Squink)\ **Post date:** [March 21, 2020, 6:36pm UTC](https://boards.straightdope.com/t/thermometer-questions/849956/4 "2020-03-21T18:36:35Z")
Be careful with your Mercury thermometers. They are now valuable antiques. I have a 40 year old one (Walgreens) that works great. These new thermocouple/digital ones always seem to die after a year or two. ---
**Author:** ![yabob](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/yabob/32/2821_2.png) [@yabob](https://boards.straightdope.com/u/yabob)\ **Post date:** [March 21, 2020, 10:34pm UTC](https://boards.straightdope.com/t/thermometer-questions/849956/5 "2020-03-21T22:34:41Z")
If you prefer the mercury ones, you can now buy new similar ones filled with [galinstan](https://en.wikipedia.org/wiki/Galinstan) instead of mercury.