Enrichment · Passion Projects

Trust the reading,
then write it down.

Every measurement is only as good as the instrument behind it, and instruments drift. Check each one against something you know, an ice bath, a certified weight, a pH buffer, and log the readings. The log works out the error and the correction, fails anything outside your tolerance and tells you when each one is due again.

Add an instrumentWhat you get
$5one-time · every device you sign in on
Buy · $5

Included with the Caveat Academy pass and Whole-school licenses. Or get it in the Passion projects kit, $39 for 34 items.

Your instruments

The worked example is made up: a probe thermometer 0.8 °C high at boiling and eight days past its check, and a kitchen scale well inside ±2 g. Saved on this device only.

Loading the instrument form. If nothing appears, turn on JavaScript.

What you get

Enrichment · Passion Projects$5

What you finish with
A record per instrument with its ID, kind, unit, range, the tolerance you accept, the check interval and the last check; each check point with the reference, true value and reading; what you did and who checked. Works out error and correction at each point, flags points outside tolerance and checks overdue or due within 14 days, and lists every instrument’s next due date.
Who it is for
Students running science fair or lab projects, makerspaces, home bakers and brewers, and teachers keeping a classroom lab’s instruments in line.
Format
Browser log with a saved record per instrument. Prints one instrument’s record, a table of every instrument or a blank log to keep on the bench; downloads a spreadsheet (.csv); exports and imports a file.
Access
$5 one-time, yours on every device you sign in on; the tool opens once you are signed in with it. Included with the Caveat Academy pass and Whole-school licenses. Also in the Passion projects kit ($39) and the Enrichment Suite pass ($119), and 1 more bundle. Everything you type stays in this browser; nothing is sent to Caveat.
Where it lives
The Passion Projects space in Caveat Enrichment.
Support
Questions about access, an order or a correction: team@caveatacademic.com.

How to use it

  1. Give each instrument an ID and stick it on.
  2. Set the tolerance from the manual or from what your work needs.
  3. Check against two or more references across the range you use.
  4. Read the error; apply the correction, adjust or retire the instrument.
  5. Print the table and keep it with the instruments.

Add an instrument

The arithmetic

Error, tolerance and correctionError = reading − true valueCorrection = −errorPasses when |error| ≤ toleranceWORKED: BOILING WATER AT ABOUT 300 MTrue value99.0 °CReading99.8 °CError+0.8 °C, outside ±0.5Correctionsubtract 0.8 °C near 100Water boils about 1 °C lower for every 300 m orso of elevation, so look up your own altitude.
Correcting a reading is fine for a home or class lab; for anything safety-critical, adjust or replace the instrument.

References you can trust at home

A glass packed with crushed ice and topped with water, stirred, sits at 0 °C. Boiling water sits near 100 °C at sea level and lower at altitude. Certified masses check scales; fresh buffer solutions at pH 4, 7 and 10 check pH meters; gauge blocks check calipers.

Why two points

One check point shows whether a reading is right there. Two points, near the bottom and top of the range you use, show whether the error grows across the range, which a single correction would not fix.

Sources

  1. National Institute of Standards and Technology. Metrology for the classroom and Calibration services (nist.gov).
  2. U.S. Food and Drug Administration. Calibrating a food thermometer: ice-point and boiling-point methods (fda.gov; foodsafety.gov).
  3. Joint Committee for Guides in Metrology. International Vocabulary of Metrology (VIM), error and correction (bipm.org).
  4. U.S. Geological Survey. Boiling point of water and elevation (usgs.gov).

The worked example is made up. This log supports class, home and hobby work; regulated labs follow their own calibration procedures and accredited calibration. Nothing you type is sent to Caveat. Support: team@caveatacademic.com.