g, mg, L, mL and µL
By the end of this lesson
- Convert common mass and volume units
- Keep units attached to every quantity
- Recognize thousandfold conversion errors
Examples use a decimal point; a comma groups thousands.
See it
Tissue-culture preparation depends on unit discipline. One gram equals 1,000 milligrams; one liter equals 1,000 milliliters; one milliliter equals 1,000 microliters. The numbers are simple, but a misplaced factor of 1,000 can make a preparation unusable.
Understand it
Convert common mass and volume units
Write the unit beside every value.
One gram is 1,000 milligrams, so 0.5 × 1,000 = 500 mg.
Keep units attached to every quantity
Convert units before multiplying if the units are not compatible.
One milliliter is 1,000 microliters; multiplying 0.056 by 1,000 gives 56 µL.
Recognize thousandfold conversion errors
Use leading zeros for values less than one and avoid ambiguous trailing zeros.
A leading zero and explicit unit reduce ambiguity when recording values below one.
Worked example
A calculation requests 0.056 mL. Since 1 mL = 1,000 µL, this is 56 µL, not 560 µL. For mass, 0.5 g = 500 mg. Write each conversion so the factor of 1,000 can be checked.
Explain your decision before opening the worked reasoning below.
Show the worked reasoning
The same number can represent different quantities; a missing unit must be clarified before calculation.
One liter is 1,000 milliliters, so 1.2 × 1,000 = 1,200 mL.
Never copy a numeric value without its unit.
Try it
Which notation makes a small volume clearest?
Use the worked example above to explain your answer in your own words before taking the quiz.
Lesson quiz
Assessment version: 2026-10-15-v2. Previous reading-completion markers are retained. This revised quiz has its own result.
Apply it
Use the worked example to write a short decision record: what did you observe, which rule did you apply, and what would you check before acting?
Completion marks reading progress, not a quiz pass or professional certification.