Convert liters, milliliters and microliters
Every step between these three units is a thousand. Learn to move between them without losing a factor of a thousand somewhere in the middle.
- A prefix carries a factor: Milli and micro are not just labels on a bottle. Each one names a specific multiplier, and a student who reads them as words rather than as numbers cannot convert.
- Which way the number moves: Going to a smaller unit always produces a bigger number. Students who memorize the factor but not the direction get the digits right and the size wrong.
Prerequisites are inferred: pending teacher review.
Re-learn the skill with worked practice and clear examples.
The factor is easy. The direction is what people get wrong, so build a check that catches it.
The table also lists 350 mL. A student writes 350000 L. Without redoing the arithmetic, how can you tell this is wrong?
Reviewed- A.The answer should carry a decimal point in every case
- B.Milliliters cannot be written in liters at all
- C.The unit got bigger while the number also got bigger
- D.The digits should have changed, not just the zeros
Show the worked solution ▾
Answer: C. The unit got bigger while the number also got bigger
- Step 1: Note which way the unit moved: From milliliters up to liters, which is toward the bigger unit.
- Step 2: Note which way the number moved: From 350 up to 350000, which is also bigger. Both cannot grow at once.
Why it's right: A bigger unit needs fewer of them to describe the same amount, so the number has to fall. Here both the unit and the number grew, and that is impossible whatever the factor turns out to be.
- A: Plenty of correct conversions come out as whole numbers, so the presence or absence of a decimal point proves nothing.
- B: Any volume can be written in any volume unit. Milliliters and liters describe the same kind of quantity at different scales.
- D: Multiplying or dividing by a thousand does move the decimal point and leave the digits alone. That part of the student's work is fine.
Aligned to Handling, Preparation, Storage and Disposal · reading level ~grade 9
The last row of the table is 4 L. How many microliters is that?
Reviewed- A.4000 microliters
- B.4000000 microliters
- C.400000 microliters
- D.40000 microliters
Show the worked solution ▾
Answer: B. 4000000 microliters
- Step 1: Take the first step: 4 L becomes 4000 mL.
- Step 2: Take the second step: 4000 mL becomes 4000 times a thousand microliters.
- Step 3: Check the zeros: Two steps means six zeros added to the 4.
Why it's right: Two steps down means multiplying by a thousand twice, which adds six zeros. Four liters is four million microliters, which is why nobody measures a stock bottle with a pipette.
- A: This took one step and stopped, so the answer is really 4 L expressed in milliliters wearing the wrong unit.
- C: This added five zeros, one short of the two full steps this conversion needs.
- D: This added four zeros, which is not a whole number of steps and cannot be right for any pair of these units.
Aligned to Handling, Preparation, Storage and Disposal · reading level ~grade 9
- A student who writes a conversion checks the direction before checking the digits, and catches the error that matters most.
Fill these in as you work through the lesson.
- Liter (the base unit, symbol L):
- Milliliter (a thousandth of a liter):
- Microliter (a thousandth of a milliliter):
- Sanity check (does the size of the answer make sense):
One liter is milliliters and one milliliter is microliters, so one liter is microliters. Moving to a smaller unit makes the number .
- State the two conversion steps without looking.
- Explain how you can tell you have gone the wrong way before you check the answer.
- Describe how the measuring tool on the bench can catch a conversion mistake.
A protocol says 30 microliters. Going up to milliliters is one step to a bigger unit, so the number gets smaller by a thousand: 0.03 mL. Going up again to liters is another thousand: 0.00003 L. Three zeros appear each time, and the direction never changes.