Rate of Water Uptake Calculator
💧 Diffusion, osmosis & transport. Use the Rate of water uptake (potometer) formula to find rate, tube radius, distance the bubble moved, time: pick the value you want, type the others, and the answer updates as you go.
The bubble moves d mm along a capillary tube of radius r.
Pick the ○ next to the value you want to find, fill in the others, and it solves as you type.
What each letter means
| Quantity | Unit |
|---|---|
| Rate | mm³/min |
| Tube radius | mm |
| Distance the bubble moved | mm |
| Time | min |
Worked example
Find the rate when Tube radius = 0.5 mm, Distance the bubble moved = 40 mm, Time = 2 min.
Using rate = (π r² × d)/t: Rate = 15.708 mm³/min.
Frequently asked questions
What is the formula for Rate of water uptake (potometer)?
rate = (π r² × d)/t. The bubble moves d mm along a capillary tube of radius r.
What do the letters stand for, and what units are used?
Rate in mm³/min, Tube radius in mm, Distance the bubble moved in mm, Time in min.
How do you calculate rate?
Put the values into rate = (π r² × d)/t. For example, with Tube radius = 0.5 mm, Distance the bubble moved = 40 mm, Time = 2 min, rate = 15.708 mm³/min.
Can I solve for a different value?
Yes. In the calculator above, pick the circle next to any value (rate, tube radius, distance the bubble moved, time) and fill in the others: it rearranges the formula for you.
