Water Potential Calculator
Ψ from solute and pressure potential for AP Biology.
Enter your values
sucrose = 1, NaCl = 2
Results update instantly as you type — no submit needed.
Results
- Water potential Ψ
- -3.715 bars
- Solute potential Ψs
- -3.715 bars
- Pressure potential Ψp
- 0 bars
- Water moves
- Into this solution (it is more negative)
Quick answer
Water potential Ψ is the sum of solute potential and pressure potential; water always moves from higher Ψ to lower Ψ.
Ψ = Ψs + Ψp, Ψs = −iCRT
At a glance
| What it does | Ψ from solute and pressure potential for AP Biology. |
|---|---|
| Category | Science |
| Inputs needed | Ionisation constant i, Molar concentration, Temperature, Pressure potential Ψp |
| Main output | Water potential Ψ |
| Formula | Ψ = Ψs + Ψp, Ψs = −iCRT |
| Cost | Free — no sign-up, no download |
How to use the Water Potential Calculator
- 1Enter the ionisation constant for your solute.
- 2Enter molarity and temperature in °C.
- 3Add pressure potential if the cell is turgid.
Inputs explained
- Ionisation constant i
- sucrose = 1, NaCl = 2
- Molar concentration(M)
- Enter the molar concentration you are working with.
- Temperature(°C)
- Enter the temperature you are working with.
- Pressure potential Ψp(bars)
- Enter the pressure potential ψp you are working with.
Worked example
Using the values the calculator loads with:
Inputs
- Ionisation constant i1
- Molar concentration0.15 M
- Temperature25 °C
- Pressure potential Ψp0 bars
Results
- Water potential Ψ-3.715 bars
- Solute potential Ψs-3.715 bars
- Pressure potential Ψp0 bars
- Water movesInto this solution (it is more negative)
Frequently asked questions
What is R in the water potential formula?
The pressure constant 0.0831 litre·bar per mole·kelvin used in AP Biology.
Why is solute potential negative?
Dissolved particles lower the free energy of water, so adding solute always reduces water potential.
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.