Key relationship
h=2σcosθ/(ρgr).
Physics · Practical apparatus
Capillary rise with detergent
Read the meniscus height above the reservoir. A smaller bore produces greater rise. The detergent selector demonstrates reduced tension using an explicit calibration factor.
Open the interactive experiment →Capillary rise with detergent
மெல்லிய குழாயில் ஏற்றம் ஆரத்திற்கு எதிர்விகிதம். சவர்க்காரம் பரப்பு இழுவிசையை குறைப்பதால் உயரம் குறையும்.
Key notes, relationships and model limits
Practical tip
Read the meniscus height above the reservoir. A smaller bore produces greater rise. The detergent selector demonstrates reduced tension using an explicit calibration factor.
Common trap
Capillary rise also depends on contact angle. Detergent changes the surface-tension setting in this model.
Model limits
static capillary rise, wetting liquid; detergent factor is a chosen model calibration, not a claimed measured commercial concentration.
What you will learn
Adjust capillary rise with detergent apparatus, observe its reading and derive the indicated physical quantity.
Try the experiment
Try both scenarios, change one control, and predict the result before checking the graph and readouts.
Think of it this way
Change one input while keeping the others fixed, as you would in a controlled experiment.
Worked example
For σ=72 mN/m, ρ=1000 kg/m³ and r=0.5 mm with θ=0°, h≈29.36 mm.
Why this matters
The model connects capillary rise with detergent with an observable reading. Check the equation and assumptions before applying it.
Before you start
SI units · algebra · graph reading
Check your understanding
Doubling bore radius with unchanged liquid gives capillary height?
- Twice as large.
- Half as large.
- Unchanged because surface tension is fixed.
Read the explanation
Half as large.
Course connection: Virtual apparatus preparation. Check exact board/exam membership in the syllabus sources. Physical practical work remains necessary.