AQA AS Biology

Revision Notes

3.2.4 Three-way Taps

Apparatus & Techniques: Three-way Taps

  • Three-way taps can be used in conjunction with potometers and respirometers
  • They allow for repeat readings to be taken easily, eliminating the need for the apparatus to be reassembled each time
  • Potometers:
    • When used with a water reservoir they allow for the air bubble to be returned to the start of the tube by allowing water to enter the system
  • Respirometers:
    • The three-way tap can be used with a syringe to push the bead of coloured liquid back to the start

Three-way tap, downloadable AS & A Level Biology revision notes

The image above shows a respirometer set up with a three-way tap. The three-way tap allows for the drop of coloured liquid to be returned to the start of the ruler after each repeat of the experiment.

Author: Lára

Lára graduated from Oxford University in Biological Sciences and has now been a science tutor working in the UK for several years. Lára has a particular interest in the area of infectious disease and epidemiology, and enjoys creating original educational materials that develop confidence and facilitate learning.

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