B5b Osmosis visking

What is visking tube

Can be used to model a cell membrane

Apparatus and materials

• Visking tubing 30cm long in a beaker of water

• 20cm3 of water (0 % sucrose solution) in a small, labelled beaker

• 100cm3 of 5 % sucrose solution in a small. labelled beaker

• 20cm% of 20 % sucrose solution in a small, labelled beaker

• Marker pen/labels

• Balance

• 3 x boiling tubes labelled 1, 2, and 3

• Paper towels

Method

• Add sucrose solution to a section of Visking tubing – a selectively permeable substance used to model a cell membrane.

• Weigh the Visking tubing and its contents.

• Add the Visking tubing to a beaker of water.

• Leave for 1 hour.

• Pat the Visking tubing dry to remove excess water.

• Reweigh the Visking tubing and its contents.

• The Visking tubing will gain mass as water will have moved from an area of high concentration (outside) to an area of lower concentration (inside).

  
  

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