Chardakov's Banana Experiment

Authors Avatar

Becky Saveker

Chardakov’s Banana Experiment

Introduction

  The ability of water molecules to move is known as their water potential. Water molecules always move down a concentration gradient towards a region of lower water potential, that is, to where there are fewer water molecules, to where the water potential is relatively more negative.

  As the water potential of one solution decreases, the density of the solution increases and as the water potential of a solution increases the density of this solution decreases. This would mean that if at all mixed, the less dense solution (i.e. the one with the lease negative water potential) would float on top of the denser solution (the one with the most negative water potential).

  The movement of water molecules down a concentration gradient (from a higher water potential to a lower water potential) through a partially permeable membrane is called Osmosis.

Apparatus

  • 12 test tubes
  • 1 test tube rack
  • 1 banana
  • 1 knife
  • 2 syringes
  • 1 square tipped needle
  • 1M sucrose solution
  • Methylene Blue (stain)
  • Water
Join now!

Method

  Put the 12 test tubes into 6 pairs and label one pair 1M, one pair 0.8M, one pair 0.6M, one pair 0.4M, one pair 0.2M, and finally one pair 0M. Each pair then needs to have 10cm³ of the relevant solution put into it. For example, the 1M pair of test tubes need 1M sucrose solution put into them, the 0.8M pair need 0.8M solution put into them, and so on. However, because there is only 1M sucrose solution available, the other ...

This is a preview of the whole essay