2.16 describe experiments to investigate diffusion and osmosis using living and non-living systems.

Diffusion:

Experiment:

Cut 3 blocks of gel into different sized cubes

Pour coloured water over each cube

Start stopwatch

Remove cube, cut in half

Measure distance travelled by the dye into each cube

Record results

With this experiment we can also show how surface area affects the rate of diffusion, after working out the surface area to volume ration of each cube we can see that a smaller object has a larger surface area to volume ratio, which means that there is a faster rate of diffusion 

HOW TO FIND SA/V RATIO:

Surface area: length x width x number of sides

Volume: length x width x height

= SA: V

simplify

Smaller objects have a higher surface area to volume ratio

Osmosis:

Experiment:

Different concentrations of glucose (same volume) in a beaker

Cut potato strips to the same length and size

Weigh them

Leave the potato in the beaker for 30 mins

Weigh and measure again after experiment

Repeat experiment

Osmosis:

If the solution of sugar is stronger than the solution in the potato cell, water will leave the cell

If the solution of sugar is weaker than the solution in the potato cell, the water will enter the cell

The potato will gain weight when the solution of sugar is weaker than the other solution and lose weight for the opposite. The weight of the potato would stay the same if the concentration of both the substance and the potato cell are the same.