I originally used this instructable as a demonstration to explain osmosis to my classes.
Over the years many of my pupils told me they'd tried it for themselves at home (got their interests, half my job was done). I've started using this method as a practical with some of my classes with great results and plenty of opportunities for pupils to visualise cells and osmosis also for extension work to challenge the more able (you know the one that has finished, while you're still explaining what to do to others).
Over all it does take 5 days but you can take about 2 days off by putting the eggs in vinegar yourself but it does loose some of its WOW.
I took these photos before I decided to make this instructable so sorry if photo doesn't quite fit the step.
Step 1: Equipment
2 x eggs
about 500ml of vinegar (I normally use the distilled white vinegar, but this bottle was only 14p)
2 x 250ml Beakers
bag of sugar
2 x 500ml beakers
Post it notes or Sticky labels
1 x balance (the more accurate the better)