Eggs are a great tool for modeling cells in middle school.  Kids love to work with them and the challenge of keeping them safe is always fun.  Placing an egg in vinegar over several days will remove the shell.  Once complete, this bouncy egg is perfect for experiments.  Drop it in corn syrup and watch it deflate because of osmosis.  Put it in distilled water and it will swell up as water flows to areas of higher concentration.  Want to have some fun, let your students bring in test liquids when you are all finished, Mountain Dew, Kool Aid and Sprite are popular.  These sugary substances will color your eggs and make them swell up.  In addition, students can examine the eggs with a desk lamp to get a better idea of what is inside.  Don't forget to have the kids mass you eggs daily, this provides for good quantitative data that can be easily graphed.

Looking for resources for these activity's?  Check out a few of our cell resources.

Ever wonder how to share Google Drive projects with a class?  This brief video covers some of the basics of how I set up Google Drive for my students. 

Here's an example of a project I do that uses Google Drive.