Because it can get soaked an loose up.
I suggest the use of cardboard to make cardboard egg crates.
If you're thinking of doing so, I'd use cardboard for a good example.
A good item for a cell membrane would be a thin plastic or cardboard
The key is making sure the cardboard house experiment is well insulated. Do this by painting the inside of the house flat black, and making sure the windows you cut into the cardboard are clear and facing the sun.
A pasteboard form for making boxes etc.
Instructions on making cardboard chairs can be found from many different sources. Some websites with these instructions include Youtube and PackNBoxNow.
Making models involves creating representations of complex objects or process.
the ingredient is cardboard
classifying
Tomorrow, we'll be making models of dragonflies in class.
http://www.hiveworkshop.com/forums/f282/create-models-only-free-tools-107544/ That's a good tutorial for model making.