Here's a website that discusses using sand and gravel in hydroponics.
http://www.frogchorusfarm.com/growingmediagravelsand.html
However, I'm sure it will be easier for you to find these answers in your science book.
the advantage of gravel is :
the disadvantage of gravel:
the advantage of sand
the disadvantage of sand
3 answers
our teacher took our books
weight is a strong disadvantage to both
sand disadvantage is it stays wet
advantage of gravel: air gets to root hairs.
For my orchids, I have found expanded clay particles are superb. I add 1/2 expanded clay, 1/2 shredded rubber tires.
sand disadvantage is it stays wet
advantage of gravel: air gets to root hairs.
For my orchids, I have found expanded clay particles are superb. I add 1/2 expanded clay, 1/2 shredded rubber tires.