Are all sponges Biodegreadable? (science project)?

Question

For science class, I need to make a container out of the bottom half of a half gallon paperboard mik carton that will protect an egg from the impact of being launched. I cannot use food or food by products and the product(s) must be biodegradable.

I was going to use a sponge for one of the products, but a friend told me that not all sponges are biodegradable.

I was just wondering whether all sponges are biodegradable, if not, which ones are, and where I can buy them. (hopefully a grocery store!)

p.s. other ideas for the project are expeted

Answer 1

Natural sea sponges are biodegradable, as they are living organisms from the ocean.

Look for a natural sponge in places like Bed, Bath and Beyond, or Bath and Body Works.  Generally, you are not going to find them in a grocery store (unless it's a high-end store).

Answer 2

Natural sponges (which were animals, when they were alive) are fully biodegradable. They cost a whole lot more and do not have the same homogeneous character as NYLON "sponges" which ought to say that they are nylon on the package.

Answer 3

I dont kno 4 sure but i do know that sponges were once actual sponges living in the sea so i imagine that as definately possible.