(If this belongs in a different section feel free to move it mods! :))
I'm helping the girl I babysit to do her science fair project, and we've decided on doing a water ecosystem in a bottle/jar. There are going to be two identical bottles (plant wise) with different 'stocking'.
The plan is to have a tablespoon of soil, then 2 inches of sand substrate (probably either playsand or leftover flourite black) and fill it with an equal number of anacharis and ludwigia stems, and then a measured amount of duckweed/water lettuce. I'm either going to do this in a very large soda bottle or a locking large jar.
The 'experiment' would be to have 3 shrimp in each bottle, but one bottle will have Cherries, and another Ghost. (cheapest and most available to me). The experiment will measure which species thrives more.
Any problems/tips/advice? I'm trying to keep it as simple as possible (I was thinking about testing the water and using those results but I figured it would be a bit to advanced for 4th grade
) and as safe as possible for the shrimp.