As an avid Chelonian pet parent I do not recommend a 10G.
Most turtles and tortoises are runners or swimmers. That is, they want room. Consider the zoomed floating dock, and an underwater cave. These eat real estate.
A MrAqua30G or a 50 breeder tank (better) would be better for the animal and fetch a higher resale value. Rimless tanks have thicker glass and kids like to be hands on.
Keep it shallow until they develop their lungs or they can drown.
Eheim canister filters are a better deal than the turtle filters. Pondmaster 150 is ideal but not pretty to look at. You need a muck filter. Turtle poop is nasty. Potted plants (no soil) filled with small riverstones will hold up to a baby turtle and help clean the water.
Use small river rocks to barely cover the bottom. $5 for 40lb at lowz.
It's fall so you may find a young Painted turtle or Snapper at the lake. I prefer you get a captive raised baby and only a northern species as you then won't need a heater. Turtles and glass heaters don't mix. Please don't buy a Slider, they are Southern species.
Snappers are more fun and retain their natural instinct to hunt food.
Just get one turtle, they are loners, 2 males will eventually maim each other.
Reptomin turtle stick food, earthworms, and live minnows are best. Insects, too. Many here will gladly donate duckweed. Painted turtles love to eat floating plants.
For lights- Desert fluorescents give plenty of UVB. Depending on the classroom, a small spotlight may be needed for a few hours of basking.
Need more info?
Mr3, Mr12, Mr50's, Killer Vivarium, Whiskey Pond