I usually mark the coming of spring with the first woodcock, the first morning cardinals and robins, the first woodland flowers, orange-throated darters and the first chorus frog chorus.
Back in my early teaching years we would venture to a nearby pond that only held water in the early spring to collect frog eggs. I haven’t looked for eggs for awhile and I was a bit late, this year. This Sunday I did some wet wading and found some eggs in a pond that is dry most of the year.
Maybe it is too late for this year but for next year you could get a permit from KDWP and collect a group of eggs to raise in class.
Here’s a great web site from Greg and Lynnette Sievert from ESU with recordings and tons of photos of developing Kansas frogs and toads–a great resource.