Classroom setup

[mccartys_firstys]

So, here is my situation, I am a first-grade teacher in Utah. I went into our local pet store to find out about invertebrates for my students to study for science. I used worms this year and the kids did not really take to them. The owner said he would give me a tank kit and as many hermit crabs as I would take (the tank is 10 g.) Apparently, he has too many as anyone can tell by his tank setup. I figured if I took some they would definitely have a better quality of life than they do now. I left with the kit and told him I would be back later this week for the crabs. Here is what is in the kit- 10g Terrarium with sliding screen top, 5lb Vita-Sand, Hermit crab soil
Hermit crab mineral blocks, Combo Repti-Rock water, and food dishes, Hermit Crab care guide, Hermit crab water conditioner, Hermit crab salt water conditioner, Hermit crab food. I am planning on buying a 2nd habitat for my house during breaks and expanding their habitat throughout the year. Now I know these kits don't really have everything you need for a thriving and happy pet so this is where I will need your help. I would like to be able to have my students really learn from these amazing creatures (more than just they don't have a backbone.) I think it would be a good lesson on quality of life, needs vs. wants, adaptation, habitat (ecosystem), nocturnal, etc. The possibilities are endless. I also think it would be a good lesson on the difference between caring for our class goldfish, plants, and now Hermit Crabs. So here come the questions.
1. How many crabs can I rescue and still ensure they would thrive well in a 10 G. tank?
2. What else do I need to purchase to make sure their needs are met?
3. What lessons and ideas does anyone want to share.

This is going to happen so please be kind.
Thank you in advance
Mrs. McCarty
Proud teacher of Fantabulous Firsties

[StellaCrab]

I do not recommend keeping more than four small crabs, or two medium crabs in a ten gallon tank. Eventually, they will need an upgrade as they molt and grow bigger, but you can keep anywhere from two to four small crabs (size of a ping pong ball) in a ten gallon for a good while.

You'll need all the basics and essentials to keeping hermit crabs healthy. There is a helpful link for the crab care page on this website, and here is the link.
https://hermitcrabparadise.com/crabcare/