the other comment about click together vinyl flooring was possibly a good idea. I have used a metal oil drip pan on one of my machines to prevent damaging my bench. this should be good to cover most of your concerns. Here is a link to one similar. https://www.amazon.com/Hopkins-11430-Galvanized-Dishwasher-Refrigerator/dp/B000F5XQMO/
Here's an inexpensive project that you're children can help you with and makes a great thank you that will be enjoyed by children for years to come:
Get a couple of these oil drip pans and some chalkboard paint. That's actually the whole project, paint them and hang them up. Boards are magnetic or of course can be used with chalk.
Be sure to talk to principal/director (a good idea anyway as there may be something specific but inexpensive they are looking for, it is very unlikely they will say, "No thanks, our school has everything we need.") as various local regulations can dictate what is allowed in the classroom including "homemade" items.
Also the board can be mounted outside and great with a bucket of sidewalk chalk, if you are mounting on a chain link fence you can decorate the back as well as it will be seen from the other side.
Hope this helps :)
edit:fixed link
Maybe something like this?:
https://www.amazon.com/Hopkins-11430-Galvanized-Dishwasher-Refrigerator/dp/B000F5XQMO