What a nice thing!
Just a thought: when you go to speak to the class, if you make and take a betta care fact sheet, some of those may spread throughout the community and end up in homes, etc...which may even trickle down as changes at a local pet shop as customers ask for larger tanks, heaters, healthier fish, etc... You could include a link to this site, too!
When bettas are happy, they are lots of fun rather than dull boring fish just wasting away in the bottom of a cold bowl. When people enjoy their betta more, they talk about it and word spreads around...
Great way to throw a rock into the pond to make some really effective waves! APPLAUSE!