I second this. A lot of my STEM posts are just simple experiments for kids. Then I do a deep dive on who invented the mechanism im exploring and such. You could do somrthing like "who can make the strongest invisible ink." Then reward everyone who enters on a sliding scale: Rewarding the winner the most.
Something like this would be SUPER easy to enter. People could just use lemon juice. But there are more complex invisible inks that are more difficult to make and MUCH stronger. So someone could really go crazy and win first place.
not that taping pasta and marshmellows together is difficult, but i think people are just too lazy to go to the store honestly. They want to enter that day or they forget.
Also you should try the 3 other letters in STEM before you give up. I sort of suck at Engineering lol. That's just me.