Try showing the adults something along the lines of the
Symphony of Science.
Or, you could point out famous scientists on television like the Mythbusters, Bill Nye, or Neil deGrasse Tyson. If you're really desperate, you could also point out the (former) popularity of shows like Battlebots and Robot Wars (too bad they aren't aired anymore).
Another great thing to mention would be the $9 million in scholarships FIRST has available. Money talks.