I show them my ideas for an interplanetary gun.

That is my big mistake. I am no gun expert, and it shows. They just take it as an opportunity to lecture me on how little I know, and point out every possible flaw. But they don't get it! This is no joke! The Martian invasion could arrive at any moment!

Should I appeal to national pride - to make the biggest gun ever? Or should I try to use psychology? Or do something else?