I remember being stuck at one point as a kid. Eventually I gave in and ordered the official hint book. Mind you, that meant physically mailing a paper and I guess the money to the company and then waiting several weeks for the reply.

I finished the game two days before the book arrived (use physics book with horse). But it was still worth it. The book also contained a novelization of the story written by Bernard. Title: My Physics Adventure or It’s Never Too Late To Stop Polution So Let’s Start Yesterday