How Can I Show 16 Year Old Son That Investing Now Is Huge For His Future?

I have a 16 year old son who has been accumulating birthday money and stuff over the years, and has started working very part time (4-5 hours a week at $15/hour for a company my mom owns).

He is of the mindset that he needs to just keep his money in his piggy bank in his room so he can get it when he needs it. I’ve tried explaining to him that compounding interest is the 8th wonder of the world, and that if he starts a high yield savings account at 16, he will have a 5-6 year head start, which come the tail end of his investing life would make a significant impact on his total assets. This doesn’t even account for if he decided to invest in the market, which could have even greater benefits.

Unfortunately, at 16, he doesn’t want to think about what happens when he’s 70.

What are some good ways to illustrate or explain to him that even if he’s not investing a large sum right now, he’s so young that those extra 5-6 years worth of saving/investing will be significant down the road?