Making explosive gas is a basic skill, and doing it can teach you a lot about chemistry. What you use that gas for is up to you. But please be careful.
Want to make everyone think you have super strength? Or maybe you want to do a short film where it looks like the fabric of reality is breaking down? All you need is some aluminum, some gallium, and some patience.
Or, to be more precise, practical spoon-melting. Do you know about a de-lite-ful little trick that some scientists like to play on one another that causes a spoon to melt in hot liquids? Did you know that once it caused the victims to fill themselves with mercury?
You gotta love it when science goes goth. Gallium, a silvery metal, can be made to pulse like a living heart when touched with an iron nail. Take a look at a robot's heartbeat, and find out how this metal heart works!