ELI5: Explain Like I'm 5

Alkahest

Alkahest is kind of like a magical potion that people used to believe could dissolve any substance into a liquid. It was a really popular idea in the olden days when people thought that everything was made up of just four basic elements - earth, air, fire, and water. They believed that if they could find a liquid that could dissolve all these elements, then they could transform anything into its purest form.

Think of it like this - let's say you have a toy car made of plastic, metal, and rubber. You could use a hammer to break the car into pieces, but you'd still have separate pieces of plastic, metal, and rubber. But if you had Alkahest, you could just pour it over the broken pieces and watch as it dissolves everything into one liquid. Then, once the liquid evaporated, you'd be left with something pure that's made of only plastic, metal, or rubber.

Of course, alkahest is just a myth. There is no such thing as a magical liquid that can dissolve everything. But people were really curious and hopeful back then, and they believed that alkahest was the key to unlocking all the secrets of the universe. Today, we know that the elements are more complex than just earth, air, fire, and water, and we use things like chemistry and physics to understand how things work.