Johann Bessler was a man who lived a long time ago (in the 1700s). He made a machine that he claimed could run forever without needing any extra energy. This machine was called the "perpetual motion machine."
Now, you might think that a machine running forever without needing any extra energy is impossible. And you're right! The law of physics says that energy can't be created out of nothing, so a machine like that can't exist. But Johann Bessler believed that he had found a way to create a "perpetual motion machine."
He tried to show people that his machine really worked. He invited lots of important people to watch it run, and they saw that it really seemed to be running without any extra energy. But some people thought that maybe he had hidden a power source somewhere, or that it was all just a trick.
Eventually, people started to doubt Johann Bessler, and he became known as a fraud – someone who pretended to do something impossible. He died without ever revealing the secret of his "perpetual motion machine."
So even though Johann Bessler was a very clever inventor, he couldn't break the laws of physics. And that's why there will never be a machine that can run forever without needing any extra energy.