Who invented the steam engine... and when? Here's a brief history of steam power: 1st century CE:Hero of Alexandriademonstrates a steam-powered spinning sphere called an aeolipile. 16th century CE: Italian architectGiovanni Branca(1571–1640) uses a steam jet to rotate the blades of a smal...
What makes yo-yos go up and down? Why does a spinning yo-yo feel weird in your hand? How does a clutch yo-yo work? Who invented yo-yos? Find out moreWhat makes yo-yos go up and down?A yo-yo might look like a toy, but it's also an energy converting machine. Understanding how...