Chemical bonding happens when two or more atoms join together to form a molecule. It is a general principle in science that all systems will try to reach their lowest energy level, and chemical bonding will only take place when a molecule can form that has less energy than its uncombined atoms.hemical bonding happens when two or more atoms join together to form a molecule. It is a general principle in science that all systems will try to reach their lowest energy level, and chemical bonding will only take place when a molecule can form that has less energy than its uncombined atoms.
Human beings were able to create tools around 2.5 million years ago-but we first made bows and arrows 64,000 years ago. The invention of the weapons was a huge leap for our ancestors, enabling them to hunt far more effectively.
Ever since they were invented, catapults have been a deadly war weapon. The catapult was invented by Dionysius of Syracuse around 400 B.C. In Greek, the word catapult means to throw into. When he designed the catapult, Dionysius wanted to create an effective war weapon. The first catapult designed worked like a crossbow. To be able to make the catapult more powerful, it was made larger and stronger and set on a tripod.