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.
By Sam. The crossbow was invented in Ancient China during the Zhou dynasty, around the year 700 BC. A Chinese text, from about 200 BC, gives credit to a Mr. Ch'in of Ch'u for inventing the crossbow. It consisted of a horizontally mounted bow, with a stock and trigger mechanism added.