All substances have properties. These describe how a subject looks and behaves. Substances have both physical and chemical properties. Developing the periodic table The periodic table was developed by ...

Every field of science has its favorite anniversary. For physics, it’s Newton’s Principia of 1687, the book that introduced the laws of motion and gravity. Biology celebrates Darwin’s On the Origin of ...

This year we celebrate the 150 th anniversary of Mendeleev’s achievement in formulating the structure of the periodic table that we use today. He announced his structure in 1869, but the challenge of ...