Around 1590, Zacharias Jansenn of Holland invented the microscope. Jansenn, an eyeglass maker by trade, experimented with lenses and discovered that things appeared closer with combinations of lenses. Over the past 400 years, several refinements to microscopes have occurred, making it possible to magnify objects between 200 and 1,500 times their actual size. It was not until 1931 that Max Knott and Ernst Ruska invented the electron microscope, which allowed them to magnify objects up to 300,000 times their normal size. Today, the latest microscope technology can capture students interests and imaginations with light, handheld imaging devices that can be connected to a classroom computer.