The burner with an air hole
The BUNSEN BURNER is named after the German chemist Robert Bunsen, who worked out the design with his technician, Peter Desaga, in Heidelberg in 1855. A collar at the bottom opens and closes a small air hole. With the hole shut, the gas burns with a wobbly yellow flame that is easy to see, so it is used as the safety flame when the burner is not in use. With the hole open, air mixes in and it burns with a hot, roaring blue flame, almost invisible in daylight.
Bunsen put his burner to remarkable use. With the physicist Gustav Kirchhoff, he heated substances in its clean flame and studied the coloured light they gave off through a prism, and in 1860 and 1861 they discovered two new elements, caesium and rubidium, from the bright lines in their light.
A cloth merchant who saw bacteria
In the 1670s a cloth merchant in Delft in the Netherlands, Antonie van Leeuwenhoek, ground tiny glass lenses to check the quality of thread and turned them on everything he could find. In drops of pond water and scrapings from his own teeth he saw swarms of wriggling creatures he called animalcules, the first person ever to see bacteria. His simple microscopes, each a single bead of glass in a metal plate, magnified over two hundred times.
A modern MICROSCOPE uses several lenses and a lamp beneath the slide. Our biology page covers the cells that the first microscopes revealed.
Named after the people who invented them
The PETRI DISH, a shallow round glass or plastic dish with a lid, was designed in 1887 by Julius Petri, an assistant to the great German bacteriologist Robert Koch, for growing bacteria. In 1928 Alexander Fleming came back from holiday to find mould growing on one of his dishes, with a clear ring around it where the bacteria had died. The mould was making penicillin, the first antibiotic.
The cone-shaped conical FLASK is often called an Erlenmeyer flask, after the German chemist Emil Erlenmeyer, who designed it in 1860. Its narrow neck lets you swirl a liquid without spilling it, which a straight-sided BEAKER cannot manage.
Safety first
In a school lab, GOGGLES protect the eyes from splashes and an APRON protects clothes, and long hair is tied back near a flame. TONGS lift hot things, TWEEZERS pick up tiny ones, a CLAMP holds a TEST TUBE steady, and a TRIPOD holds a dish above the burner. A CRUCIBLE is a small, thick pot that can survive being heated until it glows.
Reading the curve
When you measure a liquid in a CYLINDER, its surface curves up at the edges, making a dip called the meniscus. The trick is to read the level at the bottom of the curve, with your eye exactly level with it. A PIPETTE or DROPPER moves small, exact amounts, a FUNNEL and FILTER paper separate solids from liquids, a SPATULA scoops powders, a STIRRER mixes, and a MAGNET can pull iron filings out of a mixture. Our science jobs page covers the people who use all this every day.