Many modern experiments involve using a microwave oven to produce small rising glowing balls, often referred to as plasma balls. Generally, the experiments are conducted by placing a lit or recently extinguished match or other small object in a microwave oven. The burnt portion of the object flares up into a large ball of fire, while "plasma balls" float near the oven chamber ceiling. Some experiments describe covering the match with an inverted glass jar, which contains both the flame and the balls so that they do not damage the chamber walls. (A glass jar, however, eventually explodes rather than simply causing charred paint or melting metal, as happens to the inside of a microwave.) Experiments by Eli Jerby and Vladimir Dikhtyar in Israel revealed that microwave plasma balls are made up of nanoparticles with an average radius of 25 nm (9.8 × 10 inches). The Israeli team demonstrated the phenomenon with copper, salts, water and carbon.