Thomson<span> is the scientist who designed an experiment that enabled the first successful detection of an individual subatomic particle. </span>J.J. Thomson<span> (Sir </span>Joseph John Thomson<span>, 1856-1940), who demonstrated in 1897 that "cathode rays" consisted of negatively-charged particles, later named electrons.</span>
A change in temperature or color are two signs that a chemical reaction has taken place.
