Chemistry neophytes use a temperature probe to assess the change as five different liquids evaporate. The implantation section suggests that they take readings every five seconds for a total of four minutes. They graph the data, look up molecular masses, and then determine whether or not there is a relationship. It seems that five-second intervals would be difficult to manage when testing five different liquids, and that a four-minute collection time might not be enough to see a significant difference.