In science, a title usually tells the reader what the subject of the experiment and the key research variables are, and it often gives an indication of what research methodology was used. Titles are especially important to scientists because articles are typically indexed according to key words that come from the title. So when scientists are searching for research articles, it is those key words that lead them the articles they need. It's necessary, then, that titles be fully informative about the content of the report. A variable is what is measured or manipulated in an experiment.
Variables provide the means by which scientists structure their observations.