A laboratory experiment need not take place in a formica sided area. It has to do with the control an experimenter is taking over the study. An experiment is an investigation in which a hypothesis is scientifically tested. In an experiment, an independent variable (the cause) is manipulated and the dependent variable (the effect) is measured; any extraneous variables are controlled.
This has to be so that experiments are objective. The views and opinions of the researcher should not affect the results of a study. The aim is to make the data more valid, and avoid contamination by interfering variables, such as distractions for the subjects, and from bias.