From the experiment in the lab. Devices, measuring instruments, or who make observing. With that, the trial results are staggering. Therefore, the trial results may not match the theory too much.
From the laboratory experiments Measurement Or conducted Contribution to the results of the experimental error. Therefore, the results obtained may not be exactly as much theory.
From the laboratory experiment instrument or an experiment Has made experimental results with an error Therefore, the results showed that may not meet the theory very well