I visited the Maryland Science Center and found it very disapointing. First there are no signs at the Center telling you where to park. We eventually parked in a car park where 4 hours cost $27!
Then we found that the Center was very small and alot of the exhibits that you press or touch were not working / broken.
Their security staff are their biggest problem as they are ill-informed about what sections of the Center are on which floors and in some cases just plain rude and clearly need some form of customer relation training.
Above all though we found that we could walk though the entire Center in an hour - the dinosaur section was only the size of an average sized home - but at least some of the exhibits worked!
Certainly not worthy of the name of Science Center.