Today's NY Times features an article about a conflict among educators over online lab courses. Universities are debating whether to accept virtual lab courses as a substitute for real Freshman science labs, especially when it comes to AP credit.
Online schools allow students to do virtual pig dissections, virtual DNA gels, and virtual chemistry experiments, and defenders of the vitrual lab courses argue that their students do just as well, if not better on AP exams. If your goal is a high exam score, then I don't question that these virtual labs can help students effectively learn the concepts. But science is more than just concepts, and virtual labs can never take the place of real labs in seriously training scientists.
Learning to be a scientist is much like an apprenticeship - you could never learn to be a master chef, violin maker, or serious gardner if you tried to learn all your skills in an online simulation, even though that simulation might help you learn the concepts involved. You can't learn to be a serious mechanical engineer if you never set foot in a machine shop. Experimental science requires something like a green thumb - a hard to desciribe ability to use your tools with just the right touch. Many experiments are technically challenging, and require dexterity and experience to do them well - that is, reproducibly. (And, going back to the NY Times article, the 'kitchen chemistry' they describe is no substitute. Kitchen chemistry is usually just a bunch of magic tricks; it doesn't come close to teaching kids what real experiments are like.)
Actually, I think this point is generally true of all online learning that tries to be a substitute for a real univerity education. All serious scholarship, whether it involves lab work or not, requires an element of apprenticeship to learn. At most, virtual courses can help students learn the basics, but a complete online university is more like a technical school or certification program, not a real university.
But what about kids in poor schools that can't afford to have serious science labs for their AP courses? In those cases, a good virtual lab is probably better than a poor or nonexistent real lab. Universities have to decide, whether all of their graduates need that kind of lab experience. For students graduating in science or medical fields, the answer is an unequivocal yes. For the others, I don't know the answer. But, in light of the fact that the US is producing fewer and fewer home-grown scientists, a great hands-on science lab can be a great way to get the AP students who took these virtual lab classes interested in a science career.