I must disagree with this analysis. I have watched every episode, including out-takes and a lot of extra footage. They do indeed do controls and a large number of trials for their experiments. They constantly complain of the limits imposed by the 1-hour time requirements. It is clearly not lab work as it really exists, but as someone who has done real grinding work in the lab, I don't think that there is any better way of killing a love for science in little kids than trying to convince them that repeating an experiment 100 times is fun.
Ages 2 and 5 are a time for wonder and magic. It is not the time to wow them with the scientific method. It works better than any other way of knowing, but it is *not* sexy.