Yes, there's a huge difference between the amount of information that 19th C. and 20th C. kids had access to, but then this is a broad generalization and it requires qualification. In fact I'd argue that some 19th C. kids (albeit few in relative numbers) would have had access to more information than many of their 20th C. counterparts.

Broadly, the reason for why some 20th C. kids would have had access to less information is that they were more protected from dangers than those in 19th C. (and in some ways that's problematic when it comes to learning). Also, clearly, the types of information available in each era would have been different—and this difference would have been accentuated depending on which part of each century we're referring to.

The 19th C.—being the height of the Industrial Revolution—change came thick and fast, so it's almost superfluous to say kids' knowledge of electricity at the turn of the 20th C. would have been much greater than at the beginning of the 19th however this difference wasn't anywhere near as stark at other times throughout the 19th C.

This is best illustrated by example and for that I'll use a book published in 1858 by Elisha Noyce titled The Boys Book of Industrial Information. https://archive.org/details/boysbookofindust00noyc

So by 1858 enough information was known about electricity to include technical aspects about it including its industrial applications such as electroplating, p129, and the telegraph, pp273-280 in a kids' book. I'd also posit that some 20 years later (by say 1880) with the coming together of electrical engineering—telephone, electric motors, generators, transatlantic cables, theory by Maxwell, Wheatstone et al, that much more information about the subject would have been available to kids.

Noyce's book was a true eye-opener to me when I came across it some two to three decades ago, so much so that I now truly regret not having a copy of it as a kid. I know I would have gained a great amount of useful knowledge from it despite the fact that it was published a century before my time.

Whilst I had access to more modern texts they didn't provide the information in such a useful and meaningful way. Moreover, much of that information is still very relevant and valuable today. For instance, I refer you to pp57-58 on the dangers of lead and lead poisoning, therein Noyce issues a stark warning especially so with respect to white lead as used in paint.

(This advice would have been invaluable to boys who would have gone into industries where they'd be exposed to such dangers. It also infomes us that knowledge of and concerns about bad and dangerous working conditions of the era may have been better understood at the time than some modern history books would have us believe.)

Keep in mind this warning was in a book for boys written to provide them with practical and useful information—not published in some erudite scientific publication. The fact that by 1858 the dangers of lead had filtered down not only to ordinary people but also to their kids makes the failure of governments and those knowledgeable of the facts to act in a decisive way over the forthcoming century all the more tragic (when I first read Noyce's warning I was quite horrified that so little action had been taken until recent decades).

As you see, with actual information to hand things seem a little more nuanced.