I have been tracking the grand opening of the new National Children's Museum since giving birth to my kid. I remember my experiences at the old museum on H street and couldn't wait to share them with my kids. It is about the size of a restaurant and one level. The cost is $10 per person for anyone over the age of 12 months. It's basically a big "playseum" and nothing really to "learn." There are pretend play stations - world market, dress up, fire tation, pizza making station, cranes, books, arts & crafts, etc... Very similar to the playseum in Bethesda. I don't suggest purchasing a membership...you will be disappointed. I heard many parents complaining that $155 went down the drain as they purchased sight unseen!
On the flip side, it is nice, clean, bright and new! We spent 1.5 hours in there and pretty much visited all the areas, watchd a skit in the theater, and enjoyed the new years eve "parade."
I just remember doing so much more in the old museum, such as makng real newspapers, wax objects, and real food. I believe it was much much bigger too. The new museum is opening an outdoor area in 2014 that seems to be more educational..per the website.
Go with the right expectations and you will enjoy it... I would say it is more appropriate for 5-6 and under.
Hope this helps!
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