We visited with our 4th grader studying California missions and our 6th grader. The museum had some interesting items on display, but the whole top level was a display about the founding of the museum itself...not particularly relevant to Father Serra, the Missions, or important events in California history. The kids liked the hands-on archeology room, though. And they loved the view from the bell tower. The cost of admission was not much, so I wouldn't call it a waste. But if time in San Diego is limited, I'd suggest visiting the Mission and Old Town. Visit this museum if you have extra time, or just want a nice uphill hike from Old Town to give your 4th grader some exercise!