Regardless of your age, you'll surely enjoy the interesting scientific exhibits and displays at Kiseki Museum of World Stones.
You'll be spoiled for sightseeing choice in Fujinomiya. Kiseki Museum of World Stones is a good place to begin here, but there are many other fine sights to consider. Mt. Fuji World Heritage Center, Taiseki-ji Temple, and Makaino Farm are not far from the display of scientific achievements and will fill in your day nicely.