Have you considered a vacation which explores science: the flora (plants), fauna (animals), and geology of an area? You will find many interesting and family friendly sites in southern Utah and Arizona.
Bryce Canyon National Park, part of the National Park System (NPS), was established in 1924 and is named after the Mormon pioneer, Ebenezer Bryce. It is best known for its horseshoe-shaped amphitheaters carved from the eastern edge of the Paunsaugunt Plateau in southern Utah. Its famous spires known as "hoodoos" formed when ice and rain wore away the weak limestone of the Claron Formation. It also has slot canyons, window, and fins. Be sure to see: Thor's Hammer, Metate Arch, Sunset Arch, and Natural Bridge. You can see evidence that the Anasazi and Fremont Indians lived in the area of the Devil's Garden in the Grand Escalante Monument nearby.
Canyonlands National Park (NPS) is the largest of the Utah National Parks. Here you may look thousands of feet down to the Green and Colorado Rivers or thousands of feet up to the red rock pinnacles, cliffs, and spires. Be sure to see: Mesa Arch, Monument Basin, Angel Arch, Needles, and The Wall (in the Maze District). The rock art and petroglyphs are thoughtto be 3,000 to 6,000 years old.
Capitol Reef National Park (NPS) was established in 1937 as a National Monument. It became a National Park in 1971. Capitol Reef has sandstone formations, cliffs, canyons, and a 100 mile long bulge in the Earth's crust known as the Waterpocket Fold. Be sure to see: The Temple of the Sun and The Temple of the Moon (both in Cathedral Valley), as well as Chimney Rock, and Hickman Bridge.
Arches National Park (NPS) has the world's largest concentration of natural stone arches. The 73,000 acre red arid desert has oddly eroded sandstone fins, pinnacles, spires, balanced rocks, and 2,000 arches. Be sure to see: Balanced Rock, Skyline Arch, Double Arch (all 3 in the Windows Section), as well as Fiery Furnace, and Delicate Arch.
Zion National Park (NPS) was established in 1919 and is the oldest of the Utah National Parks. Be sure to see: the slot canyons (such as The Narrows), the towers, monoliths, the Great White Throne, Kolob Canyons, and 6,500 foot high Watchman Peak.
Grand Canyon National Park (NPS) was established in 1919. It is one of the 7 natural wonders of the world.
The Painted Desert is 93,533 acres extending from the Grand Canyon to the Petrified Forest. The colors are amazing. Your best chance for photographs will be either at sunrise or sunset. Be sure to purchase some post cards because it is very difficult to adequately capture the colors.
Petrified Forest National Park (NPS) was established as a National Monument in 1906. It has one the best geologic fossil records of the Late Triassic.
Arizona Sonoran Desert Museum near Tucson is a zoo, botanical garden, and natural history museum. You can see many species of cacti as well as animals characteristic of the area.
Old Tucson Movie Lot is a 320 acre site which has been used to film many movies and TV shows. Many John Wayne films were made here as well as the High Chaparral TV show. There are 75 building on the lot. Though this site isn't about science, it is very near the Arizona Sonora Desert Museum and its a wonderful family friendly experience.
You may wish to check the National Park Service website as well as Arizona and Utah Tourism sites.