The Orlando Science Center is in a gorgeous modern building with huge windows letting in natural sunlight. There are several floors centered around a huge tree and clear pond in the middle of the building, where real turtles and alligators swim below. On each floor are different themed rooms filled with amazing hands-on activities to delight your kids. One of the most fun is a derby race track that slants down- little toddlers keep running back up the stairs with their cars to watch them slide down over and over. There is a very cool magnetic wall where you can arrange PVC pipes in patterns and then let a ball roll down your creation. A sound wave is explained through the use of tiny foam balls that bounce up into wave patterns that show how high or low the note you're playing is. There is a PVC pipe and paddle bat musical instrument like the Blue Man Group uses, and there's a tall tunnel you can sing into and hear the effect of echoes. The Dora exhibit is bright and fun for kids, even as old as seven!

On the bottom floor there are some marine exhibits, an exhibit where you can run as if under the street in the lit-up sewer, a citrus farm exhibit that is a blast for kids as they move the oranges from gadget to gadget, an area to climb in trains and planes, and best of all, a water play area where you can direct your boats in a race over a waterfall or down controlled lanes of flowing water. You feel as if you're outside here, under a tree and in the sunlight coming in the window, which makes it a great place to come on a very windy or rainy day where you won't feel claustrophic or stuck inside.
On the second floor near the railing is an amazing amethyst-filled geode as tall as your kids. There is also a clear statue of a woman- you can press on buttons labelled with organs and that organ will light up.
A highlight of the day is the cinedome theater, included in your admission, where you can watch a 45 minute documentary on a huge dome over your head. The one we saw was on space debris and entertained our 5 year old as much as our 14 year old. The whales movie is lovely as well.
The Science Center is in a lovely wooded park called Loch Haven Park with other museums, such as the Orlando Museum of Art and the Mennello Museum of American Art (which was closed when I arrived during regular open hours, but open the next time I came).
After your visit, drive 9 minutes to Park Ave (like Europe in Florida) to get something to eat.
A decent spot very nearby is Ivanhoe Village where you can eat outdoors at a Greek cafe and then stroll along by the lake.
Nearby is Harry P. Leu Gardens, with large oak trees draped in Spanish moss beside a large lake.

Directions

Orlando Science Center is located at 777 Princeton St, Orlando Fl 32803, call (407) 514-2000.
From Highway 4, take exit 85 for Princeton St and head east on Princeton St for 0.7 miles. Follow the signs to the Science Center Parking. A covered pedestrian bridge leads from the parking lot to the Science Center, which is handy if it's raining.
Admission, which includes IMAX movie, is $19 for adults, $17 for seniors and students, and $13 for kids aged 3-11.
Open Thurs-Tues 10-5. Closed Wednesdays. Also closed Easter, Thanksgiving (fourth Thurs in Nov), Dec 24 and Dec 25. Observatory open first and third Sat 5-9pm.

Click on map for interactive view