Good Morning Mean Mom. We have been taking our DD (14) to Epcot since she was 6 and this is her and our favorite of the parks. If you have the time, I would allow two days to really enjoy and take everything in. Since your kids are sciency, they will likely enjoy the East and West Innovation pavillions. They have sections where you can do things such as make paper and try out new games. Also, take the boat ride in The Land that goes through the green houses and take in Soarin' and Test Track. Later in the day start checking out the countries and shows in World Showcase. Each country has a movie or an act. For instance, China has both a movie and a Chinese acrobat troupe that is fabulous. England has a Beatles tribute band, Morocco has a belly dancer and a rock band. Oh, and they would probably love the candy lady in Japan. Get to her show a little bit early so your kids are up front and hopefully one of them will get picked to tell her what kind of animal to make (that they can keep).
Epcot is a great time. I hope you and your kids enjoy!