Yes learning can be fun in Disney World.  It's all here - history, geography, culture, science, math, economics and more.
Epcot has many fun opportunities starting with the pavilions of 11 countries at World Showcase. Sign up for Kidcot  then make your way around the world stopping at the Kidcot fun stops. It is a little like a scavenger hunt. Your child can collect a stamp in each country as they learn from an international cast member about their culture, food, dress and how to say "hello" in their language.
They younger ones can color a picture or learn a craft.

Agent P's Secret Agent Mission is getting great reviews from the kids so don't miss this one. Start by going to a recruitment station located at either Odyssey Bridge, Norway or Italy pavilions or near International Gateway.     

You will receive your assignment and get your interactive hand held evil detector device that will guide you on your mission (2-4 agents can share this). Clues are in various pavilions in World Showcase. Each mission lasts 30-45 minutes

The American Adventure show in the American pavilion has Ben Franklin and Mark Twain telling the story of America beginning with the pilgrims 

 through World War II. 

In Future World they can learn about science at Mission Space. Be forewarned that this ride can cause motion sickness.
The Universe of Energy teaches about fossil fuels, energy and conservation.

The Circle of Life show in the Land Pavilion teaches about environmental protection. Also here is The Living with the Land ride which is an indoor boat ride through greenhouses where they can see aquaculture tanks and see plants growing without soil (hydroponics).                  

You can have fun with several hands-on activities in the Innoventions Pavilion and learn about new technologies.

Nemo and his Friends have their own pavilion where the kids can learn about aquatic life with marine exhibits. Don't pass up the Turtle Talk with Crush. It is a lot of fun.                                      
                                                

At the Test Track you can create your own virtual concept vehicle and then go for a high octane ride. This thrill ride requires a child to be 40 inches tall.

One of my favorite rides is Soarin'. Again you must be 40 inches tall. You feel like you are flying above California and you can even smell the orange groves. The lines here are usually long so use a fast pass  here.

Spaceship Earth (aka as the golf ball) has a ride teaching about the history of communication. Kids like going up "in the ball". This is at the entrance to Epcot so is a good one either at the start of the day or the end of the day.