There is actually quite a few things you can do to understand that the earth is flat at home. Just by thinking about it and looking at things in the real world. I've personally thought through 2 if I remember correctly. The earth is round. There are also the little proofs (like in this day and age you can ask people on any part of the planet what time it is and they'll tell you quite different times from yours ) And then there are the big experiments and the like (flying to space for example)... I'll try and look them up later.