What makes a TED talk good

 I believe there are three things neccisary for a good Ted talk, 1. is a interesting and relatable subject matter, 2. Is keeping the audience interested in you either by entertaining them or using visuals 3 is a take away that makes the audience go "oh wow never thought like that before"
       The first one is kinda tough because your subject must be interesting enough to talk about without constantly repeating yourself or bore the audience. It's gotta be exciting to the audience, something fresh and new that they haven't thought about much or not at all. At the same time it has to be relatable, if your gonna talk about quantum physics don't talk about formulas and rules and actual Science, you gotta Paint a word picture. For instance if you were gonna talk about how the speed of light slows down time if you get near that speed you don't quote a bunch of numbers at the audience, you talk about how if a train had a track that circled the earth and could go the speed of light everyone on that train would experience time differently, a time bubble if you will and when they got of that train having been on it for a few hours they would be 100s of years into the future.
       Secondly you must entertain your audience, you could do this numerous ways. One way is the word picture as I said before, humor is a good way, audience interaction is good too but usually that dies off when the speaker gets into the meat of their speech,  or appealing to the emotion of the audience. Visuals are important too but if you do not need them you don't hafta use them. Entertaining the audience is less about keeping interested in what your saying and more about stopping them from being bored. As long as you keep them paying attention you should be able to at lest leave them with the take away which is your only lasting impression on the audience. No one will remember your statistic about incarnation rates in America but they will remember you saying that being reborn is the best experience of your life. This leads us to our third part.
       Which is the take away. The take away is vital, it makes the audience think for just a moment about something they never have. It's the main reason anyone bothers to watch TED talks cause if people just wanted to know about a subject, they'd look up the subject the speech is about and research it themselves. No, they want a spoon fed "wow never thought like that before" feeling that makes them feel good for about ten minutes. Your take away hasta sound impressive and reflect on what your speech was about. Use clever word play, big words,  the works. You gotta make this the most amazing thing that was ever said about anything. Once you figure that out you got yourself a speech. Now your ready to say it to the masses.