What am I doing right?

As you can tell the class is engaged almost everyone is working on gathering data and improving their setups. The sophistication has grown in a day. It makes me wonder what did I do to get it right? By no means am I complaining. I think it's cool. We have had some creativity to day. Some groups are testing different amounts of water on the track. Another group is doing drag by using sails on the cars. I am still in awe on how well it's going.