Pop your popcorn according to package directions. Transfer it to a large brown paper bag, sifting out the kernels. Set aside.In a medium microwave-safe bowl, mix the sugar, butter, and corn syrup. Microwave on high for one minute, stir, and then microwave for one more minute, stirring again.Add the baking soda, mixing completely, and then quickly pour over the popcorn. Shake the bag vigorously, so as to coat the popcorn with caramel.Fold the top of the bag over a few times and then microwave for one minute. Remove the bag {It's hot! Be careful.} and shake the bag and return to the microwave. Microwave for one more minute and then shake again. {It's really hot this time, so be really careful.}Pour popcorn onto wax paper and let cool completely, breaking apart as desired.