Our cup holds the heat inside because we used foil, which reflects heat so it won’t go out of the cup. Also, we use black felt so the outside heat will come in and give heat to the water inside. In the inside, we out some cotton so that it will prevent heat loss. We would not hot glue somethings inside because the water was so hot that it melted the hot glue. The hardest thing for our project is to control our self to use less hot glue and to let the lid stay down. Our quality was not bad because it worked well and our materials didn’t break or fall apart. My team was proud that we were able to cut the foil without letting it break apart while cutting it, also our insulator stops heat transfer outside.