Notice the five types of bag materials. LDPE, HDPE, and Mylar are types of plastic, while latex and neoprene are types of rubber. Find the combination of water and powder that produces the maximum temperature increase. To maintain a controlled experiment, use the same amounts of water and powder in each bag. Record data below: Type of material LDPE HDPE Latex Mylar Neoprene
Maximum temp. (ºC) 67ºC 65ºC 65ºC 68ºC 54ºC

Required:
a. Which pack material got the hottest?
b. Why do you think the outside of this pack got hotter than the other ones?