Hello! I'm building a metallophone for Science Olympiad this year, and I encountered a problem. Since the length of the pipe determines the frequency/pitch, I sawed the pipes to different lengths for different notes. The problem I was having, however, was that when the temperature changes, the pitch of the pipes changes as well. It isn't extremely significant, like an entire note off, but it's noticeable to a person trained to recognize pitch well. Is there a way I could minimize the effects of temperature? Thank you!