Hello, my name is Malcolm. I am here at the Piano Workshop at Reigate, Surrey, UK for About.com and I am here to talk about how a piano can go out of tune.If there is too much moisture in the air, then all the parts can swell up causing hits to loosen off, making the piano go flat. If it is too dry, then the wood tightens, making the strings go tight, then it will go sharp.The amount of humidity in the air, which is the amount of water in the air, it needs to be around 50 percent-ish, it can be a little bit more or a little bit less. We have a humidity gauge here on top of our piano, which is a good way of measuring it.The other thing that can affect the piano is the temperature. And again, on here we have got a hydrometer and a thermometer on the same gauge so you can keep an eye on it. Ideally it should be around 50. And again, that can affect: too hot, it can go flat, too cold, it can go sharp.Another reason a piano can go out of tune is through heavy play. This is when the piano's notes are played really loudly, as this will stretch the strings over time. Thank you for listening for some tips on how a piano goes out of tune.My name is Malcolm, I am at the Piano Workshop at Riegate, Surrey, UK, for About.com.