Tuning forks are primarily used for musical instrument tuning, although electronic tuners now exist and some musicians have absolute pitch. When the tuning fork needs to be tuned, it can be adjusted at the bifurcated parts at both ends: the part with the short tip is adjusted to increase the frequency or the joint between the two forks is trimmed to decrease the frequency; or the weight of the two tines can be adjusted. Even after tuning, the frequency of the tuning fork will still be affected by the change of the elastic modulus of the material. In order to make the tuning fork emit an accurate pitch, it should still be sealed in a place with good temperature and humidity control. Large tuning forks are usually powered by electricity, like a bell, so they vibrate continuously.