Your answer is radio waves
Mercury expands when it is heated. This process is called thermal expansion.
Sounds travels most rapidly in solid objects, especially those that are dense. These objects have closely packed atoms, and energy that is traveling in vibrations (the sound) can easily pass between the touching atoms.
Shure what you need help with
An ion is a charged atom or molecule. It is charged because the number of electrons do not equal the number of protons in the atom or molecule. An atom can acquire a positive charge or a negative charge depending on whether the number of electrons in an atom is greater or less then the number of protons in the atom. An example is Iron (III) , Iron (II) , lithium, and hydrogen.
