T<span>hese changes in </span>energy<span> cause the changes of states of </span>matter. In a solid, particles have<span> less </span>energy<span>, are tightly packed together (more dense) and do not move very much. Solids </span>have<span> a definite shape and volume. In a liquid, particles </span>have<span> more </span>energy<span>, are less tightly packed (less dense), and can move freely.</span>