These notes describe how waves transport momentum and energy without the net movement of particles from one end of the system to another. From basic principles, we expect waves to conserve momentum and energy (as well as angular momentum). What is not so clear upfront is that a picture of flow of these quantities from one neighboring point to the next accounts for this conservation. The fact that energy and momentum indeed flow from one point to the next allows us to understand how waves propagate their influence across space.