If you are looking at a stream that has dried up are you looking at a system in equilibrium?

Answer 1

• Equilibrium is a condition in which all forces are balanced by others, resulting in a stable system. Conditions on our planet can be stable for long periods of time because opposing forces or processes balance one another.
• An Earth system or process is in equilibrium when the amount of stuff, energy, or force that is added to the system is exactly balanced by the same amount of the stuff, energy, or force leaving that system. Think of Earth processes or systems as bank accounts, in which the stuff going in is the same as the stuff going out. They're balanced.
• Convection is a process in which heat is transferred through a material as a result of different densities. Heat from the sun and heat from Earth's interior drive the motions of the atmosphere, hydrosphere, and geosphere.
• Density, the amount of mass per unit volume, is a measure of how much stuff is in a specified volume. For example, one square kilometer of land is considered densely populated if, say, one million people lived there - all crammed together like sardines. If only two or three people lived in the same square kilometer it would be much less densely populated. It's the same volume (amount of land) with less substance (people) inside it, so it's less dense.
• Differences in density in materials is what drives convection. Density is a property that changes when a substance is heated or cooled. The temperature of the substance will alter the volume, making the same mass take up a different volume. The larger the volume, the less dense the substance is. Hotter material rises. Cooler material sinks and takes the place of the hot material that just took off. It's a cycle.