Conservation of Energy: Multiple Stages

No

Yes

$chemical \rightarrow electrical \rightarrow sound$

$electrical \rightarrow heat +light$

$elastic \space potential \rightarrow kinetic \rightarrow heat$

The conservation of energy applies to energy transfers with multiple stages as well as single energy transfers.

The conservation of energy applies only to direct energy transfers.

The conservation of energy applies only to energy transfers which involve multiple stages.

Histogram

Sankey Diagram

Flowchart

In the same diagram, we draw energy transfer arrows in all 4 directions.

The thickness of the input arrow reduces with each stage of the transfer to show that some energy is wasted at each stage.

Multiple Sankey diagrams are needed to describe an energy transfer involving more than one stage.

Light bulb.

Battery

Electric milk float

No

Yes

After each transfer, the total thickness of the $\rightarrow$ and $\downarrow$ arrows is less than the thickness of the first energy input arrow.

After each transfer, the combined thickness of the $\rightarrow$ and $\downarrow$ arrows is the same as the thickness of the first energy input arrow.

The thickness of the $\rightarrow$ arrows and the thickness of the $\downarrow$ arrows at every stage is the same as the thickness of the first energy input arrow.