Science
Energy
Procedural
12–13 yrs
Efficiency, Sankey diagrams, and work done
效率、桑基图与做功
Description
Calculate energy efficiency as the ratio of useful output energy to total input energy, construct and interpret Sankey diagrams, and calculate work done using work = force × distance
Mastery Evidence
- Calculates efficiency as a percentage from given input and useful output energy values
- Draws a Sankey diagram to represent energy transfers in a device, with arrow widths proportional to energy amounts
- Uses W = Fd to calculate work done when a force moves through a distance
- Identifies which energy transformations in a Sankey diagram are useful and which are wasted
Assessment Prompt
If your child heard that a light bulb is 10% efficient and uses 60 J of energy, could they work out how much of that energy actually becomes light — and where the rest goes?
