Building an Energy Converter
Aligned to HS-PS3-3 — Next Generation Science Standards.
What this lesson teaches
Every device that does work converts energy from one form to another, but never at 100 percent because some energy always escapes as heat. Efficiency is the useful energy out divided by the total energy in. Good design increases the useful share while working within cost, size, and material limits.
Worked example
A small motor draws 50 J of electrical energy and lifts a weight, doing 30 J of useful mechanical work; the other 20 J leave as heat and sound. Its efficiency is 30/50 = 0.60, or 60 percent.
Practice questions
- Name the input energy form and the useful output form for a solar cell.
- A generator turns 200 J of motion energy into 140 J of electrical energy. Calculate its efficiency and state where the missing energy went.
- Design a device that converts falling-water energy into electrical energy, and describe one change that would raise its efficiency.
Watch the lesson
Every lesson comes with a video taught in English and Spanish — the same video the QR code in the printed workbook opens.
▶ Watch this lessonEn español
Construir un Convertidor de Energía
Todo dispositivo que realiza trabajo convierte energía de una forma a otra, pero nunca al 100 por ciento porque siempre se escapa algo de energía como calor. La eficiencia es la energía útil de salida dividida entre la energía total de entrada. Un buen diseño aumenta la parte útil mientras respeta límites de costo, tamaño y materiales.
Ejemplo: Un motor pequeño consume 50 J de energía eléctrica y levanta un peso, realizando 30 J de trabajo mecánico útil; los otros 20 J salen como calor y sonido. Su eficiencia es 30/50 = 0.60, o sea 60 por ciento.
More Energy lessons
Teach this lesson today
An AI tutor that guides with questions instead of just giving answers — all K–12 core subjects, every child in the family.
Start free — no card required