Energy transformation – useful energy, waste and conservation
Integrated ScienceEnergyAges 11–12
Use it with your class: students open it from a link or a QR code, with no account needed.
Next in Energy
Choose a device (incandescent bulb, LED lamp, electric fan, electric kettle, moped, solar panel): energy particles flow from the source into the device and split into a useful share (green) and a wasted share (red, usually heat) according to its efficiency. The energy bars and running totals show that total energy out always equals energy in; drag the efficiency slider to compare energy-saving and energy-wasting devices.
Lesson: Forms of energy; energy transformation; wasted energy; conservation of energy; energy saving
What it shows
Every device transforms energy from one form into another, but only part of the output is in the form we want. This model sends a stream of energy particles from the input (electrical energy, chemical energy in fuel or light) through the device and splits it into useful energy and wasted energy, mostly heat dissipated to the surroundings. Efficiency is the useful energy output divided by the total energy input. Whatever the efficiency, the running totals show useful plus wasted energy equal to the energy supplied, illustrating conservation of energy and why high-efficiency devices save energy.
How to use
Pick a device with the buttons under the picture, starting with Incandescent bulb, and read the useful and wasted shares at its typical efficiency. Then switch to LED lamp and compare. Drag the Efficiency slider to try your own values and check that the conservation line at the top always balances. Press Reset to clear the running totals before each comparison, and Pause to read the numbers.
Parameters you can change
- Device Incandescent bulb, LED lamp, Electric fan, Electric kettle, Moped (petrol engine), Solar panel
- Efficiency (0 = device's typical value) 0–100 %
- Energy supplied per cycle 50–500 J
- Energy-flow speed 0.5–3 ×
- Show energy particles
Questions to explore
- For an electric kettle, which energy transfer is useful and which is wasted?
- Where does the wasted energy go, and does the total amount of energy decrease?
- Why does an LED lamp need less electrical energy than an incandescent bulb to give the same light?
