Energie
14 cards from across every topic, each citing a source. Tap one to open it in the feed.
- A calorie is really a water temperature.
A kilocalorie is the energy needed to warm 1 kilogram of water by 1 degree Celsius, about 4.2 kilojoules. What food …
- A large share of your energy goes into sorting salt.
The sodium–potassium pump pushes three sodium ions out and two potassium ions in per ATP molecule consumed. Cells …
- How a leaf builds sugar out of air and light.
Chlorophyll captures light and uses it to split water, releasing the oxygen you breathe. The captured energy squeezes …
- How a nuclear plant makes electricity: with a steam engine.
In the reactor, uranium nuclei split and heat a coolant, usually water. That makes steam, directly or through a heat …
- How an LED glows without getting hot.
An incandescent bulb heats a tungsten wire to about 2,500 °C; only around 5 % of the energy becomes light, the rest is …
- How your phone battery stores power: as migrating ions.
A lithium-ion battery has two electrodes, graphite and a metal oxide, separated by an electrolyte. While charging …
- Lactate isn't waste, it's fuel.
When muscles under heavy load need more energy than oxygen can supply, they break down sugar without oxygen and produce …
- More energy out than in? Look for the hidden source.
Two laws of thermodynamics have never been broken: energy does not arise from nothing, and heat flows by itself only …
- No wind turbine can harvest more than 59 percent of the wind.
In 1919 Albert Betz showed that a turbine can't stop the air completely, or it would pile up and nothing would flow …
- The Sun loses four million tonnes every second.
In the Sun's core, about 600 million tonnes of hydrogen fuse into helium every second. Roughly 0.7 % of that mass …
- What a kilowatt-hour really is, in muscle power.
One kilowatt-hour is 3.6 million joules. That lifts a one-tonne car about 370 metres, heats roughly 10 litres of water …
- Why solar cells can never use 100 percent of the light.
A silicon cell only uses photons with energy above its band gap; red and infrared photons are wasted. Blue photons …
- Your brain runs on the power of a dim light bulb.
The brain weighs about 1.4 kilograms, roughly 2 percent of your body, yet uses around 20 percent of your resting …
- Your new fridge got worse overnight – on paper.
On 1 March 2021 the EU replaced the frayed A+++ scale with a clean A to G range, starting with fridges, washing …