Could it power the world? For more than 100 years, scientists have dreamed of creating electricity from the atmosphere. Now it has become a reality.
Scientists make clean energy out of thin air
Frightening lightning: The Ancient Greeks believed that thunderbolts showed Zeus's anger. Glossary
Humidity - The amount of water vapour in the air.
Electricity - A kind of energy that can be controlled and sent through wires. It powers such things as heaters, light bulbs and computers.
Global warming - The Earth is getting hotter due to climate change.
Fossil fuels - Fuels made from decomposing plants and animals, including coal, natural gas and oil. These fuels release carbon dioxide, causing global warming.
Climate change - Long-term shifts in temperatures and weather patterns. Human action is a major cause of climate change.