Wedges of an orange generate enough current and electrical juice – 3.5 volts – to power an LED. The fruit’s citric acid helps electrons flow from galvanized nails to copper wire in this 14-hour exposure. This image was published in September’s Visions of Earth, a trio of photos that appear in each issue of National Geographic. (Photo by Caleb Charland/National Geographic)

Anti-pollution protesters wearing traditional costumes and contemporary gas masks ride bicycles in the Qingming Grand river park in Kaifeng, Henan Province, China on January 1, 2017. The Beijing Municipal Environmental Protection Bureau extended an “orange alert” for heavy air pollution for three more days. (Photo by SIPA Asia/Rex Features/Shutterstock)

Aerial view of tourists cooling off at a water park in summer on June 27, 2023 in Zhengzhou, Henan Province of China. Zhengzhou Meteorological Observatory on June 27 issued an orange alert for high temperatures. (Photo by VCG/VCG via Getty Images)

Men eat oranges from a push cart along a road as a vehicle travels past them in Karachi January 22, 2015. (Photo by Akhtar Soomro/Reuters)

In this photo taken on March 11, 2019 an Afghan street vendor selling oranges waits for customers on a rainy day on the roadside in Jalalabad. (Photo by Noorullah Shirzada/AFP Photo)

Almost two years old male baby orang-utan Dalai looks on in the zoo in Dresden, Germany, 30 March 2017. Dalai was born to mother Daisy in June 2016. (Photo by Filip Singer/EPA)

Buildings in Lujiazui financial district are seen shrouded in fog amid an orange alert for heavy fog in Shanghai, China on January 31, 2024. (Photo by Xihao Jiang/Reuters)