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The air inside a lightning bolt can reach roughly 30,000°C, about five times hotter than the visible surface of the Sun.

Atmospheric physics

Science

The story behind the card

Lightning starts inside storm clouds, where strong rising air makes small ice crystals collide with soft hail pellets called graupel. The collisions separate electric charge, usually leaving the top of the cloud positive and the lower part negative, until the difference is great enough for a spark to jump within the cloud, between clouds or down to the ground. The current heats a channel only a few centimetres wide in millionths of a second, so the air expands explosively and sends out a shock wave that we hear as thunder. Light reaches us almost instantly, but sound covers only about a kilometre every three seconds, so counting the seconds between flash and thunder and dividing by three gives the distance in kilometres.

Türkçe oku
Şimşeğin geçtiği ince kanaldaki hava yaklaşık 30.000 °C'ye kadar ısınabilir; bu, Güneş'in görünen yüzeyinden kabaca beş kat sıcaktır.

Şimşek, fırtına bulutlarının içinde başlar. Güçlü yükselen hava akımlarında küçük buz kristalleri, yumuşak dolu taneleriyle çarpışır. Bu çarpışmalar elektrik yüklerini ayırır: Bulutun üst kısmı çoğunlukla artı, alt kısmı eksi yüklenir. Fark yeterince büyüyünce bulutun içinde, iki bulut arasında ya da buluttan yere bir kıvılcım atlar. Akım, yalnızca birkaç santim genişliğindeki kanalı saniyenin milyonda biri gibi kısa sürelerde ısıtır; hava patlarcasına genleşir ve bir şok dalgası yayar. Gök gürültüsü dediğimiz ses budur. Işık bize neredeyse anında ulaşır, ses ise yaklaşık üç saniyede bir kilometre yol alır. Bu yüzden şimşekle gök gürültüsü arasındaki saniyeleri sayıp üçe bölerseniz, fırtınanın kaç kilometre uzakta olduğunu kabaca bulursunuz.

Sources and further reading

Background reading: Lightning
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