Lightning: a flash of light in the sky caused by an electrical discharge between clouds or between a cloud and the Earth's surface. The flash heats the air and usually causes thunder. Dictionary.com

See lightning strikes in real-time 
https://www.lightningmaps.org/?lang=en#m=sat;r=0;t=3;s=0;o=0;b=;n=0;

Safety Tips: http://www.weatherwizkids.com/weather-safety-lightning.htm

Test your weather skills
​and knowledge...

Estimate the distance of lightning http://cimss.ssec.wisc.edu/wxfest/Lightning&Thunder/ltg.html

Make a thunderstorm  http://cimss.ssec.wisc.edu/wxfest/MakeTstorm/tstm.html