The answer is both. Cloud-to- ground lightning comes from the sky down, but the part you see comes from the ground up. A typical cloud-to- ground flash lowers a path of negative electricity (that we cannot see) towards the ground in a series of spurts. Objects on the ground generally have a positive charge.
How is lightning formed?
Lightning is a form of electricity . How does this “electricity” form? Image above: Ice crystals and water droplets bump together and move apart to cause electricity. Credit: NASA You need cold air and warm air. When they meet, the warm air goes up.
How lightning and hail are formed?
Thunderstorm clouds form when warm air currents rise above the Earth’s surface creating cumulonimbus clouds. These clouds produce rain, lightning, hail and occasionally tornadoes.
Lightning bolts during a thunderstorm. Lightning is the result of hot air near the surface of the Earth heating up during warm days. The warm air begins rising in an updraft that carries the warm air high above the surface of the Earth. The warm air cools as it rises into the atmosphere.
One inquiry we ran across in our research was “What happens when a person is struck by lightning?”.
With a power of 300 kilovolts, lightning can heat the air up to 50,000 degrees Fahrenheit. This combination of power and heat can cause serious damage to the human body. Being struck by lightning may lead to burns, rupturing of the eardrum, eye damage, cardiac arrest, and respiratory arrest.
How does hail form in clouds?
Hailstones form in most tall, cumulonimbus storm clouds that reach the colder upper atmosphere, but not all hail survives after it is out of the thunderstorm. A few outer layers frequently melt when the hail mixes with other precipitation, such as snow and rain.
The ideal conditions for hail are tall clouds that reach high into the atmosphere, many swirling updrafts such as in a tornado and cold temperatures within and beneath the storm. Hail may form during severe thunderstorms. A hailstone begins to form as an ice nucleus, a small cluster of supercooled water droplets or clumps of snow.