One of a few ways: 1) from the ground up 2) between the clouds and the ground, and goes both ways 3) some lightning never strikes the ground at all - it goes between clouds Interestingly, when watched in slow motion, lightning looks like it comes down from the clouds. This is called the "return stroke." It produces the light, but is techniquely only a followup to the strike. Hope that helps.

actually after years of research at Yale University, I have concluded that lightning strikes from the ground UPWARDS and that the negativley charged particles in the ground attract opposite charges formed in the clouds, inducing an upwards strike. Hence the term "opposites attract".

Very cool , I would like to hear more on that therory becasue its not the first time i've herd it and yes i've seen lighting strikes in slow motion but mother nature is all powerfull and works in very misterious ways. Is this conclusiv?

Well my friends, what is true here is that lighting does strike....but technically and conclusively lighting first strike from the clouds down to earth. You are actually seeing the light come down, what you see coming back up is the after effect of the air getting charged by these extra electrons. Hope this help the unsure minds...

It can do both depending on the charge of the ground or cloud being positive or negative.

First of all we have to define what is meant by the word "strike." Are we talking about what is seen with our eyes or the nearly invisible leader formation that ionizes the air in the lightning channel from which the charged particles can flow? This is an important definition because they are in fact in opposite directions to each other, and to make matters worse positive lightning was discovered in 1970 which is the opposite to the negative lightning that occurs 95% of the time. To make it simple, negative lightning is the most prevalent and familiar to all of us so I'll describe the process of its formation. Charge separation occurs in the cumulonimbus clouds due to various theories. Normally, the top of the cloud becomes positively charged and the bottom of the cloud becomes negatively charged. This charge separation in the cloud induces a charge separation in the ground with the positive charges accumulating at the highest points on the ground such as trees and tall buildings. As the potential between the negatively charged underbelly of the cumulonimbus cloud and the positively charged high points on the ground increases, leaders start to form from the negative charged underbelly of the cumulonimbus cloud and progress to the positively charged high points on the ground…(it's very important to note at this point that this charge separation will still be induced in the ground even if there are no trees or buildings and its all flat ground...the negatively charged underbelly of the cumulonimbus cloud forces the free electrons in the upper area of the ground that meets the air to move away deeper into the ground thus making the upper area of the ground positively charged...this occurs in high spots such as trees and tall buildings first due to the higher negative charge of the earth)…This leader formation creates the lightning channel by ionizing the air...ionizing the air is a process by which free electrons are released from the outer most valence shells of matter particulates in the space between the cloud underbelly and the ground…If the “strike” is defined as this leader formation then the strike starts from the cloud and moves to the ground and the question is answered for negative lightning which is the most prevalent type of lightning. However, if the highly luminous (most visible) part of the lightning discharge is defined as the “strike” then it moves from the ground up to the cloud. This occurs due to hotter, higher current leaders, called positive streamers, connecting to the positively charged high points on the ground to the stepped leader from the cloud. When this happens the electric current greatly increases. The region of high current propagates back up the positive stepped leader into the cloud with a "return stroke" that is the most lumnious part of the lightning discharge.

both, there are several types of strikes cloud to ground - and + ans vice versa plus cloud to cloud etc

Lighting strikes... from the ground up! I have video to prove it. http://www.popsci.com/scitech/article/2008-10/science-youtube-lightning

did you think about wat you just asked?

Lightning does both. It's just a spark between two poles, and it can originate from the cloud or the ground. In addition to cloud-to-ground and ground-to-cloud lightning, there's in-cloud and cloud-to-cloud. Lightning has been observed from volcanic clouds.

ya mum