This question comes to us from Nora in NY and is also ranked as one of the most adorable questions we’ve ever received. Thanks for having your mom send us your question Nora!
Before we answer this question we need to answer another question: What is electricity?
As we’ve mentioned in previous articles (such as our article How Old Is The Earth and How Do We Know It?), everything that you see is made up of atoms, which are composed of protons, neutrons and electrons. The protons and neutrons sit in the center of the atom, in what we call a nucleus. The electrons meanwhile, move around in a cloud that surrounds the nucleus. Electrons are negatively charged. This is a very simple representation of an atom:
While this is an oversimplification, and not exactly how atoms looks or how electrons would behave, it gives us an idea on how the electrons surround the nucleus.
In reality the atom probably looks closer to this, where the electrons have some probability to be at any given point in the blue green could around the nucleus:
What we mean by a probability is that the electrons aren’t necessarily spinning around the nucleus (quantum physics is weird), but that gets a bit complex and perhaps we’ll cover that in another article. For now, the main point is to understand that the atom has electrons that are somewhere around the nucleus and that these electrons are not completely bound to the atom and can be moved and stripped away.
Ok, so what do these electrons have to do with electricity? Simply put, electricity is the movement and flow of these electrons. Now if electricity comes from the movement and flow of electrons, let’s look at where lightning comes from. To understand that, let’s first look at a rain cloud.
In a rain cloud, water droplets get brought up to higher altitudes by winds, and when they get high enough, and the temperature is low enough, these rain droplets freeze and start to fall again like so:
As they are falling, frozen droplets move past the rain droplets on the way up, and they grab some of their electrons. As the temperature increases on their way down, the frozen droplets melt and re-form rain droplets but this time they have a lot more electrons. This creates a charge imbalance where there are more electrons at the bottom of the cloud than at the top.
When there is a big enough imbalance and there are enough electrons collected in one area, the electrons can jump in the form of lightning to balance out the charge. The electrons can jump in a variety of ways: from the bottom of the cloud to the top, from one cloud to another cloud or from the cloud all the way to the ground.
Regardless of where they are jumping to, we see this as lightning. And that is how the sky gets electricity!
You can do a simple experiment at home and safely make your own mini lightning. One option is to take a few blankets or towels and throw them in the dryer (blankets or towels with fine fibers such as sherpa, wool or microfiber work the best). Make sure you do not put in a dryer sheet because we’re trying to build static electricity. Leave them in for about 20 minutes and then open the dryer. Try to find two of the towels or blankets that are stuck together, and then bring them into a very dark room (the darker the better). Get at eye level with the blankets so you will be able to see in between the two layers when you pull them apart. Pull them apart quickly and you should see tiny little lightning bolts where the electrons are jumping trying to balance out the charges.
Just like in the cloud, as the fibers are moving around in the dryer, they are pulling off electrons and creating a charge difference. When you pull the two apart the electrons jump trying to balance out the charges. Lightning is the same thing on a much, much, much larger scale.
And now that you know how lightning works, you’re on your way to becoming the next Thor: God of Lightning (or was he the god of hammers?), all thanks to Science! Thanks for the question Nora!