Derek Owens is a high school (and homeschool) math and science teacher who uses videos to explain basic concepts from his science classes. These videos are great for teachers’ background knowledge. It’s possible that they could be used in some adult ed classes, but I see their main usefulness in building our knowledge as teachers and improving our ability to explain concepts in science. Owens uses a blackboard to illustrate the forces he describes in his videos and explains concepts in a very clear way. The videos from Owens are a resource that it would be hard to stumble upon, but these videos have been really useful for our curriculum writers who are looking for ways to explain electrical charge to students as part of a science curriculum on energy and matter.
The 3-video series on lightning is an engaging example of Owens’ style. The pace of the description moves slowly while he draws a scene with clouds, a house, a tree, a car and a person (all of which will be related to electrical charge), with plenty of time for the viewer to think about personal experience and connection to background knowledge. There are some concepts, such as charging by induction, that were introduced in a previous video, but the explanation is understandable without this information. Owens is also active on his YouTube channel, responding to questions from viewers. For example, he recently responded to a question about whether lightning comes from the ground or from the air:
“If I understand it correctly, it can go either from cloud to ground or from ground to cloud, and a typical bolt of lightning will involve several strokes back and forth. I don’t think it would meet in the middle, though. Also, however, it is my understanding that this is something that is not completely understood and is an area of active discussion and debate among scientists and meteorologists.”
On his YouTube channel, Owens has hundreds of videos on the physical sciences (ordered in relation to chapters of a book he used), as well as different topics in math. If you are a teacher who is feeling uncomfortable about teaching a new topic, this is a great place to get a friendly introduction to a basic explanation and examples you might use with a class.
I agree that this is a great resource for improving background knowledge in science. As an example of how good I think even just this one video is, I want to share some questions it stirred up in me. I think that is a sure sign of learning something – understanding enough to recognize holes in my knowledge and having some language to search for new knowledge.
–Keep in mind these are questions I didn’t even knew I had, nor would I have been able to voice them with much understanding. To folks who know the answers they might seem basic, or slightly off, but such is the nature of learning.–
In the video on lightning, he talks about clouds becoming polarized by the movement of air inside the cloud, where positive charge collects at the top of a cloud and electrons (negative charge) collect at the bottom. He goes on to explain how this effects the ground (particularly the way it drives electrons in the ground deeper, away from the clouds, leaving the surface (and everything on it) with a positive charge. And that eventually leads to a lightning bolt, as the electrons in the cloud jump to the positive charge on the ground. This goes along with our idea of a lightning bolt traveling from a cloud to the ground.
But at 6:22 in, he says lightning can travel from ground to cloud, but doesn’t say anything else about it. Using what I understand from the video, I understand at least one possibility of how that could happen. If a negative charge were to collect at the top of a cloud (instead of on the bottom) and a positive charge at the bottom, then the ground would have a negative charge (with the positive charge driven deeper into the ground). That could potentially lead to a lightning bolt going from the ground to the cloud… if it is always the electrons/negative charge that jumps.
Some questions I have:
– Is it always the electrons that jump or do protons also jump? Based on what I know about the structure of the atom, that would make sense, since protons are in the middle and it is the electrons the circle around the outside.
– Do protons ever jump? What would that look like?
– My idea of lightning bolts is that they usually travel from clouds to the surface. I can understand how the reverse might happen, but since my own experience of storms has lightning going top-down, I assume that is the far more frequent of the two occurrences. My first question – “Is that actually the case?” and my second is “Why?”
This is a great resource that leaves me knowing more than I did, but leaves me with questions and drives me to learn more. I look forward to watching “How Lightning Works, Part 2 and 3”.
I’m curious to hear what other videos folks watch and find interesting.
Mark, I found an infographic today that reminded me of this video and your response to it. You mention that the video raised some questions you have about lightning. Similarly, this infographic at Live Science, The Mysteries of Lightning, simply explains what we observe and know about lightning but also comments on what we don’t yet understand after 250 years of research.
Source: Life’s Little Mysteries
I really liked the video because it helped me to much improve my own understanding of lightning and I really like the infographic, because I think it might be something I can use in the classroom.
Eric, Thanks for posting this great video!
-Patricia
Patricia,
Thanks for sharing this infographic.The separation of charges in clouds came up as a question when I last taught a lesson on electrical charge. I was unable to answer the question, but just assumed I didn’t really understand the phenomena well enough. That’s certainly true, but it’s interesting to know that I’m not the only one. It’s surprising, isn’t it, since the polarization of the ground and discharge wouldn’t happen without polarization in the clouds? And we don’t understand why it happens in the clouds? (It makes me wonder a little bit if that’s true. I’m sure there are theories…)
Eric