Video explorations of topics of interest to students of the Earth Sciences at the introductory college level. Produced by Katryn Wiese, Professor of Geology, Oceanography, and Paleontology at College of San Mateo (full-time) and City College of San Francisco (adjunct)
Liked & subscribed! Excellent presentation. Just what I need to see in order to understand local groundwater, a failed artesian well, but a pond that has remained full. Thanks!
Completely agree with Edward, excellently done and best overview I have seen! Could you extend this to discuss the southern California regions of San Diego to Los Angeles? Or even respond to this question in the comments?
Glad you enjoyed it! I will add your suggestion to my list for additional videos and upgrades. Some day when I get more time I'll start working through this list again. 😀
So, the city charges me for the water I use, watering my lawn even though that water eventually seeps back into their pumps that they again charge me for? Thank you for explaining this capitalist circle-jerk, for me.
One of the most amazing things is how the Sun came into being, and why it still exists, burning fuel at thousands of degrees per second in the vacuum of space, giving the world life!
Error analysis is VERY important! It's always my fear that in many news stories that the error in the published result is actually larger than the answer. Think how important this is when talking about temperature measurements and climate change! Always include the error with the number so people will understand the importance of the number given.
I really like information dense delivery. This one is fantastic. Kudos to Ms. Wiese. I've garnered many pieces of California geology over the years but this is a fantastic comprehensive delivery. Thank you so much.
Thank you for this... my professor did a horrible job explaining this in their video, so I'm glad I found this (and a warm hello to my students who found their way here, haha!)
The center of mass in the Earth-Moon system, also known as the barycenter, is located within Earth itself. It lies about 4,671 km (2,902 miles) from Earth's center, which is approximately 75% of Earth's radius on the moon side. While it seems like the Moon orbits Earth, both the Earth and Moon actually orbit this common center of mass. However, because the Earth is much more massive than the Moon, the barycenter is located closer to Earth's center, causing the Earth to wobble slightly as it orbits the barycenter. This means that the elliptical path we generally attribute to Earth's orbit around the Sun is actually the orbit of the barycenter of the Earth-Moon system. So you would observe the earth wobble about the barycenter the side opposite the moon is traveling faster around the barycenter and thus it is centrifugal force that is causing the bulge opposite the moon in about the same magnitude as the moon facing side.
The largest grains settle quickly in still waters isn't what you observe in nature. Big rocks are found on storm beaches and fast flows. Rocks, pebbles, gravel all the way down to mud are distributed along a gradient of turbulence or energy. This is a good presentation but it travels way to fast.
This was very well explained! Last week I was debating with a friend of mine that claimed that sun rays always hit perpendicularly in the Equator line. I argued that due to the tilt of Earth's axis with respect to the orbit around the sun, that didn't make sense. He quickly googled something to prove himself right, and read it to me while I was driving. So, I accepted it. But, it never quite made sense. Today, I decided to look for seasons' explanations, and came across this video. As it turns out, this video proved my argument. My conclusion from your video: The “parallel” where the sun rays hit perpendicularly moves periodically like a pendulum between -23.5 deg to +23.5 deg of latitude (a.k.a. between the tropics), with the middle point of the pendulum's trajectory being the 0 deg latitude -- a.k.a. the Equator line (“parallel”). This "pendulum" would have a period of T = 1 year.
Wouldn’t Pb still decay at the same rate, no matter the amount of weathering? That’s kind of the point of using a certain mineral as diagnostic testing, isn’t it? That they can reliably decay at a certain rate!?! Or do they use something else like chromite for weathering?
Yes, Pb would continue to decay at the same rate. However, once a mineral has experienced weathering, it is no longer a closed system. Parent and daughter could have been added or lost. Thus it is not possible to rely on the ration of Parent: Daughter to determine how much time has passed.
I don’t think this is very clear at all. The video does refer at one point to “the sun hitting the Earth at 90deg” and later “the North Pole is further away”. I don’t think it is ever clarified fully that it is not the distance from the Sun, but the angle of presentation that creates the seasons. The OU used to explain this by using a slide projector (I know, you have to be old enough - think of a data projector), where if you angled this from the side some of the image would go beyond the screen on to the wall. This loss of image on the screen directly relates to how much sunlight, and subsequently heat, is reduced.
Thank you for your feedback. You are correct that in this short video, I focus on the Earth tilting towards and away from the Sun. I highlight locations and times where the sun hits directly at 90° and where it is fully present or never present (Arctic and Antarctic circles). I do indicate that direct sunlight provides the most intense sun and heat, but I do not discuss how sun hitting at an angle less than 90° is more dispersed over a larger area on a spherical object (Earth) and thus provides less overall heat. It would be a good addition for a new version. I will add it to my list. Nonetheless, I do focus at the start on rebutting the idea that the Earth's distance from the Sun has any impact on the seasons. Perhaps because it comes at the start, it was less impactful for you, who were looking for it later on? Here is the script: docs.google.com/document/d/1GgnE_BJbENVlFSODx4M4HuNH5yv9fRlX7emCwvvIVD0/edit?usp=sharing **I will create a new version eventually, so I appreciate the feedback.
Thanks for rapid response and positive comments. I was indeed aware of the earlier rebuttal regarding distance being a factor, but I feared there may be a disconnect from later discussion for some viewers.
Earth Rocks gets an "A" for first rate teaching. The best mode of learning measurement at the K-12 level used to be shop classes. The disaster of the Gates Common Core Curriculum over the last 20 years has destroyed shop classes and other hands-on learning such as Home Economics. I witnessed years of students who did not master things as basic as a twelve-inch ruler. They had no concrete grasp of measurement because the curriculum became based on increasing levels of abstraction. This lack of basics has had dire consequences when these students show up in higher education.
Thank you for your feedback. 😀 Note: unfortunately sand wouldn’t show foliation. It’s equidimensional. To see foliation, you need an elongated mineral like actually actinolite or kyanite or hornblende. These have shapes similar to pens. Or flat planes like micas (and paper). Only these will align when put under pressure.
8 years ago in South Africa there was a boy getting ready to write his final examination in matric on Geography, he wasn't good at science and his marks where hanging on to dear life, and it all came down to geography. So he studied and studied and he came across this very same video, but he ignored it because what are the odds of this being asked in the paper, Question 5.2.1 what season is in the Southern hemisphere during September😂😂, long story short i passed my exams and guess what job i chose, a geography teacher. So every now and then when its time to teach about this very same topic, i just open youtube look for this very same video and let you work your magic. Works everytime
Because to a tsunami (from its perspective), the ocean seems like a shallow puddle. The wavelength of a tsunami is about 200 km. It thus feels bottom at 100 km depth. Anything shallower than 100 km is dragging on the tsunami wave energy and showing it down. The deepest part of the ocean is only 11 km.
