Voici un retour sur la dernière semaine de #GeomorphologyLessonDaily. Nous élaborons ces leçons en pensant aux lycéens, mais leur contenu peut également être utilisé pour d’autres niveaux.

Headcut in a straight channel

lundi

A headcut is an abrupt vertical drop in the streambed. As the streambed drops, the waterway may lose access to its floodplain. This can then exacerbate stream bank erosion.

Here is a good short illustration of headcutting, incision, and subsequent channel evolution.

Sediment is removed from the lower end of a straight reach causing one or more headcuts to travel upstream. The first headcut is emphasized with an arrow that fades as the headcut becomes indistinct. As the incision progresses the channel begins to meander and form bars/terraces and the channel evolves.

Use the pause control in this short clip to take your time looking at these forms.

What sorts of human activities do you think might cause headcutting?

#STEM #homelearning #remotelearning #onlinelearning

Landslides: why do they happen and what can we do about them?

Mardi

According to engineering geologist Dr. Anika Braun, there are several approahces we might take to reduce our risk to landslides.

“Whether a mountain slope is going to fail and form a landslide depends upon a combination of different ‘preparing’ and ‘triggering’ factors.”

Fantastic post by Dr. Anika Braun, lecturer in engineering geology at Technische Universität Berlin, on Geoscience For The Future.

What are some of the contributing factors to increases in landslides? What are some ways we can help mitigate landslides in the future?

Earth – An ebook from NASA

mercredi

A beautiful collection of satellite images that reveal our planet from perspectives we don’t often get to see.

The photos and text “tell a story of a 4.5-billion-year-old planet where there is always something new to see.”

#EarthDay #EarthDayFromHome #EarthDay2020 #EarthDay50

Mobilization of bed material

Jeudi

This short little video shows just how much energy is contained in a water flow, and how a very minor disruption can release that energy.

The camera is placed into shallow, high velocity flow in the Jacks Fork River in the Missouri Ozarks. The turbulence and changes in velocity distribution caused by the camera housing dislodge bed materials and cause them to move.

#STEM #earthweek #remotelearning

Science in our daily lives

Vendredi

How often do you think about fluid dynamics? The answer is likely, not often. It’s not really the kind of thing that’s relevant to your daily life, right? Think again!

“The film does a nice job of highlighting some of the many examples of fluid dynamics that we come across in our daily lives.” -@fyfluiddynamics https://fyfluiddynamics.com/…/today-im-sharing-one-of-my-f…/

#ScienceAtHome #STEM #physics