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Podcasts, webcasts, online video and audio on science and engineering topics.
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Podcasts, webcasts, online video and audio on science and engineering topics.

Clay Water Filters for Ghana

Posted on May 13, 2013  Comments (6)

Pure Home Water, Ghana manufactures and distributes AfriClay Filters in an effort to bring clean water to 1 million people. So far they have delivered filters to provide 100,000 people clean water.

The process is simple. Water is placed in a clay filter and gravity pulls the water through the pores left in the clay during firing.

Sediment and bacteria are filtered out in several ways:

  • Physical straining: the particles are too large to fit through the pores in the clay
  • Sedimentation or adsorption: particles come to rest on or stick to the clay
  • Inertia: friction in the pores keeps the particles from passing through

Bacteria are also killed by a coating of colloidal silver (a disinfectant), which we apply to all filters that pass our quality control tests. While sediment and bacteria are filtered out, the molecules of water are small enough to pass through the pores in the clay.

The filters are sold to those who will use them. The effort has shown a willingness to pay by villagers in remote Northern Ghana (those earning < US$1/day). I imagine (I am just guessing) the prices are subsidized; in the last decade more (most?) appropriate technology solutions will have those benefiting pay something for the benefits they receive. My nephews are working on a similar effort in India, using bio sand filters, I plan to post more on that later. There is current a campaign to help fund the delivery of water filters to Indian villages.

Related: Solar Powered Water Jug to Purify Drinking Water – Electric Wind – Student Invents Solar-Powered Fridge – Reducing Poverty

Make Crosswalks More Visible

Posted on December 25, 2012  Comments (2)

Good simple idea. And then executed well – for nighttime at least. Crosswalk lights up when in use giving drivers a more visible clue to stop.

Related: Ministry of Silly Walks – Kindergarten Students Pedel Their Own Bus to School – Passion for Mechanical Engineering Nurtured as a Child – Bird Feeder That Automatically Takes Photos When Birds Feed – Encouraging Curiosity in Kids

The Science Behind Hummingbird Flight

Posted on August 24, 2012  Comments (5)

Aerodynamics of the hovering hummingbird

Hummingbirds and insects have evolved for sustained hovering flight from vastly different ancestral directions, and their distinct phylogenies underlie the differences in their aerodynamic styles. In all other birds—and, presumably, hummingbird ancestors—the downstroke provides 100% of weight support during slow flight and hovering. Given that many birds possess the mass-specific power (using anaerobic metabolism) to hover for short periods, the selective pressure on hummingbird ancestors was probably for increased efficiency (resulting in stiff wings with greatly simplified
kinematics), and an upstroke muscle (the supracoracoideus) that makes the recovery stroke rapid, while contributing enough to the hovering power requirements to allow the downstroke muscle (the pectoralis) to operate within its aerobic limits.

In other words, this pseudosymmetrical wingbeat cycle is good enough, and although hummingbirds do not exhibit the elegant aerodynamic symmetry of insects, natural selection rewards ‘good enough’ as richly as it does our aesthetic ideals

Related: Praying Mantis Attacks Hummingbird – Friday Fun: Crow Sledding, Flying Back Up and Sledding Down Again – Bird Using Bait to Fish

Great Webcast Explaining the Digestive Systems

Posted on August 11, 2012  Comments (2)

You will learn things like why it is so important to chew your food well (increase the surface area for enzymes to get at the food). Our bodies also have adapted to provide a huge surface area for the digestive system to work; the small intestine alone has a surface area of 250 square meters (larger than the size of most apartments). Your small intestine is 4.5 to 10.5 meters long.

Related: Staphylococcal Food Poisoning – Energy Efficiency of Digestion – Tracking the Ecosystem Within Us – Waste from Gut Bacteria Helps Host Control Weight

Landing Curiosity on Mars

Posted on July 15, 2012  Comments (1)

Touchdown on Mars will take place August 5th, 2012 (PDT or August 6th EDT and GMT).

Related: NASA’s Mars Curiosity Rover – Mars Opportunity Rover Continues Extended Exploration – Sunset on Mars

Scientists Singing About Science

Posted on June 30, 2012  Comments (1)

Fun video with scientists singing about science.

More scientists singing science songs: Friday Fun, Large Hadron Rap – Cambrian Explosion Song – The Sun is a Miasma of Incandescent Plasma – Protein Synthesis: 1971 Video

Video of Young Richard Feynman Talking About Scientific Thinking

Posted on May 15, 2012  Comments (3)

The enjoyable video above shows a young Richard Feynman discussing how scientific thinking can advance our understanding of the world.

Related: Feynman “is a second Dirac, only this time human” – Science and the Excitement, the Mystery and the Awe of a Flower – Classic Feynman: All the Adventures of a Curious Character

Lean Science: Using Cheap Robots to Aid Research

Posted on March 21, 2012  Comments (4)

Fun video showing how scientists use Lego Mindstorm robots to aid research into creating artificial bones. Lego Mindstorm robots are useful at a very reasonable price.

The webcast also includes this practical quote from Michelle Oyen, lecturer in the Department of Engineering at Cambridge University: “without your bones you would be a pile of goo lying on the floor.”

The thinking discussed in the webcast echos the lean manufacturing principles discussed in the Curious Cat Management Improvement Blog: finding good solutions to aid people in doing their jobs. The type of custom solutions they discuss here are great.

This type of use of technology is great. One of the problems we often see with technology solutions though is when they are imposed on the workplace in a way that doesn’t aid people. There is a big difference between what Toyota does (using robots to make people’s jobs easier) and what others do in trying to copy Toyota (using robots to eliminate jobs). Lean manufacturing stressed the importance of using brainpower people bring to work every day. You want to use technology to enable people. These scientists understand that. Unfortunately many managers don’t.

Related: Lego Mindstorms Robots Solving: Sudoku and Rubik’s Cube – Open Source for LEGO Mindstorms – Rubick’s Cube Solving Lego Mindstorms Robot

Photosynthesis: Science Explained

Posted on March 20, 2012  Comments (2)

Another very good webcast on a science topic from Crash Course. It is packed with info, thankfully you can pause and rewind as much as you need. Well normally you can, YouTube decided to not let me do that just now 🙁

Related: Exploring Eukaryotic Cells – Science Summary: Photosynthesis – Ten Things Everyone Should Know About Science – Gamers Use Foldit to Solve Enzyme Configuration in 3 Weeks That Stumped Scientists for Over a Decade

Exploring Eukaryotic Cells

Posted on March 4, 2012  Comments (3)

This webcast is packed with information on the makeup and function of eukaryotic cells, which are the type of cells found in animals. It is part of a interesting series of science webcasts by Crash Course. The webcast style might be a bit too hyperactive and flippant for some but the content is quite interesting and the videos they are are of similar style and quality so if you like this one you can subscribe to their channel. They offer quite a few webcasts on science but they also offer webcasts on history.

Related: Plants, Unikonts, Excavates and SARs – How Cells Age – Midichloria mitochondrii

Webcast of a T-cell Killing a Cancerous Cell

Posted on February 9, 2012  Comments (1)

Very cool. Very good job by University of Cambridge to make this kind of material available openly online. I find this kind of video amazing. Every day you body has this going on all day long. How amazing.

This is what it looks like when cancer gets smacked down by a T cell

This was shot by University of Cambridge medical researcher Alex Ritter, and is 92 times faster than real time.
…
Cells of the immune system protect the body against pathogens. If cells in our bodies are infected by viruses, or become cancerous, then killer cells of the immune system identify and destroy the affected cells. Cytotoxic T cells are very precise and efficient killers. They are able to destroy infected or cancerous cells, without destroying healthy cells surrounding them.

Related: Using Bacteria to Carry Nanoparticles Into Cells – How Cells Age – Video showing malaria breaking into cell – Synthetic Biologists Design a Gene that Forces Cancer Cells to Commit Suicide