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Science Buddies Blog: June 2011 Archives

A Student Puts a "T" on Turbidity

How's the water?


SODIS water disinfection uses PET bottles and the power of the sun over time. Image Source: SODIS Eawag, Wikipedia)

The answer depends on a number of variables, including where you are, especially if you are considering taking a drink. As Sarah Flaherty, a 9th grader at Westdale Secondary School in Hamilton, Ontario, discovered, purification strategies can be inexpensively enhanced by the strategic use of common materials. According to Sarah's science project, "Simplifying SODIS: Reduction of UV-impeding Turbidity through Macroscopic Filtration," an everyday T-shirt might offer a practical solution for eliminating excessive turbidity in water, a condition that can cause problems for solar water disinfection (SODIS).

In developing and rural areas, SODIS puts the power of the sun—and time—to work and offers an accessible and low-cost approach to improving the safety of local drinking water. The effectiveness of SODIS, however, decreases when the water is "cloudy"—or turbid.

Global Perspective

Taking inspiration from a family member who works for UNICEF, Sarah's project was an investigation seeking to improve SODIS-based water disinfection. Targeting the problem of turbidity, Sarah designed a filter that can be used to counteract the cloudiness of water. Her solution aimed to use readily available resources, like a T-shirt, and to create an enhancement that would increase effectiveness without significantly altering the cost of SODIS purification.

Sarah won a silver merit award at the 2011 Bay Area Science and Engineering Fair (BASEF), held this year in Hamilton, Ontario, and went on to participate in the 2011 Intel ISEF where she won Google's Secret Change Agent Special Award, an award that recognizes a project that has the potential to create positive impact in the student's neighborhood and/or on a global scale.

Making Connections

The quality of drinking water is directly related to the spread of disease. For example, outbreaks of cholera are often linked to contaminated water supply. According to the World Health Organization, 1.8 million people die each year from diarrhoeal diseases (including cholera), a statistic that the WHO estimates can be significantly reduced by water purification. Safer water and smart and affordable purification practices are key.

Students can investigate water purification in the following projects:

From the Field: Nora Volkow

Yesterday, the New York Times ran an in-depth profile of Nora Volkow, the neuroscientist in charge of the National Institute on Drug Abuse. In the accompanying video, Volkow talks about the psychology and physiology behind addiction.

According to Volkow, the impulse that drives one person to buy a chocolate bar from a bucket sitting at a checkout counter, even when she doesn't really want a chocolate bar, may be similar to the way an addict returns time and again to a substance, behavior, or activity even when he knows he shouldn't, really doesn't want to, or has vowed to steer clear. Good intentions aside, breaking patterns of addiction can be extremely difficult, and when it comes to substance addiction, the substance affects the dopamine levels in the brain—a high that addicts want to repeat.

Increased dopamine levels, alone, however, don't explain addiction. One time, in and of itself, doesn't create addiction. According to the New York Times article, researchers suggest that genetics play a role, as do changes in the brain that result from patterns of addiction.

Making Connections

If you are interested in human psychology, physiology, or neuroscience, you can use a bag of marshmallows, a bell, and a group of friends to explore similar issues of human behavior in the Enjoy It Now... Or Enjoy It Later? Understanding Delayed Gratification, project. Would you rather have one marshmallow now or two in 15 minutes? You might think you want two. But can you hold out? Don't like marshmallows? Substitute a favorite treat and put it to the test.

Building Bridges


Born on June 13, 1806: John Augustus Roebling, an engineer especially known for suspension-style bridges and the design of the Brooklyn Bridge. From straws to balsa wood to egg shells, students can get hands-on this summer exploring and testing bridge construction. In an episode of the "Magic School Bus," Ms. Frizzle's class experimented with gum drops and toothpicks. What will you use? (Image Source: Wikipedia)

Today in Science History: Are you following our updates on famous scientists and engineers? It's a great way to spark inquiry and discussion over the summer. We post these updates on our Facebook page. Please join us there!

A classic Magic School Bus episode involves making a bridge out of materials found in the bathroom in order to cross the bathtub, in which an alligator is lurking. To complicate matters, Ms. Frizzle's class has been shrunk! At two inches tall, the span of the bathtub seems about the size of the Grand Canyon!

Making Connections

Connected building blocks stacked vertically make a tower. But the same connected stack stretched side to side between two elevated objects creates a bridge.... and brings up bridge-related problems, like sagging! Shorten the distance of the bridge, and you may minimize the sagging. But if you need to span a bigger area, what can you do?

Tinkering with concepts of bridge design and principles of structural engineering is something students can explore alone or in teams, and summer is a great time to gather household supplies, and see what works. Bridge building offers a creative activity, a brain teaser, and an engineering project all wrapped up in one. Make it a challenge! Which kind of bridge is strongest? How can you test bridge strength? How can various kinds of bridges be reinforced to increase their strength? Which type of bridge holds up best in an earthquake? How wide can the bridge be before and remain strong?

In Action

For hands-on fun with bridges and an introduction to structural design, check out the following Science Buddies science fair project ideas:

Blow: From Marshmallows to Microbes

The parts of a woodwind instrument, like the clarinet reed and mouthpiece shown above, could turn the band into a bacterial hotspot! Photo: James Eaton-Lee Njan Wikipedia.

At Maker Faire a few weeks ago, I wandered with my kids through a maze of techno-geeky wonderment. We started our day-long exploration of things that lie at the intersection of science, art, and DIY with a roundup of scuttling, skittering, line-following, light-seeking bots. They might not be useful around the house, but there was plenty of simple robotics wow-factor to go around. Solar-powered, light- or color-sensing, motion-detecting... there were a bevy of bots to explore—and numerous opportunities to remind my young inventors, "See, you could program your Mindstorms® to do something like that."

Zigzagging around a corner, we ended up in front of the Howtoons booth. If you've poked around the Science Buddies directory of Project Ideas, you might have run into the Do Submarines Need Fins? project from the Aerodynamics & Hydrodynamics area. The project is based on Howtoons' illustrated Soda Bottle Sub engineering project. I am a big fan of the graphic novel format (yep, adults read them, too), and it's great to see the quality (and quantity!) comic-style work HowToons is doing illustrating science projects.

As we stood there looking at the samples on their table, the guy behind the table took a split-second look at my 7-year-old and pulled out a shiny white beauty of a PVC-pipe-based marshmallow shooter.

screenshot from Howtoons
Image: Howtoons

The marshmallow shooter is a classic HowToons illustrated design project, and he was quick to show off the admirable distance he could launch a marshmallow into the crowd (a belated "oops" to the lady in blue fifty yards or so away!). My little guy, saucer-eyed at the thought of beaning tons of unsuspecting people with squishy white pellets, and a veteran in the marshmallow shooter world, was quick to ask, "Can I try it?"

He couldn't try it, of course, because to use a marshmallow shooter, you have to put your mouth to one open end of the tubing and blow, the air making a rapid circuit through the pipes to propel the marshmallow out the other open end. Right... it was covered in mouth germs and filled with droplets of spit. Bottom line: marshmallow shooters should not be shared.

The HowToons guy explained that. (Maker Faire folks get plenty of practice explaining things to a curious but sometimes unknowing or young crowd!) I reinforced the germ-laded explanation. And we moved along.

With or without the chance to blow marshmallows, there was plenty to see! And the chance to push buttons and send gigantic fireballs shooting out of the top of a variety of devices once outside was enough to divert even a seven-year-old.

Making Connections

A few days after Maker Faire, I spotted a story at ScienceNews that brought the marshmallow shooter moment to mind: "Don't share that clarinet: Bacteria can linger on woodwind instruments for days." Hinging on recent findings from a team of microbiologists at Tufts University School of Medicine in Boston, the story notes that microbes linger longer on certain types of instruments than others. In particular, instruments that use a reed (a type of cane) harbor bacteria longer than instruments made of metal.

Another recent report in Science Daily also cites the lasting power of bacteria on instruments, both woodwind and brass. A study of 13 instruments that hadn't been played in at least a week turned up a whopping 422 kinds of bacteria.

While similar, the two reports seem to differ in terms of the "importance" of knowing that the band can be a microbial hotspot, and the findings do not conclusively indicate that sharing a woodwind contributes to the spread of germs between players. Even so, I'm figuring that sharing marshmallow shooters might be a safer bet!

Making it Your Own

Whether you're in the band or just want to know your risk factor with PVC piping, exploring the lifespan of microbes on instruments — or other blow-based apparatuses — is something that could be worthy of a DIY science project. Our Microbiology Techniques & Tips can help as you think about designing your own experimental procedure.

  • Curious about the difference between the lifespan of bacteria on reed-based instruments compared to metal ones? It may have something to do with the oligodynamic effect. You can learn more about the toxic effect of certain metals on bacteria in the Is the Gold in My Jewelry Real? project.
  • Got a novel idea for helping quickly, easily, and reliably disinfect instruments? Take a look at the Engineering Design Guide and get started developing and testing your solution! (See here for a list of standard approaches to cleaning instruments.)
  • Wondering if you can build a bot or program your LEGO® Mindstorms to use marshmallows? Get building with the Go, Gadget, Go! Building Robots with LEGO┬« Mindstorms┬« project. How far can your bot throw?

We want to see what you come up with!

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