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Science Buddies Blog: October 2011 Archives

Candy Chromatography


Brightly colored candies in your Halloween bag might be the key to your next science investigation! Image: Wikipedia.

Trick or treat! Today's the day! But what will you do with all the candy you accumulate going door to door in this year's costume? Can you really eat that much candy? After the initial excitement of dumping your bag of sweet loot in the floor, sorting it out, exclaiming over favorites, maybe making some sibling trades, and eating a few more than usual pieces of candy for the day, what will you do with all of it?

You might just find that your next science project is lurking there at the bottom of your bag!

Candy Appeal

Beyond the sugar, part of the fun of a candy is how it looks. It may taste great, but the success of a candy also depends on features like shape, color, and size. Food developers really have to think about the appearance of the candy. Will it catch your attention? If it does, you might choose it over another candy, which is what candy marketers want.

Many candies have brightly colored shells or coatings. Even if they all taste the same, a handful of a single kind of candy might contain a number of different colored exteriors. Those bright colors are made up of various dyes. Your favorite candies may melt in your mouth and not in your hand, but with a bit of science, you can figure out what dyes were used for each color.

Chromatography is a technique used to separate a mixture or solution into its individual components. So instead of seeing just the end result (the sum of all components), you can backtrack to find out what ingredients were used to make up the final solution—the color, in this case.

In the Candy Chromatography: What Makes Those Colors? food science project, you can experiment with paper chromatography to investigate the colorful exteriors of favorite candies. Once you have a bit of practice analyzing colors of a single brand of candy, try comparing two favorite coated candies. Are the reds the same?

Vampire Bats and a Bat Detector


Only a small percentage of bats are blood-drinking vampire bats, like the one shown here, but all bats in the sub-order Microchiroptera use echolocation to help them navigate and locate prey. Image: Wikipedia, Ltshears.

By Kim Mullin

Predators in the Night

What's that whooshing and swooping through the night? What gets its nutrition from bird and mammal blood? What species' animal kingdom name means "hand-wing"? Vampire bats, of course! The idea of blood-thirsty bats may sound like something straight from a movie or Halloween story, but vampire bats are real. While most of the thousand different bat species are harmless, there are three bat species that live on animal blood, all native to Latin America.

Drinking Dinner

You might think that vampire bats have a terrible set of teeth, but they actually have fewer teeth than other types of bats because they drink their meals. Vampire bats make a small cut in an animal's skin and then lap up the blood with their tongue. A special feature of vampire bat saliva keeps the blood liquid so that they can drink for up to half an hour! Otherwise, the cut in the animal's skin would soon coagulate, or start to scab over, just like when you get a small cut on your own body. How can they drink for so long without the prey noticing? They are so light that the animal they drink from continues sleeping through the whole process!

They can drink for a long time, but the amount of blood a vampire bat slurps up isn't enough to hurt its victim. The bigger risk stems from the fact that some vampire bats carry rabies that they can pass on through their bites.

Beyond the Vampires

The blood-drinking habits of vampire bats give "bats" a creepy reputation, but most bats are completely harmless. Bat species live on every continent except Antarctica. Some are voracious insect eaters, vacuuming up hundreds in one night. That's a great benefit to humans and the crops that we eat. Most other bats eat fruit or flower nectar. Just like birds, bees, and butterflies, bats do a great job of pollinating plants and of spreading seeds so new plants can grow.

Bats in the Backyard

Do you have bats in your neighborhood? Maybe you've heard the whoosh of their wings in the night. But with the right tool, you can listen in on the ultrasonic signals they produce to locate objects in their environment. In the Bat Detector: Listen to the Secret Sounds of Bats mammalian biology science project, you can use a bat detector to help you learn more about bat communication. The bat detector is a useful and fun tool for studying the biology of this nocturnal flying mammal.

Glow-in-the-dark Chemistry


Glow-in-the-dark items can be fun year-round, but the eerie glow of a chemiluminescent reaction like the one shown here fits right in at Halloween! Image: Wikipedia.

It wouldn't be Halloween in many houses without an assortment of light-up sticks. My kids call them "glow sticks," and though they don't last all that long, they're always fun for trick-or-treating. Really, they're fun throughout the year. Many bedtime hours are interrupted by the discovery of a forgotten canister of glow sticks, all of which simply have to be activated right then. (Why is one at a time never enough? Mom logic says that the canister could last an entire week rather than just a few minutes of snapping and a few hours of glowing. Kid logic says differently!)

When I was growing up (back in the nineteen hundreds, as my kids like to remind me), glow sticks were more a safety feature. You kept light-up sticks on hand in the house for emergencies or power outages. I remember them being thicker, brighter, typically neon green, and not intended as a toy. But, getting to break out and break up a light-up stick was always a treat—even if it meant the electricity was out!

Today, glow sticks are everywhere. Circuses. Ball games. Concerts. Amusement parks. Today's sticks appear in many colors and are thinner and less expensive. No longer are these sticks destined to be tucked away for a cool-Mom-rainy day or a true blackout. They're good for anytime. Did I mention they're thinner? And cheaper?

Tale of a Stick Gone Bad

A stash of glow sticks turned up in my house recently, which meant some bedtime procrastination, all in the name of 'glow' fun. As the tube of sticks was divvied up and activated, one of them broke during the bend-and-crack phase. The snapping of the sticks, of course, is one of the cool things about glow sticks. The sensation of breaking the inner core, breaking it again, and again, and again until the core is completely liquefied is undeniably fun.

We didn't realize the outer plastic casing had broken on one until the lights were turned off, and we realized a set of hands were dotted with a few specks of 'glow.' With the lights back on, we tried to see where the 'glow' had come from. My young detective waved the stick all over the place and shook it hard, trying to reveal the break. While the leak wasn't large, it was there. When we turned the lights off again, the rug showed a star-studded smattering of glow dots from the shaking. Bending the stick a bit more, we finally saw where the liquid was escaping, and we "drew" on a paper towel with it for a bit, the neon liquid the ink on our white paper towel—a glowing signature.

Even a broken glow stick can be fun.

But they don't last all that long.

And, really, they aren't all that bright.

Turn those statements into questions, apply a bit of electronics know-how, and you're all set for a cool and illuminating science project!

Measuring 'Glow'

The Measure Luminescence in Glow-in-the-Dark Objects chemistry Project Idea lets you put the 'glow' in glow sticks to the test. Just how bright are they? For how long? And does it make a difference if you crack them open in hot weather or in cold?

In this science project, you can find out!

What's Going On In There?

At the heart of a glow stick is a chemical reaction that starts when you twist or bend the stick. A reaction between two of the chemicals in the stick releases enough energy to "excite" the electrons in the fluorescent dye causing a fluctuation in energy levels and the release of light—the chemiluminescence and the "ahhhh" moment in the dark.

In this project, you are guided through the assembly of a light detector, a circuit that lets you measure the light produced by these sticks. The sticks themselves will be closed up in a jar. You might miss seeing the 'glow,' but you'll get a lot of satisfaction tracking the readout on the light sensor—and knowing you built the circuit yourself!

Still... make sure you stock up on some extra glow-sticks, just for fun! And, once you're done with the experiment, you can re-use the jar from the project (without the foil covering), cut open a bunch of cracked and glowing sticks, dump the contents together in the jar, and enjoy an unusual "night light" for a few hours!

Biodiversity at Halloween: A Spider Variety Show


Kim and her kids spotted an Argiope aurantia like the one shown here on a daily walk. Image: Wikipedia, Deisy Mendoza.

Family Exploration

Remember, your students are curious about the natural world around them. A simple walk to school or through a park can be a revelation—and a great opportunity to talk about science. But you have to slow down and look! There are spiders—and much more—to be discovered!

Related posts:

By Kim Mullin

There are about 34,000 different species of spiders in the world, and in Northern Virginia we see quite a lot of them in the fall when they are busy eating and reproducing in preparation for the coming winter. While a large spider in the house can make me jump, I like to think that spiders are benevolent creatures, eating the insects that pester us. And, their webs are a perfect addition to the landscape at Halloween!

On our walk to school each day, my children and I pass a neighbor's garden. In the growing season, it's brimming over with flowers and vegetables, and we enjoy seeing what's new. One day, however, we spied something different and unexpected—an enormous yellow and brown striped spider! We'd never seen such a large spider outside of a display case. Its markings were very distinctive, so we easily identified it at a spider website later that day. It was a black and yellow argiope, or corn spider. It turns out that this spider is harmless to humans, but it sure was doing its part to control the insect population!

After successfully identifying one spider, we took a closer look at the other spiders in our neighborhood. We discovered that light brown funnel weavers are common in our yard. They create an open-ended funnel to one side of their web and hide there until something becomes entrapped! We also discovered a wolf spider, which hunts for its prey, rather than making a web. A hunting spider was a new idea for me!

Biodiversity—Learning About the Creatures Around You

What kind of spiders do you have where you live? Or other creatures? If you are curious to learn about your local biodiversity, explore these Science Buddies Project Ideas:

  • Bug Vacuums: Sucking Up Biodiversity: Have you ever wondered what a wildlife biologist does? These scientists study and monitor the health of habitats and ecosystems, often by identifying and counting plants and animals. Take on the role of a wildlife biologist by examining the biodiversity of insects in your own backyard using a homemade bug vacuum!

  • Finding Phyla: Animals come in all shapes and sizes, each a small part of the amazing diversity of life. These differences can also help us to classify animals into different groups. Which group do you belong to? How many different types of animals can you find around your home? Do this experiment to investigate the diversity of animal life around your home.

(Science Buddies Project Ideas in Zoology are sponsored by the Medtronic Foundation.)

Sounds Like Halloween

Family "Listening" Fun

What does Halloween sound like? Ask your kids, and they'll probably come up with a rapid list of eerie sounds they associate with Halloween. You can explore principles of the Movie Music science project with students of all ages. If you want to separate the music from the movie, you might gather instrumental music samples that each have a different "feeling" (e.g., happy, scary, hopeful). Listening to these kinds of tracks and categorizing them by sound can help all of you "tune in" to what you're hearing! Need some "scary" scores? Get your glow sticks ready, huddle under the blankets, and sample a few from the list at left. (Note: It may be best to do this during daylight hours with younger students! You can also try the same listening experiment with other, non-scary types of music.)

From public haunted houses to dark and spooky neighborhood garages opened up for a ghoulish Halloween walkthrough, a big part of the "scare" factor involves your ears. What you hear may be as important in creating a scary experience as what might jump out at you or tickle your neck. Indeed, part of what makes a haunted house perfectly eerie is the soundtrack that goes along with it—all the noises orchestrated to raise the hair on your arms, make you shiver, and leave you with little doubt that there are things unknown lurking around you.

The same is true at the movies! The music that goes along with high and low points in a movie differs based on the genre or kind of movie and on the emotion or context of the scene. Put the music from the opening of an animated film in place of the music for an intense moment in a thriller, and the effect of the scene might be totally different.

Put It to the Test

Whether you are gathering sounds for your own haunted walkthrough or hoping to keep the season alive after the jack-o-lanterns have all been tossed, the Movie Music project can turn a fascination with eerie sounds into a science exploration—one that could carry you right into the next season! What goes into the composition of a perfect thriller soundtrack? Is there a formula? What instruments are common to music used with different kinds of scenes or movies? What key? What tempo? Do the scales rise or fall?

Gather some samples from various genres of movies, and see what you can find out about the importance of the backtrack in the success of various types of films. When you tune in and really "listen" to what you are seeing on the screen, you might be surprised at how important the music is!

The following list contains links to a number of creepy, classical and movie tracks to help get you started thinking about the similarities of "scary" music, the kind of music you might hear in a suspense or mystery movie:

Happy listening!

Trick-or-Treat Science


Image: Wikimedia Commons.

Halloween is next week, and you may have your mind on the treats you hope to rack up going door to door in your neighborhood, candy bag open. While Halloween's entourage of ghouls, goblins, and zombies may push science from your mind, you don't have to carve too many pumpkins to turn up a treat bag's worth of great science ideas related to Halloween.

All this week we'll be spotlighting some creepy crawlies, some things that go bump in (or light up) the night, and some other Halloween fun—all with a jolt of science thrown in.

Stay tuned for a round-up of Halloween science ideas—especially projects you can get started on after you've calmed down from the haunted house, after you've counted out and sorted your candy, and once the sugar buzz drops and the reality of a science project on the horizon comes back into focus!

The Science of Too Sour


Tang, an orange-flavored, powered drink developed by William Mitchell was popularized on board NASA's Mercury flight in 1962. Experimenting with powdered drinks and levels of "sour" can offer kitchen science fun for the whole family! Image: Wikimedia Commons.

Born on October 21, 1911: William A. Mitchell, a food scientist who created many classics for General Foods that might ring a bell for teachers and parents, from Pop Rocks candy to Tang. Even Cool Whip and quick-set Jell-O, a duo often used together, lead back to Mitchell.

You may or may not stock Mitchell's foods in your fridge and cabinets, but his list of food-related patents leaves little doubt that he was an innovator with an eye to the ways in which chemistry is at the heart of food science. Showing students the connection between cooking and science can be eye-opening, fun, and creative—plus, it's a great way to spend time together and to make them more independent in the kitchen even as you whet their appetite and curiosity about science.

Mouth-Puckering Fun!

One of the great things about science experiments related to food is that kitchen science can be immediately hands-on. Everyone can get involved mixing and baking and tinkering with recipes and ingredients—and then everyone can help taste-test! There are many food-related Project Ideas on the Science Buddies website that are perfect for families wanting to do a kitchen-based science activity. You could bake cookies or boil pasta together, but for many kids, "sour" may be an exciting place to start with food science!

Do your kids have a penchant for all things sour? Do you? Is a tolerance or a love of "sour" something that differs from person to person, similar to tolerance for saltiness or sweetness?

My kids might run a mile from peppermint. They might hide behind the couch at the thought of cinnamon (no Atomic Fireballs here!). But they love anything sour, and today's drugstore candy shelves never fail to offer up the goods. A current favorite (though Mom- and dentist-disapproved) is a lollipop that also has a sour liquid you squeeze directly on your tongue. It's the kind of makes-you-wiggle-all-over super sour they love. But is it something only a kid would love?

It's a question worth asking, and the Do You Have the Willpower to Taste Something Sour? project gives you a way to put the question to the test in your own kitchen. This project, geared toward early grades, is great for a classroom experiment, or families can modify the project (using fewer volunteers) to make it a fun activity for a hot afternoon, a playdate, or an engaging over-the-weekend experiment. As you and your students mix up batches of lemonade with varying levels of "sour," you'll all have fun—and learn something about human biology and food science!

(Science Buddies Project Ideas in Health and Human Biology are sponsored by the Medtronic Foundation. To view other parent- and family-focused science resources and content, visit our Parent Resources section.)

An Engineering Manager Behind a Heart-monitoring Site

Jeff Hagen / Science Career profile

Jeff originally considered a career in electrical engineering but followed his interests into computer science. Today, he's an Engineering Manager at Medtronic and works to help oversee testing on CareLink, a heart monitoring site.

Meet Jeff Hagen, an Engineering Manager at Medtronic for the last nine years.

Jeff Hagen leads a team of software verification test engineers who deploy specific web-based applications that medical personnel use to provide patient care. Jeff and his team work on a computer-based diagnostic tool called CareLink. The Medtronic CareLink® Network is a web-based application and remote monitoring service that gives clinicians, doctors, and nurses online access to data transmitted from a patient's implanted heart device. The reports and data available from CareLink can be comparable to an in-office visit, and medical practitioners using CareLink rely on the data from CareLink to be accurate and available when needed—24/7.

Jeff and his small team of testers and software engineers work to make sure that's the case!

From Electrical to Virtual Circuits

Jeff started out with plans to follow in his father's footsteps as an electrical engineer. Once he realized that he enjoyed computers more than circuits, he changed his major to computer science, a field of study that capitalizes on two of his primary interests: math and computers. "Computer science is an engineering discipline that blends the mathematics and logic of engineering with the technology of computers," explains Jeff. "It's the best of both worlds." Today, with more than twenty years of experience in the field of software engineering, Jeff knows the career path he followed was the right one for him. "I do not look back on my decision to go into computers and leave electrical circuits behind. Computers and I have always understood each other."

Keeping Up to Date

Jeff knows that a big challenge he and his team face is keeping pace with the rapid growth in technology. Ongoing research and developments means that technology changes frequently, as do the languages, equipment, and approaches that make various technologies "work." Staying ahead of the curve and keeping up to date with changes and advancements in one's field is always important, but when your work involves the well-being of patients, there may be a correlation between staying "current" and ensuring the best patient care possible.

According to Jeff, he and his team monitor and evaluate their systems throughout the year, but they have to be cautious before adopting upgrades and new approaches. With a product like CareLink, Jeff and his team can't assume that newer is always better. "We are under much scrutiny to ensure our patients' safety, and as a result, we are not often the first to try out a new technology," he explains. Before adopting new approaches or making changes, Jeff has to be certain that patient safety won't be compromised.

In some areas of software testing, a "bug" is a small error that creates a problem in the application. A "bug" in a game or a word processing program, for example, might be an inconvenience or cause a user frustration—or maybe data loss. But in software engineering related to patient health care, there can't be any bugs. There is no room margin for error when a patient's heart is at stake, which is why teams like Jeff's are so important.

As a former programmer, Jeff says his understanding of computer science is an advantage in working with software verification and testing. "Having a computer science degree teaches your brain to be a better problem solver and think of issues in terms of cause and effect," says Jeff. "Finding and fixing software bugs is a very important part of what we do. If we make a mistake the patient could be impacted!"

Flexible Thinking

Day to day, Jeff needs to keep the "big picture" of his team's core application in mind even as they troubleshoot and test specific issues. Being able to employ stages of the engineering method is a critical component of his job. "As an engineer, I would say that being fluent in the practical real-world engineering method is of vital importance," says Jeff. It boils down to "being able to define and analyze a problem, specify the requirements, choose the best solution available, and implement [that solution] quickly and with strong quality."

Helping People

While careers in computer science and software engineering can mean long hours at a computer—and little time "in the field," Jeff never forgets that the product he oversees and helps maintain is one that is used to treat patients. It's a connection that makes working on CareLink and for Medtronic especially rewarding for Jeff. Jeff works in a cubicle among a hundred cubicles on the eighth floor of a modern office complex in Minnesota. He works long hours with his software developers and test engineers both in the U.S. and in Europe. He's far from the "hospital scene," but every few months, Jeff gets the chance to meet patients whose lives have been transformed by products and services offered by Medtronic. "This is the BEST part of working at Medtronic," says Jeff. "Realizing that what you do actually saves and prolongs life!"

When asked if he ever thinks about what it would be like to work on a very different kind of technology—like video games or a popular online destination like a sporting site—Jeff admits that those kinds of projects might be fun, but he questions, "If you work on your "hobby", does it remain fun as your hobby, or does it become just a job?"

For Jeff, knowing that he's helping better people's live by doing something he loves makes his career the right one for him. "It would be very difficult to get a better feeling than that from any job," says Jeff.

Biomedical Engineering and Heart Health

Katie Hilpisch / Career Profile

As a biomedical engineer at Medtronic, Katie Hilpisch is making a difference in people's lives. "It is rewarding to meet someone who finds out that you work at Medtronic and wants to tell you that someone they know has a Medtronic device."

For Katie Hilpisch, a senior biomedical engineer at Medtronic, helping devise therapies for heart patients is all in a day's work!

According to Katie, biomedical engineering offers an exciting combination of research, problem-solving, and fieldwork. Biomedical engineering brings engineering, medicine, and biology together, but not all biomedical engineers do the same things or work on the same kinds of product development, research, and testing. At a large company like Medtronic, there may be many biomedical engineers working on different facets of a larger health issue. Katie and her team, for example, work in the area of "heart health," exploring medical therapies for patients with heart problems, specifically electrical stimulation (pacing) therapies. At the same time, other biomedical engineers work on different aspects of heart health, like exploring new imaging technologies that let doctors better see "inside" the body or researching the ways different substances interact in the human body.

A Collaboration Between Math and Science

Figuring out the right combinations and solutions to improve a heart patient's quality of life is a puzzle that biomedical engineers are constantly trying to solve. According to Katie, "my job is all about math and medicine!" It's a combination students might not immediately think about, but for biomedical engineers, science and math work together as keys to helping problem-solve, troubleshoot, and find solutions.

"Here's a very specific example," says Katie, "on a project I was recently working on, we were trying to reduce the flow of blood through an artery by 80%. We had to find the area of the vessel to determine an appropriate new size of the vessel to get an 80% reduction. Think geometry. Think statistics. Think measurements and calculations that you are learning right now in school!"

Between Desk and Lab

Katie splits her time at Medtronic between desk work and lab work. She estimates she spends 75 percent of her time doing computer-based research and analysis and 25 percent of her time working in research labs or in hospitals.

"Data analysis is a huge part of my job," she explains, "so using software to analyze data and calculate statistics is a big part of my repertoire. " Reading and staying up to date with both current and historical research and trials is also critical, says Katie. You have to "read anything that gives you insight into what has already been done or what other people are working on," she explains, "We don't want to re-invent the wheel."

In fact, Katie wants to take what exists and find new and better wheels. It's a process of finding the right combination and approach to improve life for patients, and that's what she enjoys most about her job. "Hands down, I most enjoy helping patients. It is very rewarding to come to work every day and get the chance to do something that helps people who are sick."

Advancing Treatment

Working at a global company like Medtronic, means that specialized groups are able to take advantage of each other's research and development when envisioning new solutions, therapies, and treatments. Katie's group isn't working on drug therapies, for example, but others at Medtronic are. Similarly, Medtronic biomedical engineers work with drug pumps, pacemakers, and other equipment that may come into play in a plan for a new heart therapy.

The process of putting new therapies into action, however, is one that takes time. New therapies go through many different types of testing, including lab-based testing using computer simulations or machines built to test possible answers. According to Katie, other stages in testing may include pre-clinical testing at Medtronic's Physiologic Research Lab, small patient studies to test for safety and effectiveness, and finally larger patient studies.


Curious About Biotechnology and Medicine?
Learn more in our new Medical Biotechnology interest area!
The outcomes of large-group studies help biomedical engineers evaluate whether or not the therapy is better than not having the therapy.

Answers Take Time

On paper, the point from A to B may seem pretty clear-cut, but it can take years of testing to ensure a therapy is safe and effective. With testing of new therapies averaging 3-5 years, it is clear that accepting that testing takes time is part of the game plan for biomedical engineers. "Usually when we are planning for products, we are looking at things in a 1-2, 2-5, 5-10 and 10+ years' time frame!"

A Future in Biomedical Engineering

According to Katie, students interested in a possible career in biomedical engineering should take as much math and science as they can. But beyond schoolwork, Katie encourages students to also think outside of school. "Figure out what sets you apart," she urges. "Do something nerdy outside of school. Join a group that takes apart toasters and puts them back together. Or even volunteer at a local science museum. " For Katie, when you think about what you want to do with your life, the mantra is simple: "Always do something you love. Then it won't be 'work.'"

For Katie, heart health and biomedical engineering is where she wants to be right now. "It is rewarding to meet someone who finds out that you work at Medtronic and wants to tell you that someone they know has a Medtronic device," says Katie. "My own grandfather has a Medtronic pacemaker, so when people ask what gets me to work every day, I tell them, in the end, it's the patients."

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