Program 32: Polymers…diapers and goo?!?

I love revisiting certain programs from the early days of G3…and this program on polymers was begging to be revisited. Not only are polymers just the coolest thing in the world, but it’s also been a while since we had fun with some mess and goo :)

Polymers can be found just about everywhere – in places you might not even have realized. They are in natural materials like wool and silk (among many others), and then also in many man-made synthetic materials like nylon and rubber. [A rubber duckie, for example, is made of synthetic polymers.] Even the double-helix strand of DNA is a form of a polymer known as a “biopolymer.”  But what exactly is a polymer?

The word polymer means “many parts.” The individual parts that actually combine to form a polymer chain are called monomers.  Sometimes a substance can actually help polymer chains link together and form a more solid substance. The youtube video below, uploaded by TTScienceClub, does a great job of graphically showing the basic formation of polymers and linked polymer chains:

Our G3 scientists had the opportunity to test out polymers with two fun experiments:  “Diaper Magic” and “Goo!”

Experiment #1:  Diaper Magic

Materials:

  • Diapers (we used Seventh Generation size 3 diapers)
  • Dark colored construction paper
  • Scissors
  • Gallon-sized zip-top plastic bags
  • Clear plastic cups (I gave each scientist 2)
  • Plastic spoons for stirring

I love this experiment so much. For some reason, even just discussing diapers completely grosses out all of our G3 scientists – and they certainly don’t want to touch them. I think too many of our scientists are used to helping their parents change younger siblings out of dirty diapers, so it’s hard to imagine diapers from a scientist’s perspective :)

We’ve all seen diaper commercials on TV, where one brand after another claims to be the “most absorbent.”  But what makes a diaper so absorbent in the first place? Is it the cotton stuffing? Not really. It’s one of many uses of modern polymers. Tiny polymers no larger than a grain of sand are mixed into the cotton lining the inside of a diaper. Modern diapers actually contain a super absorbent polymers no larger than grains of sand – they are called polyacrylic acid and are designed to attract water molecules. Each polymer can absorb about 30 times it’s weight in water! All said, most modern diapers can absorb about a half cup of water.

Well, our G3 scientists got a chance to test this out!  Steve Spangler’s web site provides a great description of this experiment, along with the following how-to video:

Each scientist received their own diaper. We cut into the lining, pulled apart the cotton, and shook the polymer grains onto a piece of colored construction paper (to make it easier to see the white polymers). To make sure we got as many polymers as possible, we also pulled the cotton lining from the diapers, sealed it in gallon sized plastic bags, and shook it for a few minutes. [You'll be surprised at how many more polymers you can get by doing this additional step!] We poured the polymers into a clear plastic cup, and then added water 1/4 cup water. I also put water bottles on the tables so our scientists could add additional water in small increments to see how much water their polymers could actually absorb.  The result?  The polymers absorbed the water, and congealed to form a squishy, gel-like substance. If the gel-like substance is powdery and loose, it can still absorb water; if the substance is moist, you’ve already reached the capacity of the polymers you collected. Our scientists all pushed their polymers to the limit and ended up with a substance that was definitely more moist and liquid than it started out as.

I believe that if you leave the cup full of squishy polymers on a counter top for a few days (or longer) and allow the water to evaporate, the polymers should return to their original state…what do you think?

Experiment #2:  Goo!

Materials:

  • 1/4 cup glue (we used white, but clear glue should work as well)
  • 1/4 cup water (we used tap water)
  • 1/4 cup liquid starch (you can find this in most supermarkets, but you can also order liquid starch online from sites like Amazon.com)
  • Paper bowls (ideally lined so they can handle wet items)
  • Plastic spoons for stirring
  • Food coloring optional (we chose NOT to use food coloring)

Our second experiment involves every scientist’s favorite concoction:  GOO!  There are many different goo (or slime) experiments available online. We based our goo on a formula provided by Science Bob that is equal parts water, liquid starch, and glue. We specifically used 1/4 cup of each item in our mix. Though we didn’t do this the day of our program, food coloring can be added during the early stages to make goo of a specific color. First we stirred together the water and glue in a small bowl. You know the glue and water are combined well when it looks like you have a thick, milky liquid in your bowl. We then slowly added the liquid starch. The starch is the key goo ingredient; it is the substance that binds together (links) the polymer chains present in the glue and gives us our slimy goo. The more you stir the three ingredients together, they better they combine. Our G3 scientists loved the goo, especially since it is solid enough to pick up in your hands, stretch, and pound.

Below is a peek at our scientists in action. G3 is now on break until the first week of May, but I can’t wait until we meet again :)

Categories: Polymers | Tags: , , , | Leave a comment

Reminder: This week tracks A & B are combined!

madscientistHi, G3 scientists!

Just a reminder that because I was out sick last week for the Track A program, I am inviting all Track A kids to come to the Track B program this Thursday on April 3rd. Trust me – it’s going to be tons of fun – so I hope I see everyone there!

:) Nicole

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Program 31: Light & Color

I’ve always loved rainbows. There’s nothing more special than seeing a brilliant rainbow in the sky after a summer storm, or seeing dozens of miniature rainbows floating about your room thanks to a strategically placed prism in the window. But how do we see certain colors in the world around us? And is there a difference between the colors we see in, say, ink on paper, and the colors of light we might see in the sky via a rainbow?

I turned to “the master,” Bill Nye, to start off our Light and Color program to teach some key facts to our G3 scientists. Why does Bill Nye remain such a popular scientist with both kids and adults? He’s truly the master of honing a science topic down to a handful of key facts and concepts and presenting that information in such a fun and silly way.  We have a full line of Bill Nye DVDs at the library for anyone to check and take home, including his episode on Light and Color :)

From Bill, we learned (or were reminded of) several key facts about light and color:

  1. When we see a color in the world, we are observing the color that a specific object is reflecting. For example, we see a red apple as red because the apple is absorbing every single color except red. Red light is reflected, and thus that is the color we see for the apple.  For another example, if you are wearing a green t-shirt, you and everyone around you see it as a green shirt because it absorbs every color except green; green is reflected, and thus that is the color we see.
  2. White is all colors reflected; black is all colors absorbed.
  3. Black absorbs all colors and converts that light to energy or heat. This is why wearing a black shirt on a sunny day makes you much hotter than if you wear a white shirt. Or why sitting in black car in the sun is much hotter than sitting in a white car.
  4. colorwheelColored light behaves differently than colored pigments and dyes.  Most of us have heard the phrase “yellow and blue make green” before, right? And that’s true, at least for dyes/pigments. If you had yellow and blue paint, they would indeed mix together to make green paint. But what about yellow and blue light? For light, the primary colors are red, blue, and green. So, no colors combine to create green. But green and red light will combine to make yellow light. Or red and blue light will combine to make magenta light. Check out the color wheel to the right to see what some possible colored light combinations are.

OUR EXPERIMENTS

Experiment #1:  Chromatography

Chromatography is a term used to describe the separation of mixtures, usually with the help of a fluid.  As we know, black is the combination of all colors. So does that mean that black markers are the combination of all color dyes? Just a couple of colors?

Materials

  • Round filter paper or coffee filters  (we used 11 cm. filter papers; some experiments even use something as simple as paper towels)
  • A variety of black markers, including water soluble (washable) ones
  • Small plastic cups
  • Pipe cleaners, cut to size (for us, about 4-5 inches in length)
  • Some water (we used distilled, though tap water would work fine)
  • Table cloths (I mention them specifically because as you use water to separate the dyes in markers, you get the equivalent of water with food dye which can stain clothing, carpets, etc.)

A chromatography experiment can be done simply without some of these steps, but we’re scientists after all! We used Steve Spangler’s spin art experiment as the inspiration for our chromatography experiment. First we poked a hole in the center of the filter paper with our pipe cleaner, and then set the pipe cleaner aside. I instructed our scientists to put large, filled-in dots of black ink around the filter paper. You will see the best results if you put 4 or 5 large dots around the filter paper versus lots of tiny pin-point dots.  Next we dipped our pipe cleaners in the cups of water, making sure we pinched any excess water from the pipe cleaners. The final step was to put the pipe cleaner back through the center hole in the filter paper, and put one end of the pipe cleaner back into the water (like a flower stem going into water). The filter paper can simply rest on the top lip of the cup. You should notice water slowing moving from the center of the filter paper outward. Water is actually moving up the pipe cleaner stem thanks to friction, and is then flowing through the fibers of the filter paper in the same manner.

This process was actually a bit too slow for some of our scientists, so in most cases we pulled the filter papers off of the pipe cleaners, placed them on the table, and used the pipe cleaners to slowly drip water on the filter paper directly. Most of us only saw a partial separation of colors in the black dyes – namely, blue, some purple, and even some hints of yellow/orange. I also gave all of the scientists the opportunity to experiment with water soluble markers of other colors. We may not have had complete success in separating the black dye from the markers, but our scientists got to take home some pretty cool art!

Experiment #2:  Kaleidoscopes

Technically, this was more of a project than an experiment. I finally discovered a super simple way for our scientists to create kaleidoscopes of their very own…thanks to really nifty objects called rainbow peepholes.

Rainbow Peepholes

Rainbow Peepholes

Materials

  • Rainbow peepholes (you can buy these from various locations – I got mine from Amazon.com)
  • Recycled paper towel tubes
  • Duct tape or electrical tape (we used duct tape since I can get it cheap at the dollar store)
  • Scissors
  • Craft paper punches (optional – I bought a few at Michael’s in the scrap-booking aisle)

Steve Spangler was again our inspiration for this project. And the project is simple enough thanks to the peepholes, which are designed to naturally refract light. In fact, you can hold a peephole alone up to the light and you’ll see refracted light (in rainbows) through the peephole without the aid of a constructed kaleidoscope. To construct the kaleidoscope, you hold the rainbow peephole in place over the hole of one end of the paper towel tube, and then secure it in place with some tape….and you’re essentially done! You can cover the rest of the cardboard tube with tape to make it cosmetically more appealing if you’d like. Also, if you punch shapes out of circles of paper, hold them at the opposite end of the kaleidoscope, and then look through the peephole, you’ll actually see swirls of refracted color in the shape you punched. For example, I purchased punches for a star, puppy paw print, butterfly, and flower. If you punch a star out of a circle of paper, you’ll see star shapes in the kaleidoscope. According to the Steve Spangler site, you can also line the cardboard tube with tin foil for a dramatic result. We didn’t get a chance to do that, but you can give that a try at home and tell me what happens!

Experiment #3:  Colored Light

Materials

  • Flashlights (I got as many as I could at the dollar store so our scientists could work in small groups)
  • Sheets of colored cellophane (I got 8 1/2 x 11 sheets from Amazon.com)
  • Rubber bands
Red and blue light create magenta light.

Red and blue light create magenta light.

Red and green light create yellow light.

Red and green light create yellow light.

This experiment was inspired by something I read on HowStuffWorks about making colors. We didn’t have a ton of time to do this experiment (I was a little ambitious with my time), but our scientists got to at least try it out so that they can then attempt this one at home. Refer back to the color wheel for light at the top of this post. Our three base/main colors were red, blue, and green.  Grab 1 flashlight and place 2-3 layers of red cellophane over the top, held in place with a rubber band. Do the same with 2 more flashlights, but using green and blue cellophane. In some cases, I needed to play around with the lights to figure out how many layers of cellophane worked best. [I created multiple layers simply by folding the cellophane sheets.]

This experiment works best in a dark room (we closed the shades and shut off the lights in our program room). To create yellow light, take the flashlights with red and green cellophane. We found it worked best when we walked very closely to the wall so the light from each “colored” flashlight was very concentrated. Then you slowly move the two concentrated pools of light closer together on the wall. As they start to cross, you will see the new color of light emerge!

Below is an Animoto video highlighting some of the work of our G3 scientists with this program. See you next time for some fun with polymers!

 

Categories: Color, Light | Leave a comment

Program 30: Magnets

Finally!  I’ve been wanting to do a program about magnetism with my scientists for quite a while and I finally found just the right experiment for us.  But more on that later. First, let’s talk a little about magnets…

SAFETY RULES FOR MAGNETS

hqdefaultYes indeed, there need to be some precautions when handling magnets. They can damage many devices in the modern world. Even the smallest magnets can do permanent damage to:

  • Credit cards or bank cards (damaging the magnetic stripe on the back of the cards)
  • Audio Cassette Tapes
  • Older TV screens (LCD and plasma screens are not affected)
  • Older computer monitors
  • Video Cassette Tapes

Some of the world’s strongest magnets – neodymium magnets – are so strong that if your hand get between a 6″ neodymium magnet and the object it is attracted to, your hand would likely be crushed!

“THE IRON DETECTOR” & HOW IT WORKS

Interestingly enough, magnets are only attracted to iron…which also makes them the perfect “iron detectors.” If you hold a magnet up against other metals – steel, copper, etc. – you’ll see that there is no attraction.

Here’s a fun experiment for home, if you can obtain a smaller neodymium magnet. One of the main components of meteors from outer space is iron. And even though it is rare to see a large meteor hit the surface of the earth, we are constantly being showered with tiny pebble-sized (and smaller) pieces of meteors as they break up in the earth’s atmosphere. On his web site (with an accompanying video), Steve Spangler shows how you can detect and collect actual pieces of meteors from your own back yard!

Magnets are also made of two “poles” – referred to as the “North Pole” and the “South Pole.” Opposite poles are attracted to each other, and like poles repel each other. Thus, two North Poles will repel each other, but the North Pole of one magnet and the South Pole of another magnet will be drawn to each other.  Have you ever wondered how a compass works? Well, part of a compass is always attracted to the magnetic pull of earth’s North Pole, and the other side of the arrow is always attracted to the magnetic pull of earth’s South Pole. You can even use a simple magnet to help with directions. Our scientists tied a string to a ring magnet (round magnet with an open center). If you let the magnet hang in the air from the end of the string, the magnet’s own North Pole will eventually face North directionally because it is being attracted to the earth’s North Pole!

8130horseshoe_magnetAs a group, we also talked about permanent magnets and temporary magnets. A permanent magnet – like the one pictured to the left, can actually make an iron-based object temporarily magnetic. For example, if you place a nail on a horseshoe magnet, and pull the nail away, you can then use the nail to pick up small iron-based objects (like paperclips).

THE WORLD’S LARGEST MAGNETS

What’s the biggest magnet in the world? The earth itself!  In the video below, we learn a little more about how magnets work – and about the earth as a giant magnet:

As a group we also talked a bit about neodymium magnets and how strong the pull of some magnets can be. In the video below, we get a peek at the world’s largest magnet, currently housed in the world renowned “MagLab” in Tallahassee, Florida:

ELECTROMAGNETS

Electromagnets were a key focus for us given that our experiment of the day was also creating our own electromagnet using some simple-to-find items. Electromagnets are magnets that become active with the presence of electricity. Once the electricity stops or is interrupted, the object ceases to function like a magnet.

OUR EXPERIMENT

We used information and instructions from Science Bob as the foundation of our electromagnet experiment.

Materials:

  • 1 D-sized battery (other sizes can be used, but the experiment burns through the battery quickly so a larger battery will last longer)
  • 1 large nail with flat head
  • 1 36-inch long piece of copper insulated “bell wire” with the insulation stripped from both ends (it’s important that the wire is both insulated and copper…I bought my wire at a local Home Depot; it came as a red and white insulated piece wrapped together, but I simply unwrapped the two pieces so they could used individually)
  • Paperclips (to test the electromagnet strength with)

The steps of the experiment are simple enough. Leaving about a 6-inch lead, you wrap the wire around the nail (being careful not to overlap the wire loops on the nail). Our scientists were each able to fit about 35-40 wire loops on their nails.  When the wrapping was finished, there was a 6-inch length leading from both the top and the bottom of the nail.  We then used duct tape to solidly tape the exposed copper end of one wire lead to the positive end of the D battery (the end with the bump).  We then placed a square piece of tape on the other wire lead.  Once the second lead is connected to the negative end of the battery, the electromagnet is fully functional and the exposed tip of your nail becomes the magnet (though it may take a few seconds to get fully charged). You will notice both the battery and the nail getting warm to the touch. It’s best if you loosely tape the 2nd lead to the negative side of the battery so that it is easy for you to pull it away from the battery and turn off the electromagnet (to preserve the charge in the battery as long as possible between tests).

One Step Further:  How can you make the electromagnet stronger?

TIP – the key to the electromagnet’s strength is NOT the battery – it’s the wire! Try wrapping a second wire on top of the first wire around the nail, and connect both exposed ends to each end of your battery…

With the electromagnet active, our scientists tested the strength of their magnets by seeing how many large paperclips they could lift with the nail tip. Many of our scientists lifted 5 or more paperclips!  We then moved to a table I set up with various objects so our scientists could test both their electromagnets and other permanent magnets on various objects to see which objects magnets were attracted to. Everyone had a lot of fun exploring just how magnets worked with a variety of objects. Check out the video below for some highlights from our program. See you in March for our next programs!

Categories: Magnetism | Tags: , , , , | Leave a comment

Program 29: Balloon Bananza!

I felt it was time for our G3 scientists to once again have some fun with balloons. Not only are balloons a pile of fun, but they help us learn a lot about science! In fact, in just this one program our G3 scientists learned a little about:

  1. The Properties of Polymers
  2. Centripetal Force
  3. Friction
  4. Newton’s 3rd Law of Motion

We started the program with a quick discussion about the properties of polymers. In particular, how the rubber in balloons is made of long strands of molecules called polymers. And it is the elastic quality of the polymers that allows the balloon rubber to stretch. Our conversation then turned to centripetal force and friction. The word “centripetal” is actually Latin for “center seeking.” And that truly describes this force. Without centripetal force, objects would not be able to travel in a circular path (they would only be able to travel in a straight path). One example is how a satellite orbits the earth. In this case, the centripetal force is supplied by earth’s gravity (think of it like an invisible thread that links the earth to the satellite and keeps the satellite moving around the earth in a circular orbit). Another example is the swings ride at an amusement park, where the centripetal force is supplied by the chains that link the chairs to the central pole. I shared my favorite video with the groups. In the following video, Jeff Williams on the International Space Station (ISS), shows that, due to centripetal force, the bubbles in his iced tea package move to the center of the package and form a large, singular air bubble when the package is put into a circular path.

EXPERIMENT #1:  The Balloon Skewer, or what I call, “Balloon on a Stick”

Materials:

  • Clear balloons are a must (a bought a package of 70+ at a party store)
  • Wooden skewers (the longer the better – again I found some at a party store, but I suspect some grocery stores have them as well)
  • Some liquid vegetable oil in a cup

This is definitely an experiment designed to impress a crowded room :) Thanks to my favorite scientist Steve Spangler, I impressed our scientists with a demonstration from his web site called The Balloon Skewer. By coating a standard bamboo skewer with vegetable oil (for lubricant), you can push the skewer in one side of the balloon and out the other side…without popping it!  [The trick is making sure the entry/exit points are where the balloon's rubber is LEAST stressed, or more opaque looking then the rest of the balloon - near the base where you tied off the balloon, and at the opposite end and top point of the balloon.]  Each G3 scientist was given a clear balloon and a skewer to try their hands at this demonstration. An important early step is inflate the balloon as large as you dare, and then release 1/3-1/2 of the air before you tie off the balloon. This actually helps stretch out the polymers and gives you a better chance at success when you aim to slip the wooden skewer between the polymer chains and through the balloon itself. The vast majority of our scientists were a success…though the sounds of popping balloons could be heard here and there throughout the room.  Practice makes perfect!

Experiment #2:  The Spinning Penny

Materials:

  • Clear balloons are a must
  • One penny per person

With our next experiment, we had a chance to see centripetal motion at its best. The Spinning Penny is an experiment described on the Steve Spangler’s web site. The experiment itself is very simple. A single penny is placed inside a clear balloon. The balloon is inflated and tied off with the penny still inside.  After shaking the penny a bit, the balloon is then swirled to help start the penny on a circular path inside the balloon itself. Due to the limited amount of friction, the penny can stay on its circular path for close to 30 seconds before gravity begins to slow it’s path! Our scientists all managed to create this very cool demonstration of centripetal force. [Special Note:  It is important that the balloon is pointing toward the floor as well as your eyes when you inflate it - there is a danger of a choking hazard if you choose to tip the balloon above our head to inflate with the penny inside!]

Experiment #3:  The Screaming Balloon

Materials:

  • Clear balloons are a must
  • One zinc hex nut per person (though any size works fine, we used a 1/4 inch diameter nut)

This experiment is actually a fun variation to The Spinning Penny. For The Screaming Balloon, we replaced the penny with a zinc hex nut…and guess what? The nut also moves on a circular path within the balloon due to the centripetal force we supply, but there is more friction between the hex nut and the balloon thanks to the the shape of the nut, and thus we get a high-pitched whining sound! Very fun for us…maybe not so fun for friends and family :)

Experiment #4:  Balloon Rockets

Materials:

  • Any balloons will do (we made sure everyone used the same size balloon for fairness since we did some mini races)
  • String
  • Straws (if you have the bendy kind, you can just cut off the bendy portion)
  • Tape (any kind will do, though masking tape proved a little easier to work with)
  • Chairs

What better way to see Newton’s 3rd Law of Motion in action than some friendly competition with balloon rockets! According to Sir Isaac Newton and his 3rd Law of Motion,

For every action, there is an equal and opposite reaction

To test this principle, we followed the guidelines of Science Bob to create our very own balloon rockets. We divided our group of scientists into 2 teams, and each team assembled a rocket “track” – a pair of chairs with some kite string strung between them (like a zip line). A straw was threaded onto each string. Each scientist received a colored balloon (clear is not necessary for this experiment), and was instructed to inflate the balloon as large as they wanted without tying it off. While pinching the open end of the balloon closed, the balloon is held under the straw and taped to it (with the mouth of the balloon pointing in the opposite direction that you want the balloon to travel in). When you’re ready to the see the balloon in action, you just unpinch the mouth of the balloon and let go! The result mimics the take-off of a rocket, with the air pushing back in one direction and propelling the balloon in the opposite direction. We had some friendly competition to see which team’s balloon would travel the farthest. Every scientists received a small prize for their efforts :)

At the end of our hour, every scientist was able to bring a copy of these simple demonstrations and experiments home with them.  Below is a nifty video showing our scientists’ efforts during all of the balloon experiments. Until next time!…

Categories: Forces, Motion, Polymers | Tags: , , , , , , , | Leave a comment

Program 28: Banana DNA

For our final program of 2013, I wanted us to dig deep into science. That’s right – I broke out the test tubes and magnifying glasses and even some pipettes! This month we revisited one of my favorite programs from the past: Banana DNA. Our G3 scientists learned how to extract actual DNA from bananas!

dnaAs always, the program kicked off with a brief discussion. We talked about the nature of DNA itself. Do humans have anything in common with a rhinoceros? Or a frog? Or even a tree?  The answer to all questions was YES. All life forms contain DNA, which determines what that life will look like and more. In the case of our bananas, the DNA is what tells the banana to be a certain color, or a certain shape, or a certain flavor. We watched some great videos from Dole about what goes into harvesting and shipping all of their bananas. [Video 1: Dole Banana Development & Care; Video 2: Dole Harvesting Bananas.]  I also pointed out a sheet of fun banana facts that each scientist could take home with them.

Cavendish Banana...soon to be extinct?

Cavendish Banana…soon to be extinct?

One very interesting thing we discussed is the fact that most Americans eat only one type of banana: the Cavendish. And due to a fungus that is attacking Cavendish banana plants around the world, in 5 or 10 years the Cavendish banana could very well become extinct! When that happens, we will all be forced to begin eating a completely different kind of banana. Our G3 scientists’ children or grandchildren may never know what a Cavendish banana tastes like! Though this isn’t the first time a banana species has become extinct. Prior to 1950, most Americans would have been eating a banana called the “Gros Michel,” but a fungus made that banana species extinct before any of our young scientists (and maybe even their parents) were born!

OUR EXPERIMENT

Using the instructions from the magazine Scientific American as a guide, the G3 scientists discovered that we can extract the actual DNA from bananas using a few household items like dish soap, salt, rubbing alcohol…and of course bananas! I made a few tiny modifications based on experience that I’ll note below.

Our supplies for the day:

  • 1 ripe banana per scientist
  • 1/2 cup of distilled water
  • 1 resealable zip-top bag
  • 1 tsp. salt
  • 1/2 tsp. liquid dish washing soap (any kind)
  • Isopropyl alcohol (rubbing alcohol) (chilled in the freezer)
  • 1 coffee filter
  • 1 narrow and clear glass or test tube
  • 1 narrow wooden coffee stirrer

The first step was mashing up the bananas…something that we all enjoyed :) Each scientist was given a whole banana sealed in a zip-top plastic bag. The goal was to achieve a “pudding” consistency. Both tracks did a great job of firmly, but gently, breaking apart all of their banana lumps and creating a bag of banana mush.

In a separate cup, we combined 1 tsp. salt and 1/2 cup of distilled water, stirring until the salt was dissolved. This salt water was then added to our banana “slurry,” gently kneading to combine the ingredients in the bag. We then added 1/2 tsp. of liquid dish soap to the “slurry,” again gently kneading to combine the ingredients.  This led us to our trickiest step:  straining our banana slurry (to collect just the banana liquid in a cup). [The soap actually helps to dissolve the membranes of the cell walls that hold the DNA, and the salt helps to draw the DNA strands toward each other.]

Photo Dec 05, 4 46 48 PMI made some modifications to our previous work with banana DNA (and to the steps as identified by sites like Scientific American) to help with our success. Each scientist placed a coffee filter in a clear plastic cup, holding it in place with a rubber band. [This was an important and successful improvement to the process! In the past, so many of our filters fell back into the cup forcing the slurry to be restrained time and again.] Once we had maybe 1/4-1/2 inch of banana liquid in the bottom of our cups, each scientist carefully worked with a partner to remove the filter and remaining slurry from the top of the cup so that all that remained was the strained liquid beneath. Using pipettes, the G3 scientists then filled their test tubes about 1/2 way up with the banana liquid. They then used a clean pipette to add chilled isopropyl alcohol to the top of the test tube. [NOTE:  You can keep the alcohol in the freezer...it will stay in liquid form!]

The online experiment descriptions say you may have to wait up to 8 minutes to see some results, but almost all of our G3 scientists had immediate and successful results in hand. All G3 scientists were able to extract the white, fibrous, web-like DNA from their bananas! We tried out best to preserve the DNA bits in plastic baggies for those scientists that wanted a souvenir, but I think that photographs are the best way to preserve the results of this experiment. Check out the nifty slide show below of our scientists (from both tracks) in action:

In a final note, many of the banana facts I shared were obtained from the Chiquita banana web site.

I’m looking forward to seeing everyone in 2014 when our next programs will start. Happy holidays!

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Program 27: Pasta Towers

It’s never a bad idea to revisit a fun program in a new way, and that’s just what we did with Engineering. When the G3 scientists last addressed that topic, our project was designing bridges using only cardboard sheets and string. This time, our scientists were challenged to build pasta towers using nothing but marshmallows!

As always, we started our program with a brief slide presentation to talk about the concept of Structural Engineering. What is a structural engineer? Well, according to Dictionary.com structural engineering is defined as:

—…a field of engineering dealing with the analysis and design of structures that support or resist loads.


Structural engineers can design everything from city skyscrapers to bridges to roller coasters! We looked at pictures of some of these structures to see what shapes could be found in the structure designs – shapes that could help our scientists in designing their own pasta towers. The most commonly used shape – the one that consistently provides some of the best support for a structure – is the triangle. As an example, take a look at the images below and see if you can spot all of the triangles used in the structure designs.
structures


I also shared a few fun videos with everyone. One of the videos we watched showed the Tacoma Narrows Bridge collapse of 1940. Another showed the largest house of cards I’ve ever seen being triumphantly destroyed by its builder. The one below was definitely a favorite during the programs – showing a giant domino tower from construction to demolition to clean-up :)


THE ENGINEERING CHALLENGE
Our G3 scientists were challenged to building the tallest tower possible using only:
  • 75 strands of uncooked spaghetti (regular, not thin)
  • Mini-marshmallows for the joints (as many as needed)

They also had to be able to balance a large marshmallow from the top of their structure. There was scrap paper and pens available for anyone who wanted to sketch a design before construction began. There were also rulers available at each table for anyone who wanted to precisely measure pieces of pasta for their structures. Most scientists dove directly into construction and tested and revised designs as their construction progressed. And few to none used the ruler to measure pasta pieces as they broke them up for their construction – there was a lot of on-the-fly tailoring of pasta lengths. Thus, we had a lot of varied, highly creative structures that emerged in both program tracks. The tallest tower was created in Track A at 36+ inches!

All scientists were given cardboard sheets to transport their creations safely home. [Note: The pasta structures actually become stronger over time. As the moisture evaporates from the marshmallows, the marshmallow joints dry and become more solid (like cement!).] Check out the sample slide show of project images below created in Animoto.

See you in December for the next G3 meetings!

Categories: Engineering, Structures | Tags: , , | Leave a comment

Happy Halloween!!

Happy Halloween to all of my favorite budding scientists!

Here’s a little fun video from my favorite Muppet scientists, Dr. Bunsen Honeydew and his trusted assistant Beaker…enjoy!!

Categories: Just For Fun | Tags: , , , | Leave a comment

Program 27: Parachutes Redux

parachute_forcesI felt it was about time for our G3 scientists to revisit one of our earliest programs, so in October both of our classes tackled parachutes and the forces that maneuver them. I started our programs with a short discussion about what a force is. For example, a push force could be something like one person pushing another person backwards. An example of a pull force could be gravity itself, and how gravity pulls objects downward toward the earth’s surface. Forces have the ability to change the speed or even the direction of an object. We also talked about the forces at work when someone is using a parachute. When somebody jumps out of a plane and parachutes to the ground, two key push and pull forces are in action. Gravity rapidly pulls the person toward the ground. Then the parachute helps to provide a crucial push force that slows a person’s descent and keeps them from smacking into the ground. How is this push force created? Air collects under the parachute and provides resistance, or drag, that essentially pushes back against the “pull” of gravity and makes a person fall at a much slower and safer rate to the ground.

A year ago, I had shared a video with our group showing Joseph Kittinger’s world record free-fall parachute jump from an unprecendented height. In 1960, not only did he become the first man in space, but as of last year he held the world record for the longest free-fall parachute jump! Wearing a special pressurized suit, he rapidly climbed skyward in a helium balloon – so high that he broke through the troposphere and could look back on the earth from the darkness of space. And then, he did the unthinkable – he jumped!  However, as of 2012, Felix Baumgartner (using similar methods to Kittinger) became the new world record holder, finally breaking Kittinger’s longstanding record. In fact, he broke three world records! He now holds world records for…

  1. The highest manned balloon flight (at over 128,000 feet)
  2. The highest freefall distance (of about 120,000 feet)
  3. The record for being the first free-falling human to break the sound barrier (his top speed was around 833 miles/hour, and the speed of sound is around 761 miles/hour).

Kittinger actually still holds the world record for the longest freefall duration at 5 minutes and 35 seconds (Baumgartner did a free-fall for 4 minutes and 20 seconds). Though it should be no surprise that Baumgartner was unable to break this record since he also fell at a quicker rate than Kittinger. Below is a highlight video of Baumgartner’s jump.

OUR EXPERIMENT

To test both push and pull forces, the task of the day for our G3 scientists was to create and release their very own parachutes! An example of a simple parachute design can be found on the website for PBS’s program FETCH (though there are many similar experiment instructions to be found online). Our materials for the parachutes were simple enough:

  • 10″ x 10″ squares cut from plastic garbage bags
  • 10″ x 10″ squares cut from tissue paper
  • 9″ x 9″ squares cut from cloth
  • paperclips (our “human beings”)
  • String
  • tape

Photo Oct 17, 4 53 39 PMThe real challenge was figuring out which material made for the best parachute (in other words, the slowest drop to the ground). Each G3 scientist was instructed to first do a test launch of a parachute using a single square of each type of material. In this way, they could get a sense for which material might make for the best parachute. Once each of the 3 materials were tested, the scientists were given the freedom to design their own parachutes by combining materials, using additional paperclip weights, etc. Our scientists launched their parachutes by climbing a tall ladder (always under the watchful eye of fellow librarian, Kelley). I timed all launches with my handy stop watch, and all scientists had pieces of paper to record their various times on.

Early in our testing, it became obvious that the cloth squares were too heavy and fell pretty quickly to the ground. However, both the garbage bag squares and the tissue paper squares provided some excellent “hang time” in the air. Our best parachutes from each class (the longest time in the air) were both constructed of multiple garbage squares taped together. In both cases, we had good air time solidly over 4 seconds! Below is a video montage of many of our parachute runs from both class days. I hope everyone had as much fun testing their parachutes as I had watching the test runs!

I’m looking forward to seeing everybody again in November when we pick up with the next session of G3 programs :)

Categories: Forces | Tags: , , , , , , , , , , , | Leave a comment

Program 26: The Science of Bubbles

Photo Sep 26, 4 50 36 PMIt doesn’t matter what age we are…blowing bubbles is always endlessly entertaining. And while it’s fun to just drift through an afternoon blowing bubbles in a zen-like state of calm, in G3 we are scientists…so it’s only fitting that we explore “bubble-ology” in a little more detail. Let’s look at the science of bubbles…

As a framework for the day’s activities, I showed this wonderful youtube video from ‘Carmelo the Science Fellow’ to our scientists. While his jokes may be corny at times, Carmelo does an excellent job talking about the science of bubbles while providing experimenters with some important tips for creating the strongest, most creative bubbles. What kind of science can be seen using bubbles? Well, first of all, bubbles can be a compelling way to prove that gases have mass. It’s easy to see that a desk or a chair (solids) have mass and take up space. But how can you show that air and other gases take up space? As you blow into a wand to create a bubble, the skin of the bubble expands and becomes a visual indicator of the increased area that the gas or air is taking up in space. Carmelo also had some great advice about creating bubbles, summarized by two clever catch phrases:

Bubbles love things that are wet, and they won’t be upset.

If a bubble touches something dry, the bubble will go ‘bye bye.’

As our G3 scientists discovered, by wetting a surface (like a paper plate), it was much easier to create large, long-standing bubbles. And a wet surface also helped to facilitate some pretty cool bubble tricks, like blowing a bubble within a bubble. You can even stab your bubble with a wand or a straw safely, as long as it’s wet! [That's how you're able to blow a bubble within a bubble :)]

OUR EXPERIMENTS

For our experiments, the first step was for me to create a handful of tubs filled with a bubble solution for our use. I used several 33.9 oz. empty coffee canisters to hold the solution – they were deep enough to allow for some fun experimentation and also had a handy lid that I could just put on top to preserve the solution. I also used the following recipe (though tripled) from the experimentals web site:

  • 3 cups of water
  • 1/4 liquid detergent (must be dishwashing detergent – not body soap or laundry detergent; I used a store brand)
  • 2 tbs. pure glycerin (I found a small $5 bottle at CVS; Stop & Shop also sells it)
  • A pipette (or straw)
A pippette

A pipette

Though the glycerin is noted as being an optional ingredient in most recipes I found, I believe it is actually an important component and one that will make your homemade bubble solution as close to a store bought bottle as possible. The glycerine actually acts as a stabilizer, preventing the bubbles from breaking and evaporating as quickly as they would without it. You get much stronger, longer-lasting bubbles with the glycerin added in. We also used modified pipettes for creating our bubbles. We snipped off the tip of the widest portion of the pipette, and that became the end we dipped into the bubble solution, blowing in through the smaller, narrower end. However, any drinking straw would also work just fine for creating the bubbles.

I let our scientists spend a significant portion of the program experimenting with creating bubbles. Many wanted to create the single largest bubble possible; others wanted to see how many bubbles they could pile one on top of another. Most of our G3 crew found success in blowing a bubble within a bubble, and many just had fun with blowing bubbles at each other or creating cooperative bubble experiments with a neighbor. I did, of course, want to challenge our scientists, so I tested their skills and asked them all to create a square bubble.

Square bubble success!

Square bubble success!

squarebubble

Square bubble?! That’s right. With the right tools, a scientist can do almost anything. Using pipe cleaners and drinking straws, I gave the G3 crew instructions on how to create a 3-D cube. The pipe cleaners were cut into 4 inch lengths, and the straws were cut into 2.5 inch lengths. You need 12 pieces of each to complete the cube. Some instructions for this cube device use only pipe cleaners in the construction, but I found the design on Steve Spangler’s web site the best – it creates the most stable cube. [Full instructions for the cube assembly can be found by following my link to Steve Spangler's web site.] Many of our scientists struggled in assembling the cubes, mostly due to soapy fingers and distractions from the sheer joy of blowing bubbles. However, we definitely had some square bubble success in both classes. How is the square bubble formed? Basically, when you completely submerge the cube into the bubble solution and then pull it out, bubble solution is stretched across each of the cube’s walls. Once you dip your pipette into the bubble solution, insert it into the center of the cube and then a blow a bubble in the center of the cube, the bubble you created pulls the walls of the cube to itself. Thus, the cube framework actually forces your malleable bubble into a square shape!  [FURTHER TESTING:  Build a 3-D triangle frame using pipe cleaners and straw pieces...do you think you could then create a triangle-shaped bubble?...]

Below is a collection of short videos showing just how much fun our scientists had with the science of bubbles. This science is definitely easy and safe enough to keep exploring from home!…

 

Categories: Bubbles, Properties of Matter | Tags: , , | Leave a comment

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