Monthly Archives: August 2015

Meet New Horizons: 7 Space Experiments

January 19, 2006. A piano-sized robot blasts upwards from Earth on a massive rocket and escapes the gravity of our home planet, bound for distant adventures. For a small community of scientists, launch day kicks off the long closing chapter of a story years in the making. To most of the world, it’s the beginning of the New Horizons saga. Nearly a decade of spaceflight later, the brave little probe has earned name recognition in households around the world. Its iconic images and data are the product of its payload. On board, seven cleverly designed experiments work together to gather new science and send it home.

Meet the mechanical and digital brains of New Horizons: Ralph, Alice, REX, LORRI, SWAP, PEPSSI, and the Student Dust Counter (SDC for short, designed and built by actual undergrads)!

Let’s start with their jobs. Together, the seven instruments tackle three primary goals:

  1. Study Pluto and Charon’s geology and morphology,
  2. Make maps of these two worlds, and
  3. Study Pluto’s atmosphere– particularly, how it’s escaping the dwarf planet.

That’s right, Pluto’s atmosphere is escaping! It’s blowing away in the solar wind, and at an astounding rate. It turns out that the dwarf planet and its dynamic atmosphere look almost like a giant comet.

PlutoComet

Source: http://pluto.jhuapl.edu/News-Center/News-Article.php?page=20150717-2

This phenomenon is Alice, SWAP, and PEPSSI’s territory. (REX also studies atmospheric science, but is busy figuring out what’s happening down low, near the surface.) Alice, a spectrometer, is in charge of detecting UV rays and figuring out how much of which gases are present in Pluto’s upper atmosphere. SWAP specializes in measuring the solar wind that’s blasting the dwarf planet’s “air” out into space. SWAP’s data, combined with PEPSSI’s analysis of the escaping atmosphere, define the size and shape of the lopsided nitrogen cloud around Pluto, shown as a blue shell in the image above.

Intriguing as the case of the runaway atmosphere may be, it’s not, of course, the biggest thing to come out of the Pluto flyby (which, by the way, occurred at 30,000 mph, over 17 times faster than the average bullet). New Horizons has filled a significant gap in the common consciousness by taking our best image of the former ninth planet from a tantalizing but blurry hint to a gorgeous, high-res map…one with a prominent familiar feature, no less! 

File Aug 31, 11 41 08 AM

Sources: http://news.nationalgeographic.com/2015/07/150714-pluto-flyby-new-horizons-space-planets/#, http://apod.nasa.gov/apod/image/1507/Pluto04_NewHorizons_1042.jpg

The exquisitely detailed world on the right is brought to you by LORRI. This telescopic camera gives us such a nice view of Pluto that we can see features as small as 100m across on its surface. LORRI’s partner in science, a spectrometer named Ralph, reads visible and invisible light emitted by Pluto and Charon. The readings tell scientists on Earth about the composition and climate of these distant worlds. We now know, for instance, that much of Pluto is wrapped in a shell of frozen methane and nitrogen!

Each of these experiments is making invaluable contributions to a new foundation of knowledge about the former ninth planet and its cosmic neighborhood. There’s something special, however, about the last instrument aboard New Horizons. It’s been designed and built by students! Young scientists are taking part in the exploration of space– and they’re returning important results.

SDC assembly

Assembly of the SDC detectors. Image credit: LASP/UC Boulder

The SDC is all about counting dust. That’s right, dust. Each time a particle hits one of its detectors, a small electric signal registers. Unglamorous as it may sound, space dust is key to understanding both the past and the future of planetary formation. The distribution of debris in our solar system– the way the particles have arranged themselves over the course of the sun’s life– can tell us a lot about how our world and its neighbors came to be. Our sun gives us a home-court advantage; it’s more difficult to study the history of distant planetary systems. Once we have a deeper understanding of our own corner of space, we’ll be better prepared to analyze similar information gathered from light-years away.

As of this writing, all seven experiments are just over 3 billion miles away and receding into the Kuiper Belt at tens of thousands of miles per hour. Next up: a demystifying flyby of another KBO (Kuiper Belt Object), to be chosen and targeted in 2016. We can’t wait to see what New Horizons sends home this time!

Liquid Nitrogen: Deep Freeze Science

It was a cold night in Russia’s Sakha Republic. Tiny Oymyakon, widely regarded today as the coldest town on Earth, was used to going about its business in near-arctic temperatures. On February 6, 1933, its residents braved the lowest temperature ever measured in an inhabited location: ninety degrees below zero, Fahrenheit.*

LNstairsArcticCold

The coldest place on Earth

Source: http://www.nasa.gov/sites/default/files/coldestplacerecords.png?itok=nAYJEo7W

In the most brutal corners of our planet, far from human settlement, the freeze is more intense. High on a ridge on the East Antarctic Plateau, in shadowy pockets explored only by satellite data, overnight temperatures bottom out around negative one-hundred and thirty-five degrees Fahrenheit. These are the coldest conditions ever recorded on Earth.

Earth, though, is a hospitable planet. For true frigidity, look to the outer solar system. Triton, an icy pink moon orbiting the gas giant Neptune, clocks in at nearly four hundred degrees below zero! On its surface, alien volcanoes blast their gaseous guts out in jets up to five miles high. The volcanic ejecta crystallize immediately and snow down to the frozen world far below. Evidence from Voyager 2 indicates that these giant plumes are mostly made up of nitrogen– the main ingredient in the air you’re breathing right now!

LNstairsTriton

Global color mosaic of Triton, documented by Voyager 2, 1989. Geyser plumes are visible as dark streaks.

Source: http://www.jpl.nasa.gov/spaceimages/details.php?id=PIA00317

At three hundred and twenty-one degrees below zero, liquid nitrogen is colder than the most frigid Arctic night. It’s a cryogenic substance that would fit in with Triton’s weather better than our own. Nitrogen on Earth is usually a gas, but it’s possible to condense it into liquid form in the lab. As you can imagine, when air meets liquid nitrogen, its cools down fast. Water molecules in the chilled air condense into droplets visible as clouds or fog.

This might sound familiar! It’s closely related to the mechanism that causes clouds to form in the sky, a process we modeled in the lab not too long ago. Clouds are born when air cools down enough for suspended water molecules to condense. This is why you see fog when you push a warm breath from your lungs out into the atmosphere on a cold day, or when you bring something cold into contact with warm air.

Humid air, ripe with plenty of water molecules, produces extra-thick fog. Check out the cloud cover created by introducing liquid nitrogen into a damp poolside environment!

LNstairs3
*All temperatures quoted are in degrees Fahrenheit.

We Set Fire to the Clouds

This isn’t your typical cloud, and not just because it’s trapped inside a bottle! We chose rubbing alcohol as the raw material for our homemade tabletop cloud because it vaporizes so easily:

FireBottle1

Rubbing alcohol is also highly flammable. Let’s explore this property by creating some combustion reactions! Every fire (or combustion reaction) requires fuel, an oxidizing agent (like oxygen), and activation energy. Activation energy is the trigger that causes the combustion reaction to start.

In this experiment, we touch a flame to the top of a cloud of fuel (rubbing alcohol vapor). The vapor is suspended in air, so there’s plenty of oxygen present. Heat from the lighter causes the closest alcohol molecules to react with nearby oxygen molecules. As they react, their atoms recombine to form carbon dioxide and water vapor. These products tie up less energy than the original materials; the leftover energy is released in the form of visible light and heat. Newly generated heat provides activation energy for the next layer of combustion reactions, and the process continues until all of the fuel has been consumed.

FireBottle2

Isopropyl alcohol naturally burns blue, but it’s easy to change the hue of a flame. Just add salt! What our eyes interpret as colors are really waves of light stretched out to varying degrees. We say that the most stretched-out waves have the longest wavelength. We call the longest wavelengths we can see “red” and the shortest “violet”. A substance’s chemistry determines the wavelength– and thus the color– of the light that will be released by its combustion. Copper-based salts burn green. Strontium turns flames bright red. Sodium salts, such as table salt, burn yellow. If you’ve ever seen a multicolored fireworks show, you’ve experienced this science firsthand!

FireBottle3

Stacking Liquids with the Density Column

Why do these liquids stack so cleanly? For the same reason that helium floats on air, and air floats on water: it’s all about density. Density, or mass per volume, measures how much stuff is squeezed into a given space. The higher the mass-to-volume ratio, the denser the object. A ten-gallon bucket of rocks occupies the same amount of space as a ten-gallon bucket full of air, but it contains more mass– it’s more dense. Unsurprisingly, the bucket of rocks also feels heavier. Mass and weight are closely related! Denser substances are heavier by volume, so they sink beneath less dense substances. We can layer household substances of different densities to get a crazy stack of liquids!


Density1

The corn syrup is the most dense of our layers because there’s more “stuff” squeezed into a cubic inch of corn syrup than a cubic inch of maple syrup, whole milk, or any of the other density column ingredients. Weigh a fluid ounce of each liquid and you’ll find that corn syrup is the heaviest. It makes sense that it should sit at the bottom of the stack!

Density2

Trying this at home? For best results, pour slowly, and avoid letting the liquids run down the sides of the container. Adding your liquids in order from densest to least dense will also help to keep the layers cleanly separated.

For more info on density and buoyancy, check out our Coke vs Diet Coke experiment here!

Aerodynamics, Fire, & the Coanda Effect

Imagine a torpedo in a wind tunnel. Incoming air slips around the torpedo’s nose, slides along its surface, and flies off its blunt back end. The air stream can’t navigate sharp corners, but as long as a smooth contour is available, it clings to that curve. This is called flow attachment, or the Coanda effect.

Coanda1

The Coanda effect on an airplane wing.


Image source: http://cdn.theatlantic.com/static/mt/assets/jamesfallows/angleOfAttack.jpg

A fluid is anything that can flow freely– think water or air. Thanks to the Coanda effect, we can get a stream of fluid to go anywhere we want by giving it a smooth surface to follow. Helicopters and other VTOL aircraft use this principle to enhance lift! If a blade contour is smooth everywhere except a single edge, then that edge is where passing air slides off (just like in the image above). If the edge is angled towards the ground, then the air moves downward as it leaves the blade surface. Every action has an equal and opposite reaction; in this case, the downward momentum of the air translates to upward momentum of the aircraft. This isn’t the main way that airplanes gain altitude (that’s the Bernoulli effect), but it’s a useful way to improve performance. The Coanda effect can triple the Bernoulli lift on a blade or wing!

Coanda2

In this experiment, we put a cylindrical container in the path of a breath of air and attempt to blow out a candle on the other side. The air stream splits in two and follows the curved surface. There’s no sharp edge for the two halves to slide off of, so they hug the contour of the obstacle until they run into each other on the far side. The collision redirects the flow, causing a burst of air to continue on past the cylinder– almost as if it wasn’t there.

coanda3

Try it for yourself with a round container and a candle! Please use adult supervision testing experiments using fire.

Experimenting with Hand Warmers: Its Hot

Your body knows that internal organs are more vital than, say, fingers and toes. In cold weather, it wouldn’t be very efficient to pump warm blood to the outside of your body, because then the heat could easily radiate away! Conserving warmth in your core is a great survival tactic, but it’s uncomfortable for the body parts that aren’t receiving as much circulation. Luckily, science has a solution! We’ve seen it before. We’ll see it again. It’s one of the most wildly useful concepts in chemistry! Let’s take another look at exothermic reactions.

HandWarmer1
Switching views between a regular and an infrared camera allows us to see the crystallization reaction in terms of both heat and visible light.

Reusable hand warmers are a great everyday example of exothermic behavior. These handy pocket heaters rely on liquid sodium acetate to produce warmth. The liquid is supersaturated– it’s on the verge of crystallizing. When we trigger a crystallization reaction, the sodium acetate changes from liquid (higher energy) to a crunchy near-solid (lower energy). The leftover energy has to go somewhere. It’s released as heat!

HandWarmer2

The rectangular mark you see here is invisible to the naked eye. The infrared camera, however, “sees” the warm area where the hand warmer contacted the skin!

Sodium acetate releases heat energy as it solidifies. To return a hand warmer to its original, liquid state, all we have to do is put the energy back. Submerge the used hand warmer in boiling water, and the added heat reverses the crystallization reaction! Energy-consuming reactions like this one are called endothermic. After boiling, the packet is back in its original higher-energy state, ready to start the process all over again the next time cold weather strikes.

Hydrophobic Nanotech: Magic Sand

You’ve probably seen how oil and water get along (or don’t), but did you know that this behavior could help control oil spills and alleviate desert water shortages? Oil isn’t the only substance that doesn’t want to associate with water. One innovation that has harnessed the power of water resistance is hydrophobic (“water-fearing”) sand. Sand1

Marketed as Magic Sand in the toy industry and Nano Sand for more practical purposes, hydrophobic sand begins as normal beach dust. A trimethylsilanol vapor treatment coats the grains in non-polar molecules –– the same kind of molecules oil is composed of — making them unlikely to interact with water. You can actually see a silvery coat of air form around the sand when it’s submerged!

Sand2

So, why does this work? Let’s think for a moment about what polar and non-polar mean. Water is a great example of a polar molecule! Here’s a picture of the basic structure of H2O:

h2o

Image courtesy of http://butane.chem.uiuc.edu/pshapley/Enlist/Labs/Clouds/Clouds.html.

As you can see, it’s not symmetric. The two hydrogen atoms (white) lean off to one side of the oxygen atom (red). In water, oxygen has a partial positive charge and hydrogen a partial negative charge. The offset position of these atoms gives the water molecule one positive side, where the oxygen sticks out, and one negative side, where the two hydrogens sit next to each other. In other words, the molecule has two poles. It’s polar! You’ve heard the phrase opposites attract. Water molecules are perfectly constructed to bind with other molecules that have positive and negative poles. Molecules without poles, however, are immune to this electromagnetic attraction. We call these kinds of molecules — you guessed it — non-polar. Non-polar molecules don’t have a positive or negative end. Try as you might to get them to bind with polar molecules, the two won’t mix. You’ll always end up with large clumps of polar molecules, large clumps of non-polar molecules, and not much interaction between the two.

Sand3

This assortative behavior has fantastic real-life applications. Mix non-polar hydrophobic sand with non-polar petroleum from an oil spill, and they’ll bind seamlessly until the mixture grows heavy enough to sink. This fix is currently too expensive for widespread use, but the science is solid.

Several years ago, hopes were high for water-repellent sand to act as an artificial water table below the topsoil in desert areas where agriculture is prevalent. The hydrophobic layer would increase time between waterings and protect plant roots from salts in the deeper soil. Promising as it sounds, there hasn’t been much recent news about this application. Magic Sand seems to be relegated to the toy industry for now… at least until the next time an engineering team gets hooked by its world-changing potential.

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We would like to thank you for visiting our blog. AstroCamp is a hands-on physical science program with an emphasis on astronomy and space exploration. Our classes and activities are designed to inspire students toward future success in their academic and personal pursuits. This blog is intended to provide you with up-to-date news and information about our camp programs, as well as current science and astronomical happenings. This blog has been created by our staff who have at least a Bachelors Degree in Physics or Astronomy, however it is not uncommon for them to have a Masters Degree or PhD. We encourage you to also follow us on Facebook, Instagram, Google+, Twitter, and Vine to see even more of our interesting science, space and astronomy information. Feel free to leave comments, questions, or share our blog with others. Please visit www.astrocampschool.org for additional information. Happy Reading!

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