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The Halloween Science FAQ

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What is dry ice and how does it make that awesome fog?

Dry ice is the colorless, odorless, solid form of carbon dioxide, first reported in 1834 by the French chemist Charles Thilorier, who opened a container of liquid carbon dioxide needed for an experiment and observed that most of the liquid CO2 quickly evaporated, leaving a solid form on the bottom of the canister.

The surface temperature of dry ice is −109.3 °F. As it warms up, it sublimes, or transitions from the solid to gas form with no intermediate liquid form (a process called sublimation). These two characteristics make it an excellent coolant and since 1925, when solid CO2 was trademarked and sold as "Dry ice" by the DryIce Corporation of America, it's been used to flash freeze and refrigerate food and biological samples, make ice cream, bait mosquito traps (they're attracted to CO2) and make fog for theater productions, Sunn O))) concerts and haunted houses.

That fog is made by quickly changing the CO2 into its gas form. In an ice chest, dry ice sublimes at an average rate of 5-10 pounds every 24 hours. But placing dry ice in hot water accelerates sublimation considerably and turns the solid CO2 into CO2 gas. The cold CO2 gas meets the surrounding air and drops its temperature enough for condensation to occur and tiny droplets of water to form in the air and, voila, you have fog. Because carbon dioxide is heavier than air, and cold air is denser than warm air, the fog stays low to the ground for that extra creepy effect.

Why do we get goosebumps?

Goose bumps, also called goose flesh or goose pimples and known to medical professionals as cutis anserina ("cutis," skin + "anser," goose = goose skin) involuntarily develop on our skin when we become cold or experience strong emotions in a reflex called horripilation or piloerection. Whether we're freezing or getting the bejesus scared out of us, our sympathetic nervous systems pick up on a fight-or-flight situation and release adrenaline, muscles at the base of our body hairs contract, pull the hair erect, and create a shallow depression on the skin surface that causes the surrounding area to protrude. A goose bump is born.

In mammals with plenty of body hair or fur (chimps, otters, mice, cats, etc.), horripilation serves two purposes. One, erect hairs trap air, create insulation and aid heat retention. Two, erect hairs make an animal appear larger and helps intimidate enemies. In humans, horripilation as a response to cold or fear provides no known benefit since we lost most of our body hair some time ago.

What's the best candy container for trick-or-treating?

hwcandy_03What sort of container will provide you with maximum space for your candy haul? A bucket? A bag? The ol' pillow case? The guys (Guys? Gals? Robots? Not a whole lot of info available on who runs it.) at My Science Project conducted an experiment to find out.

First, the researchers accounted for the wide variety of candies available to the average trick-or-treater. They divided candy into three categories: ""˜premium' (fun-sized candy bars), "˜meh' (chewy boxed candies like Milk Duds), and "˜bottom of the barrel' (hard candy, gumballs, Dum Dum pops)," mixed roughly equal amounts by weight of top, middle, and bottom tier candies, and threw them into the containers by the handful, in order to give the candy a natural spatial distribution.

Each container was filled to a capacity where it could be reasonably carried without spilling and then weighed on a hanging spring scale (adjusted to account for the weight of the container).

Their results"¦

A 10-quart bucket held a total of 9.5 lbs of candy, consisting of 375 pieces.
A standard white 5-gallon plastic bucket allowed for 20 lbs of candy in 675 pieces.
A double-bagged, regular brown paper grocery bag held 25 lbs of candy, consisting of 885 pieces. The researchers found that the bag's unreliable handles were problematic once the bag was full.
A standard size pillow case, allowing enough empty room at the top so that it may be grasped and picked up with two hands, held a whopping 47.75 lbs of candy in the form of 1690 pieces.

Next, they wanted to know if it would be possible to even collect that much candy in one night of trick-or-treating. How far would one need to walk and how many houses would they have to hit?

The researchers picked two different middle-class residential areas representative of suburban America at large to use in the experiment. Campbell, California, in Silicon Valley is an older area with dense housing, and St. Peters, Missouri, a suburb of St. Charles, is more rural and contains many newer developments. The researchers used data from to approximate the number of houses per square mile and constructed several different trick-or-treating scenarios, varying the values for the number of candies received at each house, and the percentage of houses distributing candy. In their worst case scenario, they figure a trick-or-treater would have a 50% success rate and receive an average of 2.5 pieces of candy per house, while a decent trick-or-treating run would see a 75% success rate and 3.5 pieces of candy per house.

They researchers then used Google maps to work out what sort of mileage a candy hunter would have to clock. Assuming the first scenario, a trick-or-treater would have to visit approximately 1352 houses and cover .42 square miles in Campbell, given the housing density, to fill their pillowcase. Under the more favorable conditions of the second scenario, it would take visits to 644 houses and .2 square miles to fill a pillowcase. Looking at the their map, the researchers estimated roughly 1 linear mile of street distance per every .036 square miles, meaning one would walk about 11 miles to fill their candy bag in the worst case scenario.

In the better scenario in St. Peters, the lower density of housing necessitates that someone cover .6 square miles to fill a pillowcase. That's more walking than in the worst case scenario in Campbell—and since the researchers' housing densities are based on statistical averages and don't account for undeveloped land, a trick-or-treater would likely need to cover a lot more ground. [Image courtesy of They've got some fabulous stuff on their site. Who among us hasn't wondered whether Viagra keeps flowers fresh?]


Google Street View Now Lets You Explore the International Space Station

Google Street View covers some amazing locations (Antarctica, the Grand Canyon, and Stonehenge, to name a few), but it’s taken until now for the tool to venture into the final frontier. As TechCrunch reports, you can now use Street View to explore the inside of the International Space Station.

The scenes, photographed by astronauts living on the ISS, include all 15 modules of the massive satellite. Viewers will be treated to true 360-degree views of the rooms and equipment onboard. Through the windows, you can see Earth from an astronaut's perspective and a SpaceX Dragon craft delivering supplies to the crew.

Because the imagery was captured in zero gravity, it’s easy to lose sense of your bearings. Get a taste of what ISS residents experience on a daily basis here.

[h/t TechCrunch]

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Lucy Quintanilla/iStock
6 East Coast Castles to Visit for a Fairy Tale Road Trip
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Lucy Quintanilla/iStock

Once the stuff of fairy tales and legends, a variety of former castles have been repurposed today as museums and event spaces. Enough of them dot the East Coast that you can plan a summer road trip to visit half a dozen in a week or two, starting in or near New York City. See our turrent-rich itinerary below.


59 miles from New York City

The crumbling exterior of Bannerman Castle
Garrett Ziegler, Flickr // CC BY-NC-ND 2.0

Bannerman Castle can be found on its very own island in the Hudson River. Although the castle has fallen into ruins, the crumbling shell adds visual interest to the stunning Hudson Highlands views, and can be visited via walking or boat tours from May to October. The man who built the castle, Scottish immigrant Frank Bannerman, accumulated a fortune shortly after the Civil War in his Brooklyn store known as Bannerman’s. He eventually built the Scottish-style castle as both a residence and a military weapons storehouse starting in 1901. The island remained in his family until 1967, when it was given to the Taconic Park Commission; two years later it was partially destroyed by a mysterious fire, which led to its ruined appearance.


116 miles from Beacon, New York

William Gillette was an actor best known for playing Sherlock Holmes, which may have something to do with where he got the idea to install a series of hidden mirrors in his castle, using them to watch guests coming and going. The unusual-looking stone structure was built starting in 1914 on a chain of hills known as the Seven Sisters. Gillette designed many of the castle’s interior features (which feature a secret room), and also installed a railroad on the property so he could take his guests for rides. When he died in 1937 without designating any heirs, his will forbade the possession of his home by any "blithering sap-head who has no conception of where he is or with what surrounded.” The castle is now managed by the State of Connecticut as Gillette Castle State Park.


74 miles from East Haddam, Connecticut

The exterior of Belcourt castle
Jenna Rose Robbins, Flickr // CC BY-SA 2.0

Prominent architect Richard Morris Hunt designed Belcourt Castle for congressman and socialite Oliver Belmont in 1891. Hunt was known for his ornate style, having designed the facade of the Metropolitan Museum of Art and the Breakers in Newport, Rhode Island, but Belmont had some unusual requests. He was less interested in a building that would entertain people and more in one that would allow him to spend time with his horses—the entire first floor was designed around a carriage room and stables. Despite its grand scale, there was only one bedroom. Construction cost $3.2 million in 1894, a figure of approximately $80 million today. But around the time it was finished, Belmont was hospitalized following a mugging. It took an entire year before he saw his completed mansion.


111 miles from Newport, Rhode Island

Part of the exterior of Hammond castle
Robert Linsdell, Wikimedia Commons // CC BY 2.0

Inventor John Hays Hammond Jr. built his medieval-style castle between 1926 and 1929 as both his home and a showcase for his historical artifacts. But Hammond was not only interested in recreating visions of the past; he also helped shape the future. The castle was home to the Hammond Research Corporation, from which Hammond produced over 400 patents and came up with the ideas for over 800 inventions, including remote control via radio waves—which earned him the title "the Father of Remote Control." Visitors can take a self-guided tour of many of the castle’s rooms, including the great hall, indoor courtyard, Renaissance dining room, guest bedrooms, inventions exhibit room, library, and kitchens.


430 miles from Gloucester, Massachusetts

It's a long drive from Gloucester and only accessible by water, but it's worth it. The German-style castle on Heart Island was built in 1900 by millionaire hotel magnate George C. Boldt, who created the extravagant structure as a summer dream home for his wife Louise. Sadly, she passed away just months before the place was completed. The heartbroken Boldt stopped construction, leaving the property empty for over 70 years. It's now in the midst of an extensive renovation, but the ballroom, library, and several bedrooms have been recreated, and the gardens feature thousands of plants.


327 miles from Alexandria Bay, New York

Part of the exterior of Fonthill castle

In the mood for more castles? Head south to Doylestown, Pennsylvania, where Fonthill Castle was the home of the early 20th century American archeologist, anthropologist, and antiquarian Henry Chapman Mercer. Mercer was a man of many interests, including paleontology, tile-making, and architecture, and his interest in the latter led him to design Fonthill Castle as a place to display his colorful tile and print collection. The inspired home is notable for its Medieval, Gothic, and Byzantine architectural styles, and with 44 rooms, there's plenty of well-decorated nooks and crannies to explore.


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