The Halloween Science FAQ

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.
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A standard white 5-gallon plastic bucket allowed for 20 lbs of candy in 675 pieces.
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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.
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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 City-Data.com 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 MyScienceProject.com. They've got some fabulous stuff on their site. Who among us hasn't wondered whether Viagra keeps flowers fresh?]

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These Sparrows Have Been Singing the Same Songs for 1500 Years
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Swamp sparrows are creatures of habit—so much so that they’ve been chirping out the same few tunes for more than 1500 years, Science magazine reports.

These findings, published in the journal Nature Communications, resulted from an analysis of the songs of 615 adult male swamp sparrows found in six different areas of the northeastern U.S. Researchers learned that young swamp sparrows pick up these songs from the adults around them and are able to mimic the notes with astounding accuracy.

Here’s what one of their songs sounds like:

“We were able to show that swamp sparrows very rarely make mistakes when they learn their songs, and they don't just learn songs at random; they pick up commoner songs rather than rarer songs,” Robert Lachlan, a biologist at London’s Queen Mary University and the study’s lead author, tells National Geographic.

Put differently, the birds don’t mimic every song their elders crank out. Instead, they memorize the ones they hear most often, and scientists say this form of “conformist bias” was previously thought to be a uniquely human behavior.

Using acoustic analysis software, researchers broke down each individual note of the sparrows’ songs—160 different syllables in total—and discovered that only 2 percent of sparrows deviated from the norm. They then used a statistical method to determine how the songs would have evolved over time. With recordings from 2009 and the 1970s, they were able to estimate that the oldest swamp sparrow songs date back 1537 years on average.

The swamp sparrow’s dedication to accuracy sets the species apart from other songbirds, according to researchers. “Among songbirds, it is clear that some species of birds learn precisely, such as swamp sparrows, while others rarely learn all parts of a demonstrator’s song precisely,” they write.

According to the Audubon Guide to North American Birds, swamp sparrows are similar to other sparrows, like the Lincoln’s sparrow, song sparrow, and chipping sparrow. They’re frequently found in marshes throughout the Northeast and Midwest, as well as much of Canada. They’re known for their piercing call notes and may respond to birders who make loud squeaking sounds in their habitat.

[h/t Science magazine]

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18 Smart Products To Help You Kick Off Summer
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Whether you’re trying to spiff up your backyard barbeque or cultivate your green thumb, these summertime gadgets will help you celebrate the season from solstice to the dog days.

1. ROSÉ WINE GLASSES; $60

Rosé Wine Glass
Amazon

Why It’s Cool: Wine not? When the temperature rises and beer isn’t your thing, reach for the rosé. Riedel’s machine-blown SST (see, smell, taste) wine glasses will give the sparkly stuff ample room to breathe, making every refreshing sip worthwhile.

Find It: Amazon

2. NERF N-STRIKE ELITE SURGEFIRE; $25

Nerf SurgeFire
Hasbro

Why It’s Cool: The N-Strike Elite SurgeFire (say that five-times-fast) sports a pump-action rotating drum for maximum foam-based firepower and holds up to 15 Nerf darts in its arsenal.

Find It: Hasbro Toy Shop

3. BUSHEL & BERRY PLANTS; $34

plant
Amazon

Why It’s Cool: You don’t need to have a green thumb to create a brag-worthy garden this summer. Besides producing snackable mid-season berries, these open-growing bushes can be planted immediately for easy set-up to make you look like a botanical pro.

Find It: Amazon

4. INFLATABLE DONUT; $17

Doughnut float
Amazon

Why It’s Cool: When the only dunking you’re doing is taking a dip in the pool, a 48-inch inflatable donut is the perfect way to stay afloat.

Find It: Amazon

5. STAR SPANGLED SPATULA; $21

American flag spatula
Amazon

Why It’s Cool: O say can you see by your grill’s charcoal light / Meats so proudly we cooked ... with a star spangled spatula. Depending on the specific model, these all-American grilling tools (designed in New Jersey and made in Chicago) are made of a combination of walnut and stainless steel or nylon. As an added bonus: 5 percent of the proceeds go to the Penn Abramson Cancer Center.

Find It: Amazon

6. MLB HOT DOG BRANDERS; $8 AND UP

MLB San Diego Padres Hot Dog BBQ Brander
Amazon

Why It’s Cool: Take your hot dogs, sausages, brats, and more out to the ballgame without ever leaving your grill. These branders from Pangea Brands are dishwasher-safe and made of ceramic-coated cast iron.

Find It: Amazon

7. UNA GRILL; $139

grill
MoMA Shop

Why It’s Cool: This portable charcoal-heated grill is as efficient as it is stylish. The compact size lets you cook at the park, after hitting up MoMA, or anywhere in between.

Find It: MoMa Shop

8. HAMBURGER GRILLING BASKET; $21


Why It’s Cool: Made of steel and finished with a non-stick coating, this grilling tool flips four burgers at once and maintains perfect burger proportions to guarantee nobody stays hungry for long.

Find It: Amazon

9. COPPER FIRE PIT; $121

metal fire pit
Amazon

Why It’s Cool: The grill isn’t the only place for a roaring fire this summer. This 100 percent solid copper fire pit makes for the perfect gathering spot at your next BBQ, or just to warm up after a cool summer evening.

Find It: Amazon

10. BENDY STRAW POOL NOODLE FLOAT; $10

Bendy Straw Inflatable Pool Float
Amazon

Why It’s Cool: Inflatable pool floats shouldn’t be boring, and this bendy straw float definitely does not suck. This unique spin on traditional pool noodles is sure to make for some cheesy jokes, but at least you’ll be comfortable floating in the pool or at the beach.

Find It: Amazon

11. GRIDDLER DELUXE; $111

Cuisinart GR-150 Griddler Deluxe
Amazon

Why It’s Cool: If you’re looking for some serious panini power, this griddler offers up a versatile lineup of six cooking options in one. And with dual-zone functions you can sling burgers while searing filets and sautéeing vegetables all at the same time.

Find It: Amazon

12. VINTAGE SNOW CONE MAKER; $30

Vintage Snow Cone Maker
Amazon

Why It’s Cool: With its old-timey design, dual cone shelf, and endless flavor options, this snow cone maker is guaranteed create a cool treat.

Find It: Amazon

13. DACHSHUND CORN ON THE COB HOLDERS; $7

Dog Corn Holders
Amazon

Why It’s Cool: While meat-lovers will inevitably scarf down a lot of hot dogs this summer, vegetarians who happen to love another kind of dog will be smitten with these stainless steel, Dachshund-shaped corn on the cob prongs. They’re a fun spin on a summer grilling favorite.

Find It: Amazon

14. ICE CREAM SANDWICH MAKER; $16

Ice Cream Sandwich Maker
Amazon

Why It’s Cool: Four sandwiches are better than one, especially when they're of the ice cream variety. Make four ice cream sandwiches at once with this homemade spin on a classic cold treat.

Find It: Amazon

15. UE WONDERBOOM; $68

Bluetooth speaker
Amazon

Why It’s Cool: Besides delicious food and great company, some memorable tunes are required for the quintessential barbeque. This portable bluetooth speaker offers up some booming sound in a small package, and with a battery power of 10 hours on a single charge you can keep the party going all night.

Find It: Amazon

16. ROLLORS GAME; $38

Rollors Backyard Game
Amazon

Why It’s Cool: When you’re sick of bocce, hate horseshoes, and you’re over cornhole, you might want to take up “rollors,” a family-friendly game that combines your favorite traditional backyard festivities into one game for people of all ages.

Find It: Amazon

17. HAMMOCK; $174

hammock
Amazon

Why It’s Cool: Rest easy knowing that this 100 percent hand-woven and hand-dyed cotton hammock contributes to artisan job-creation in Thailand.

Find It: Amazon

18. VSSL SURVIVAL ESSENTIALS; $59

Emergency Survival Tent Outdoors
Amazon

Why It’s Cool: Compact, convenient, and durable, the VSSL Shelter can come in handy when things don’t go quite as planned. The device—which features a lightweight emergency shelter all within the handle of a compact, weather-resistant aluminum LED flashlight—is designed to keep you safe under the worst conditions.

Find It: Amazon

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