March 29, 2013
If the Easter Bunny comes to your house this weekend, you may find yourself with a plethora of marshmallows and Peeps. What to do with them all? Aside from simply eating them, cooking with them, or unleashing your artistic side by making dioramas, consider using them….for science!
Marshmallows, it turns out, are must-have pieces of equipment for at-home science experiments. Sure, you can use them test your kids’ self control through the the field of psychology’s notorious marshmallow test and its ever-more complex iterations. But if you’d rather not torture your kids by leaving tantalizingly in reach a marshmallow they’re ordered not to have, consider trying these easy science projects:
Marshmallows in a vacuum
No, not that kind of vacuum, despite the intriguing possibilities conjured by this phrase. You’ll need:
- A glass jar with a lid
- A mechanism to pump some of the air out of the jar
Place a few marshmallows in the jar, seal it, and then pump the air out:
What’s going on? Marshmallows are basically a foam spun out of sugar, water, air, and gelatin. The sugar makes them sweet, the water and sugar combo makes them sticky and the gelatin makes them stretchy. But the air–which actually makes up most of the confection’s volume–makes marshmallows the tastiest way to encapsulate a gas in a solid. As you pump air out of the jar, the air inside the marshmallow expands and the marshmallow puffs up. Release the seal, and the marshmallows return to their normal size.
Congratulations! You’ve just demonstrated Boyle’s Law, which states that when the temperature doesn’t change, that the relationship between pressure (which is decreased by pumping air out of the jar) and volume of any set amount of gas (the marshmallow) is inversely proportional. In other words, decreasing one necessitates an increase of the other.
If you can’t eat ‘em, nuke ‘em!
If you’ve ever roasted a marshmallow over a campfire, you’ll know where this next demonstration is going. You’ll need:
- A microwave
- A microwavable plate
- A standard-sized marshmallow (avoid minis or jumbos; the former will fry and the latter may make an enormous mess!)
Place the marshmallow on one of its flat sides in the center of a plate. Then microwave the marshmallow for, say, 45 seconds on high.
It’s alive! This time, rather than changing the pressure surrounding the marshmallow, you’re changing the temperature. As the microwave bakes the marshmallow, the water in the marshmallow heats up and warms the air. When air becomes hot, it expands, forcing the marshmallow to puff up. The confection’s water also softens the sugars, causing it to ooze, as seen in the video above (created by YouTube user bbbpwns).
The relationship between temperature and volume is representative of Charles’ Law, which holds that any set amount of gas will expand when heated–increasing the temperature of a gas necessitates an increase in the gas’ volume.
Trying this with Peeps makes for a slightly alarming outcome, showcased by YouTube user UBrocks:
If you flashed back to the Stay Puft Marshmallow Man, alas–the monster marshmallow you pulled from your microwave doesn’t last–it will cool and deflate into a glob of ooze. But before it cools completely, the ooze is quite malleable and can be sculpted into shapes. But careful! The marshmallow remnants are like naplam–they’ll stick to you and burn. After it cools a bit, brush some oil on your palms before you mold anything, else your sculpture will stay glued to your hands.
A gooey way to calculate the speed of light
For this demonstration you need a bit of background knowledge as you start out. The speed of a wave can be calculated by multiplying the wavelength (the distance from crest to crest) with the frequency (the number of crest-to-crest cycles that repeat in a stretch of time). Light is a wave, and its speed can be calculated the same way without fancy equipment. You’ll need:
- A microwave with the turntable removed
- A glass casserole dish or baking tray
- Mini marshmallows
- A ruler
- A calculator
Take the baking tray and pack one layer of marshmallows along the bottom, lined up like tiny puffy soldiers. Make sure the turntable is removed from the microwave–this allows microwaves to move through the glass and the marshmallows in a standing wave pattern. Cook for a few minutes on low, watching the marshmallows carefully. With the turntable removed, the microwave doesn’t heat evenly–you’ll notice melted patches forming in your marshmallow field.
As soon as you see a few such patches, remove the dish and measure the distance between two that form a line parallel to the microwave’s door–these mark the locations of highest amplitudes within the standing wave. Multiply this by two to get the full wavelength of the microwaves that passed through your marshmallows (if you look at the geometry of a standing wave, your initial measurement only gave you half the wavelength). Convert this into meters.
Multiplying this result by frequency of the microwave, found in the microwave’s manual or in a label inside the device, gives ~299,000,000 meters per second–roughly speed of light! Catch a video of this here.
April 17, 2012
At the Monterey Bay Aquarium, jellyfish are a fan favorite—as long as the stinging swimmers are behind glass. Something about the even pulsing of the delicate, bell-shaped creatures has a calming effect on visitors. Some even say their heart rates slow when watching the jellies.
It is this trance-inducing quality that helped inspire the aquarium’s new 1960s-themed, Jimi Hendrix-esque exhibition: “The Jellies Experience.” The show, open through September 2014, is the latest chapter in the aquarium’s history of cultivating and exhibiting jellyfish. In 1985, the Monterey facility became a pioneer in jellyfish display when it exhibited moon jellies for the first time. Seven years later, the aquarium staged “Planet of the Jellies,” its first all-jellies exhibition. A permanent jellies gallery opened in 1996, as part of the Open Sea wing, and in 2002, the aquarium hosted “Jellies: Living Art,” another temporary show. But “The Jellies Experience,” says Raúl Nava, an exhibit developer and writer at the aquarium, is by far the most interactive.
Nava recently gave me a tour. We walked through the exhibit’s six rooms, each centered on a different aspect of jellyfish—their movement, body structure, stinging capabilities, diversity, possible population booms and bioluminescence. Hands-on elements along the way give a sense of what it is like to be a jelly. Press down on one of three waist-high columns in one room, for instance, and you can control the image of a jelly pulsing across a screen. Stand in front of a camera mounted in the wall in another gallery and see a kaleidoscopic image of yourself that mimics a jellyfish’s radial symmetry. Draw a digital jellyfish on a touch screen and free it into a virtual ocean, along with other visitors’ creations. And walk through a mirrored room with three cylindrical tanks of live jellies to experience the illusion of being in a swarm of jellyfish.
The interactive features, however, do not outshine the 16 species of live jellies displayed. Exhibit designer Koen Liem came up with the show’s psychedelic vibe, but as he says, ”the animals are the real stars.” From Japanese sea nettles to upside-down jellies, flower hat jellies to cross jellies and blubber jellies, the creatures, some raised at the aquarium and others collected, are mesmerizing. I found myself studying them and their intricate details—crimped tentacles, fluorescent colors, stripes and spots.
Here are 14 fun facts about jellies:
1) A group of fish is called a school. A gathering of dolphins is a pod. Several otters makes up a romp. And an assemblage of jellies is a swarm or, better yet, a smack.
2) “Swarm” and “bloom” should not be used interchangeably when talking about jellies. A swarm refers to jellies that collect in one area as a result of strong winds or currents, whereas a bloom is a dense cloud of jellies caused by an actual spike in reproduction.
3) Jellies are 95 percent water.
4) Musician Frank Zappa is the namesake of one species of jelly, Phialella zappai. (For an explanation, see Smithsonian writer Abigail Tucker’s story, “Extreme Jellyfish.”)
5) Though jellies are soft-bodied and lack a skeleton, making fossils rare, there is evidence that jellyfish predate dinosaurs by some 400 million years.
6) A historic moment for jellyfish came in May 1991, when 2,478 moon jelly polyps and babies were launched into space aboard the shuttle Columbia. Biologist Dorothy Spangenberg of the Eastern Virginia Medical School wanted to learn about how weightlessness affected the development of juvenile jellies. She monitored calcium loss in the jellies, which by extension could further scientists’ understanding of humans’ calcium loss in space.
7) Some jellyfish, such as blubber jellies, a delicacy in parts of Asia, are edible. A former colleague wrote about her culinary adventure tasting jellyfish in Washington D.C.’s Chinatown.
8) Most jellyfish live anywhere from a few hours to a few months. But a species of jelly called Turritopsis nutricula may be immortal. The jelly reportedly can play its lifecycle in reverse, transforming from an adult medusa back to an immature polyp.
9) Jellies have been known to eat other jellies.
10) The creatures lack not only bones, but heads, hearts and brains.
11) Researchers from the Monterey Bay Aquarium Research Institute surmise that cross jellies (Mitrocoma cellularia), common to Monterey Bay in the spring and summer, can “smell” prey through chemicals in the water.
12) A recent study found that four of the box jellyfish Tripedalia cystophora‘s 24 eyes always point up. The jellyfish looks through the water surface for tree branches. This way, it can swim towards mangrove swamps where it feeds.
13) GFP, a green fluorescent protein found in crystal jellies, has important medical applications. Mayo Clinic scientists recently inserted a version of GFP and a gene from a rhesus macaque known to block a virus that causes feline AIDS into a cat’s unfertilized eggs. When the kittens were born, they glowed green in ultraviolet light, indicating that the gene was successfully transferred. Biologist Osamu Shimomura won a Nobel Prize in Chemistry in 2008 for discovering GFP.
14) Jellyfish can sting even when they are dead. In 2010, about 150 swimmers at Wallis Sands State Park in New Hampshire were stung by the floating, 40-pound carcass of a lion’s mane jellyfish.
December 8, 2011
On the night of May 22, 1453, the people of Byzantium could see an eerie red shadow cross the Moon. It was a partial eclipse–the Earth had gotten in between the Sun and Moon–and the Byzantines took it as a bad omen. And perhaps they were right–the city of Constantinople fell before the month’s end.
A full lunar eclipse will take place this weekend, visible from Asia, Australia and western North America. But people today don’t view this astronomical event as a worrying sign. Instead, it’s time for science! And you can participate.
The Classroom Astronomer magazine has set up a website, measurethemoon.org, to coordinate observations of the position of the moon in the sky as it passes through our planet’s shadow. And if you’re in the right place, you can measure the distance from the Earth to the Moon.
There are two ways to do this. The first is called the Shadow Method, and it’s the way that the ancient Greeks first measured the distance between the Earth and Moon thousands of years ago. Amy Shira Teitel explains in Universe Today:
Start with the few knowns. We know, as did the Ancient Greeks, that the Moon travels around the Earth at a constant speed—about 29 days per revolution. The diameter of the Earth is also known to be about 12,875 kilometers, or 8,000 miles. By tracking the movement of the Earth’s shadow across the Moon, Greek astronomers found that the Earth’s shadow was roughly 2.5 times the apparent size of the Moon and lasted roughly three hours from the first to last signs of the shadow.
From these measurements, it was simple geometry that allowed Aristarchus (circa 270 B.C.) to determined that the Moon was around 60 Earth radii away (about 386,243 km or 240,000 miles). This is quite close to the currently accepted figure of 60.3 radii.
You can follow Aristarchus’ method in your own backyard if you have a clear view of a Lunar eclipse. Track the movement of the Earth’s shadow on the Moon by drawing the changes and time the eclipse. Use your measurements to determine the Moon’s distance.
The second method, the Lunar Parallax Method, was familiar to the ancient Greeks but they lacked the ability to communicate over the far distances that is necessary to carry this out. Telephones and the Internet make this easily possible now. Two observers at least 2,000 miles apart will have to snap a picture of the Moon at the exact same moment. Because the angle at which the Moon and the stars behind it will be different for each person, the images they snap will be slightly different, particularly the stars in the background. “What your images have given you is a triangle,” Teitel explains. “You know the base (the distance between you and your friend), and you can find the angle at the top (the point of the Moon in this triangle). Simple geometry will give you a value for the distance of the Moon.”
If the people behind measurethemoon.org get enough participants, they’ll be able to compare all the various calculations, determine which method is more accurate and figure out how close two people have to be to get an accurate calculation with the Lunar Parallax Method.
If you’re not up for calculations, there are a few other lunar eclipse science projects you might want to participate in:
- Roger Sinnott of Sky & Telescope is collecting telescopic timings of the the passage of Earth’s shadow across lunar craters (find instructions here) as part of a long-term project to track the unpredictability of the diameter of the shadow.
- John Westfall of the Association of Lunar and Planetary Observers is collecting timings of when the phases of the lunar eclipse begin and end, made with the unaided eye, to calibrate similar observations made in the past when mariners used the Moon to determine longitude.
- Richard Keen of the University of Chicago will collect reports of the Moon’s brightness from amateur astronomers for use in volcano-climate studies.
After reading all this and seeing the picture above, you may be wondering why the Moon in a lunar eclipse turns red, not black. “That red light on the Moon during a lunar eclipse comes from all the sunrises and sunsets around the Earth at the time,” says Robert Naeye, editor in chief of Sky & Telescope. “If you were an astronaut standing on the Moon and looking up, the whole picture would be clear. The Sun would be covered up by a dark Earth that was ringed all around with a thin, brilliant band of sunset- and sunrise-colored light, bright enough to dimly light the lunar landscape around you.”
If, like me, you’ll miss out on this chance to see a lunar eclipse, your next opportunity will come in April 2014.
July 13, 2011
What does a music teacher do when he ends up teaching science? He teaches about evolution and the geologic timeline with music, of course, and that’s what Canadian elementary school teacher John Palmer did. He originally played “Cambrian Explosion” as a rock/hip hop creation in class but has since recorded an acoustic version. (The trio is called Brighter Lights, Thicker Glasses and consists of Palmer on the guitar/vocals, Michael Dunn on the dobro and Brian Samuels on the cello.)
Palmer tells us that former students can remember his “Cambrian Explosion” even a decade later. “It always floors me,” he writes. But that’s what great teachers do—they leave their students with both knowledge and the great memories that keep those bits stuck in our brains.
(Many thanks to John Palmer for bringing this to the magazine’s attention—we wouldn’t have wanted to miss it. You can find out more about the Cambrian Explosion and the Burgess Shale in the August 2009 issue of the magazine.)
June 24, 2011
“They’re not only racing across the world—they’re racing to save the world,” declares the trailer of the new movie Cars 2. The animated feature is the latest kids’ movie with an environmental twist: Alternative-fuel-advocating heroes will show down with big-oil villains as the movie hits theaters today. We rounded up the top ten kids’ movies aimed at spreading the word about saving the environment.
1) FernGully: The Last Rainforest — This 1992 animated film depicts a magical rainforest inhabited by fairies but threatened by destructive loggers. When the loggers cut down a tree and release the evil spirit Hexxus, Crysta, the fairy protagonist, and her friends (including lumberjack Zak, whom Crysta shrunk down to miniature size to save his life) must find a way to defeat the pollution-loving demon and save their home. The movie’s message is overtly conservationist, villainizing destructive humans and urging viewers to do what they can to preserve the wilderness areas still left on Earth.
2) WALL-E — This hit film from 2008 takes place 700 years in the future, when the Earth has been reduced to a deserted, trash-covered ghost town. Robot WALL-E seems to be the last sentient being on the planet, as all the humans have fled to gigantic space ships that hover in outer space. One day, one of those ships comes to Earth, bringing advanced robot EVE, with whom WALL-E falls in love. He follows her back to space, and his adventures there eventually convince the humans they must return to Earth. The state of the Earth in the movie urges viewers to take notice of how their actions are affecting the environment and warns of what might happen if they don’t.
3) Bambi — The classic animated film from 1942 tells the story of a young deer and his friends who live in a forest threatened by hunters. When Bambi is still a fawn, his mother is killed by one of those hunters, and he must grow up without her. Bambi and his friends get older and he falls in love with another deer, Faline. Everything is peachy until the next day, when the forest goes up in flames and Faline is attacked by hunting dogs. Bambi is able to save her, and the couple eventually escapes to an island in a lake, where they live (at least we expect) happily ever after. The scene where Bambi’s mom dies would make even the most hardened hunter think about setting down his gun.
4) Over the Hedge When the forest animals, the main characters in Over the Hedge (2006), wake up from hibernation, they realize that half of their forest has been destroyed and replaced by a suburban neighborhood hidden behind a giant hedge. The animals, especially raccoon RJ, who is paying off a debt to an angry black bear, try to survive by stealing food from the humans who live on the other side of the hedge. The plot revolves more around the interactions among the animals than an environmental message, but some pointed comments are unmistakably meaningful: “That is an SUV,” says RJ in the trailer. “It’s so big!” respond the animals. “How many humans fit in there?” RJ’s reply is priceless: “Usually…one.”
5) Hoot — Based on a Carl Hiaasen novel, this 2006 film portrays the adventure of three middle-school students who try to protect a rare breed of endangered owls. The main character, Roy, just moved to Florida from Montana, and quickly makes friends with Beatrice and her truant stepbrother, “Mullet Fingers.” The three set out to derail a greedy CEO in his construction of a pancake restaurant on the vacant lot where the rare owls live. Not exactly an award-wining movie, but definitely one that encourages kids to think about the relationship between humans, development and wildlife.
6) Star Trek IV: The Voyage Home — Whether this 1986 film can be considered a movie for kids is debatable, but its environmental undertones are clear. It’s the year 2286, and a strange probe is approaching Earth, sending out signals that Spock determines match the calls of the extinct humpback whale. The probe is wreaking havoc on Earth, so the crew of the USS Enterprise decides to go back in time to 1986, where they find two whales in a San Francisco aquarium. A curator there explains to the crew members why the whales are endangered. They take the whales back to the future with them and release them in the San Francisco Bay, where the giant mammals answer the probe’s signal and stop the destruction. Logical? Maybe not. But with an environmental message? Most definitely.
7) Free Willy — Another movie with whales and an environmental message, Free Willy was a hit in 1993. It features a young boy who befriends a recently captured orca whale in a local aquarium/amusement park. The boy, Jesse, and the whale, Willy, bond, but Willy is in danger because he doesn’t perform tricks well and therefore doesn’t earn much money for the park. The park owner and his cronies threaten to kill Willy, so Jesse decides to release the whale into the wild. There’s no mistaking the villains in this movie—the park owner, who exploits animals, and the whalers who capture Willy—or the message that wild animals are better off left alone.
8) Disneynature’s Oceans — Though a bit more subtle than some of the other films on this list, Oceans still makes an impact. A documentary released on Earth Day in 2010, the film explores the underwater world that covers three-quarters of our planet. While it spends much of its time depicting the weird, wonderful and beautiful life forms that the oceans have to offer, the documentary doesn’t miss its chance to show the negative effects human actions can have on wildlife and urge viewers to respect nature.
9) Avatar – Again, it’s debatable whether this is a kids’ movie, but it’s clearly a film with environmental themes. A paraplegic soldier travels to the planet of Pandora, where he, in the form of his avatar, integrates with the indigenous Na’vi people. He is supposed to help conquer the foreign land, but soon finds himself siding with the Na’vi. There are many themes in this 2009 film, but among them are a respect for the environment (demonstrated by the graceful Na’vi), our ultimate reliance on nature and the destructive nature of humans and how it affects the planet.
10) Happy Feet — The main message of this 2006 Disney movie is that it’s okay to be different, but environmental themes work their way in as well. The film focuses on a young penguin, Mumble, with a talent for tap dancing—something none of the other penguins can do. It follows his adventures and quest for acceptance throughout the plot, but the environmental aspect shows up when Mumble is blamed for the scarcity of fish in the ocean, a nod to overfishing. In addition, one of Mumble’s friends wears a set of plastic six-pack rings around his neck like jewelry, only to later be choked by the piece of trash. Happy Feet is an example of the environment showing up in movies that are not directly about the environment.
Giving films a green theme is clearly a trend in cinema lately. What other environment-focused kids’ movies did we miss?