Science of Disney · Uncategorized

Science of Disney: How Ants Find Food

Foraging for food is an essential premise of a Bug’s Life – the ants have to collect enough food to feed the grasshoppers and get food for themselves. The movie got some parts of this process right – ants do often travel in a line to get from a food source to their nest – but the process is much more impressive than just following the leader.

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From Pixar’s A Bug’s Life

To harvest food, ants use a combination of several different sensory systems – smell, sight, and touch.

Ants have four to five times more odor receptors than most other insects. It is unclear whether all 400 ant genes for different olfactory receptors are actually expressed but this allows ants to distinguish several different scents. For comparison, humans have 1000 genes for different olfactory receptors (proteins to detect chemicals) but only 350 to 400 of them are actually found in cells. Ants use these odor receptors to sense the presence of food up to several meters away depending on the species, but more importantly, they use these odor receptors to detect pheromones.

Pheromones are chemicals secreted by ants (and several other insects and animals) for a variety of purposes. Whereas many mammals secrete pheromones to mark their territory, ants secrete pheromones to mark a trail towards food (as well as to recognize each other, attract mates, and signal alarms such as when an ant dies). Other ants will detect these chemicals with their own antennae and follow the trail towards food and back towards their nest.

Detecting pheromones is important for the emergent process of how ants form lines – it isn’t because they are watching other ants with their eyes or because they are programmed to follow each other. Ants can more easily detect pheromones along trails that have the strongest pheromone scent. Ants who travel on shorter trail between the nest and food can make more trips in an hour than ants traveling along longer trails, which means the shorter trails will have more pheromones deposited due to the path being more heavily traveled.

This is kind of like how humans try to find information online. If a page is particularly useful, it will get more page visits. With more visits to a page, a website’s ranking in Google searches increases which makes it easier for additional people to find the information they need – this shortens the path from search to result because this is the path that other people have traveled.

How do ants get back home?

In addition to leaving pheromone paths, ants use sight and touch to get back home as well. These senses come in handy especially when an ant has traveled a far distance and their pheromone scent has dissipated and is more difficult to detect. When an ant is searching for a new food source, they store images of their path so that they can identify landmarks on their return journey.

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From Pixar’s A Bug’s Life

Ants also know where there home is based on the sun’s position. Researchers were able to help ants that were traveling backwards, pulling a cookie crumb that was too big to carry moving forwards, find their way back home by adjusting where light was coming from. This suggests that ants have an understanding of their general position in their surroundings.

Additionally, ants are believed to be able to count their steps and keep track of changes in direction on their path when searching for food. Researchers have tried several ways of disrupting this ability with little success, which has promising applications for programming robots to navigate dangerous areas.

Furthermore, there is research that suggests that ants may be able to detect magnetic fields and vibrations because placing magnets near nests serves as an identifier for ants: they sometimes search for their nest based on this cue.

Can ants sense when it is going to rain?

The ants in the colony in a Bug’s Life had to collect enough food before the rainy season. This and the frequent observation that ants leave their nests around the time of rainstorms suggests that ants have some way of knowing when it is going to rain, but is this based in any scientific fact?

Currently, there is no definitive evidence that ants can detect changes in the weather, but they have other interesting behaviors. Most ant species actively forage at times of day and seasons specific to their species. Most of these behaviors are due to ants’ abilities to detect temperature and atmospheric moisture changes. Because ants do not have blood but instead free floating fluid called hemolymph, they have to regulate their body temperature based on external factors. Small changes in moisture affect ants’ abilities to bend their joints, so they might remember that this correlates with rainstorms.

According to Dr. Kirsti Abbott, ants may be able to detect changes in air pressure through their breathing mechanism – holes in their exoskeleton called spiracles. Because drops in air pressure frequently precede rainstorms, ants may learn this association as well.

References

https://www.sciencedaily.com/releases/2006/10/061018094651.htm

https://www.popsci.com/ants-find-way-walk-backwards-navigation

https://www.sciencedirect.com/science/article/pii/S0960982212009323

https://www.sciencedaily.com/releases/2014/05/140526182749.htm

https://news.vanderbilt.edu/2012/09/10/ants-have-an-exceptionally-high-def-sense-of-smell/

Disney Tips · Disney Trips · Science of Disney · Uncategorized

Science of Disney: Elephants and Bees

One of earth’s biggest creatures is being saved by insects.

As part of Animal Kingdom’s 20th Anniversary celebration, I attended a Tiffins Talk in which I enjoyed a four-course meal inspired by and specially prepared to accompany a presentation from a Disney scientist about their conservation efforts. During this talk, Dr. Joseph Soltis gave a very engaging talk about how he, his colleague, Dr. Lucy King, and the Disney Wildlife Conservation Fund are helping to save elephants with honeybees.

What’s the problem?

Elephants are impressive creatures but the species has faced constant treats from humans. Even with reductions in the ivory trade, humans and elephants still come into conflict, especially in countries like Kenya, Mozambique, Tanzania, Uganda, and Sri Lanka. One of the biggest causes of human-elephant conflict is crop raiding, which is when elephants wander onto farmland in search of food. Because they are so big (and have big stomachs), the farms are decimated and the farmers lose both their own food and their source of income. As a result, farmers sometimes kill or hurt elephants to prevent further damage and protect themselves.

What could be done?

If only there were some way to keep elephants out of farms. Standard or even heavy-duty fences won’t work because they are expensive to put up and maintain and elephants might knock them over anyways. By putting collars on elephants to track their location, farmers can be alerted any time elephants cross a virtual fence line and then scare the elephants away enough times until they are conditioned to not even approach a farm. Again, these collars are expensive and still can result in more conflict than is necessary. Other techniques, like the ones outlined in the Save the Elephants Human-Elephant Conflict toolbox, can also help to some degree. Fortunately, some observations from locals led to some scientific discoveries that have significantly reduced human-elephant conflict.

Elephants often retrieve food from trees – whether it is the fruit or the leaves. But one Kenyan guide that was leading Dr. Soltis and Dr. King, shared that he had noticed that elephants never retrieve food from trees with beehives. Elephants in Zimbabwe are also known to forge entirely new paths through jungles to avoid trees with beehives. This is quite curious because elephants have relatively small areas that are sensitive enough to potential bee stings (inside of the trunk, eyes, and ears) and it does not make a lot of sense that such large creatures might systematically avoid bees if they cannot do much damage.

Studies about Elephants’ Fear of Bees

So the researchers set out to see not whether elephants are harmed by bees but instead to study whether elephants are afraid of bees. Rather than using actual bees, researchers played recorded bee sounds using giant speakers hidden in foliage near elephant meeting spots. And then they watched to see what the elephants did. When the bee sound was played, all but one elephant family ran away in under 90 seconds; half of the families ran away in under 10 seconds. In contrast, when just white noise was played (because it is always a good science to have a control condition), all of the elephant families stayed in the area for about four full minutes or casually walked away. This suggested that elephants have learned about and/or remember their personal experience with bees and that bees do not have a pleasant association. Similar behaviors were observed in elephants in Sri Lanka in response to the sounds of Asian honeybees (King, Pardo, Weerathunga, Kumara, Jayasena, Soltis, & de Silva, 2018).

Communicating about Bees

In addition to running away in response to hearing bee sounds, elephants produced rumble calls, shook their heads, and tried to throw dust on themselves. To better understand this behavior, Dr. Soltis, who is an expert in elephant rumbles and has conducted several studies with the elephants at Disney’s Animal Kingdom, headed up a follow-up study. He wanted to know specifically if elephants’ rumble calls for bees were actually being used in similar ways as to how humans screaming scream “Spider!” or “Mouse!” when they are fearful and want to alert others.

To answer this question, the research team used a similar protocol as with the recordings of bee sounds except in this case, the speakers played recordings of the rumbles that the elephants had made in response to bee sounds. Elephant families moved away from the speakers much more often and moved farther when the rumble calls for bees were played than when just white noise or when modified rumble calls were played. Additionally, families moved faster and shook their heads more when the rumble calls for bees were played than for the other two control sounds. Dusting behavior was not observed to be significantly different across conditions. It seemed that indeed, elephants were communicating their identification of the presence of bees to others so that they all could avoid being stung.

Conservation Implications

As a result of this discovery, Dr. Soltis, Dr. King and their partners in Kenya wanted to put this research to use. They could have given the farmers some large, expensive speakers to play bee sounds but they did something even better. The research team started testing the effectiveness of bee fences for reducing crop raiding. To set up a bee fence, beehives are set up at the perimeter of farms and connected with wire. Any time an elephant hits the wire, the hives are disturbed and the bees produce swarming sounds. These are the same sounds that elephants are afraid of so the elephant will run away from the farm. The early tests were successful and crop raiding has significantly declined for farms with beehive fences. Not only do the beehive fences protect the farms and thus allow the farmers to keep their main source of income, the honey from the beehives can also be harvested and sold for additional revenue.

Unfortunately, you cannot buy this elephant honey directly outside of Kenya, but you can donate to Save the Elephants using the links here to support this program and prevent further human-elephant conflict.

What would you want to research in partnership with Disney? Comment below!

References

King, Soltis, Douglas-Hamilton, Savage & Vollrath (2010)

Lucy King’s Dissertation (2010)

King, Douglas-Hamilton, & Vollrath (2007)

King, Lawrence & Douglas-Hamilton (2009) Beehive fences deter elephants

King, Douglas-Hamilton, & Vollrath (2011) Beehive fences effective deterrents

Soltis, King, Douglas-Hamilton, Vollrath & Savage (2014) Different Elephant Alarm Calls for Humans and Bees

King, Pardo, Weerathunga, Kumara, Jayasena, Soltis, & de Silva, 2018

Save the Elephants – Elephants and Bees Project

Save the Elephants – Geo-Fencing

Science of Disney · Uncategorized

Science of Disney: Buzz’s Spacesuit

“Buzz Lightyear to Star Command, Buzz Lightyear to Star Command”

Named after Buzz Aldrin, one of the first men on the moon, Buzz Lightyear had a pretty spiffy spacesuit complete with a wings, a laser shooter, and a simple voice-recorder that could transmit his adventures to the intergalactic headquarters. According to John Lasseter (former chief creative officer at Pixar), the design of Buzz’s suit was inspired by the suits worn on the Apollo missions. How does Buzz Lightyear’s spacesuit compare to what astronauts really wear? Let’s find out.

 

 

Outside the spaceship

Most importantly, space suits – called EMUs for extravehicular mobility units – need to provide the proper air pressure, oxygen and temperature for astronauts to breathe and otherwise function in space. Without proper air pressure, the water in the astronaut’s body could boil at body temperature (37˚ celsius) instead of the much higher temperatures (100˚C) at sea level. To provide livable conditions, many EMUs fill with air (primarily oxygen), causing astronauts to function kind of like they are inside a human-shaped balloon animal.

Secondly, these suits also need to facilitate movement to move about and fix equipment, whether on the moon, the International Space Station, or near and distant planets. Increasing the ease of moving with minimal effort requires trade-offs with air pressure regulation and thus increases and the risk of sickness for the astronauts due to imbalances between oxygen and nitrogen. Other concerns are protecting against the elements in space – including radiation and micrometeorites traveling at very high speeds that can potentially abrade or otherwise damage the layers that compose EMUs.

Suits that are intended for use in 2018 and beyond have received a few design upgrades over early spacesuits. They have been designed with more flexible joint areas and zippers for greater mobility and comfort, vents to allow the release of moisture so that astronauts can keep cool, and gloves capable of operating touch-screens with finer dexterity.

 

Inside the spaceship

Inside the ship, astronauts need to be able to move about, eat, sleep and go to the bathroom. They usually are not as concerned about facilitating breathing because the inside of the space ship is carefully controlled to allow life-preserving conditions, but modern suits still are capable of serving these functions in case of emergency. As a result, spacesuits for intravehicular activity (IVA) have fewer layers, and are thus lighter-weight, more flexible, and easier to don and doff (contraction of do off).

Compared to Buzz

Appearance

The suit that we always see Buzz wearing is most similar to an EMU, and is designed to be similar to the Apollo spacesuit. Keeping the consistency of the white color of the suit helps to deflect solar radiation and stand out against the black of space; whereas Buzz has purple and green accents as symbols of Star Command, the red stripe accents on Apollo suits helped to differentiate among astronauts.

Basic Features

His suit is a combination of hard upper pieces and soft lower pieces, much like Apollo suits. Also like the Apollo suits, Buzz’s suit appears to have a backpack but whether it houses the life support system (including oxygen tanks and carbon dioxide removal system, water cooling system, two-way radio and batteries for electricity) is not apparent. Buzz’s helmet is globular like the Apollo suits but more closely resembles more modern IVA suits because it is clear rather than reflective. Because it is clear, Buzz’s helmet is likely incapable of deflecting the harmful rays of sunlight that are more intense in space than when filtered through Earth’s atmosphere and thus suited only to intravehicular activity.

Wings

Astronauts don’t have wings because they don’t have to fly without a spacecraft. Plus, the minimal gravity on the moon and lack of gravity away from the surface of planets makes wings a bit useless. Wings that flap like a bird’s would still be useful in controlling movement inside a space station but wings that serve just to allow lift and gliding (like those on Buzz’s suit) wouldn’t be very helpful.

Outside the spaceship where there are essentially no air molecules like in Earth’s atmosphere, wings would be even more useless. Modern astronauts use a separate unit that attaches to their spacesuit and is equipped with multiple thrusters to control their movement when outside the spacecraft.

The lack of air molecules in space is why planes can’t go to space and why we need spaceships with powerful thrusters and with parts capable of being detached to create momentum to move the ship instead of relying on lift and drag. The wings on a space shuttle are only for guiding upon exit and re-entry back into the Earth’s atmosphere.

 

Retractable helmet

Although Buzz’s retractable helmet is pretty cool, it likely isn’t feasible for real astronauts. The seal between the helmet and the suit is one of the most crucial aspects ensuring astronauts’ survival. The glass part of the helmet needs to be one piece of extremely strong material to prevent gaps that would throw off the air pressure and temperature regulation, rather than the typical layering of sections of material in many retractable items (like lightsabers or straws). If there is room in the astronaut’s helmet for the piece of coated Plexiglass to move back and forth, there would have to be a fail-proof mechanism for ensuring that the seal between the glass and the rest of the helmet is secure. This mechanism would have to operate without vacuum sealing because the air pressure in the head cavity needs to be similar to the air pressure surrounding the rest of the body inside the suit.

Cross-space communicator and log recorder

Most of the communication equipment is housed in an astronaut’s helmet when engaged in activity outside the spacecraft; when inside the spacecraft, astronauts more often wear headsets with earphones and microphones like we see in everyday purposes on Earth. Buzz is more often seen communicating via a wrist microphone which is inefficient because astronauts are often using their hands for other tasks, like holding onto handles inside and outside the spacecraft to control their movement. It is much more important for this visible real estate on astronauts’ wrists to have information about the internal pressure of their suit and their availability of oxygen than for communication (or a mirror to be able to read these stats located on the chest panel).

Wrist laser

Again, wrist real estate is extremely valuable for astronauts. Having a laser located there might not be the best option and modern astronauts rarely have use for a laser in the ways that Buzz does (usually for threatening or attacking enemies). The closest thing that astronauts have to a laser weapon is probably welders for when they are fixing their space station or ships. However, lasers are being used in other ways in space such as measuring distance between objects in orbit, detecting substances, cleaning up space debris, and transmitting more information more rapidly. Even still, the entire beam of the laser from origin to destination point isn’t visible to the human eye because there aren’t sufficient particles in space to reflect and make visible the light of the laser beam.

Suits of the Future

Dava Newman and her colleagues at MIT and beyond (including a former astronaut!) are working to design a new spacesuit called the BioSuit that is skintight and will make it easier for astronauts to move while still providing the necessary air pressure, temperature and oxygen. New materials and a carefully calculated exoskeleton are supposed to exert enough pressure on the astronaut’s body for all of the body’s cells to maintain functionality. They are also working on a different type of junction between the helmet and suit so that astronauts can turn their necks and look over their shoulders. Although they are still a ways off from having a space-proof suit, the research also has many potential biomedical applications as well, such as helping monitor and correct abnormal motor movement in stroke and cerebral palsy patients.

As we learn more about the effects of wearing spacesuits and living in zero gravity, maybe we can eventually go beyond to the special features seen on Buzz’s suit, or even the grappling hooks and magnets that come with the new and improved utility belt in Toy Story 2. But first, infinitely more research needs to be done on safety and health of astronauts before we can envision this or the emergence of something like Star Command.

Citations

Dava Newman’s BioSuit

Spacesuits for 2018 and Beyond

3D Printing and Suits for Mars

SkinSuit Prevents Muscle and Spine Problems from Zero Gravity

Wikipedia page on the Apollo spacesuits

Wikipedia page on skin-tight suits

Trade-offs of mobility and safe air pressure in spacesuits

NASA Spacesuit Features

WIRED piece on the evolution of spacesuits

Air & Space Magazine evolution of spacesuits

NASA laser usage in orbit

Princess Life · Science of Disney · Uncategorized

Science of Disney: Sleeping Death

Hopefully none of the super cool science information below puts you to sleep!

So what caused Sleeping Beauty’s coma or death-like slumber?

Including Juliet imbibing a sleeping draught or Snow White eating a poisoned apple , fictional characters have been put into death-like states (or faked their own deaths) in myriad ways. So what likely caused Sleeping Beauty’s death-like state? How might pricking a finger have led to the princess losing consciousness? And could true love’s kiss really awaken someone from such a state? Maybe the magical secret is the too-coincidental-to-be-overlooked common thread of roses (that famous Shakespearean line, the color of Snow White’s lips, Sleeping Beauty’s secret identity), maybe it’s science or maybe it’s both.

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According to The Film Theorists, plants may be the culprit behind these medieval motionless maladies. But unfortunately the suggested plants refute my rose hypothesis: none of the likely suspects are in the Rosaceae (rose) family. First, atropa belladonna, a poisonous plant commonly found in medieval Germany (in which the authors of Sleeping Beauty and Snow White, the Brothers Grimm, lived) might be what caused these princesses’ death-like states. In addition to being poisonous when ingested, this plant was often used to make poisonous arrows. And arrows are pretty similar to spindles, so it is possible that the spindle with which Sleeping Beauty pricked her finger was also coated in the same belladonna poison.

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Atropa belladonna is actually a combination of the name for a Greek Fate and the Italian word meaning beautiful woman

Atropa belladonna’s deathly powers can be attributed to a chemical makeup that is high in alkaloids. These alkaloids work by blocking receptors in the nervous system for a chemical called acetylcholine, like blocking all of the doors to the elevators and stairwells to prevent you (the acetylcholine in this analogy) from getting to the right floor of a building (neurons that control movement of muscles that regulate breathing and neurons that regulate heartbeat the heart). One of the main side effects of the specific alkaloid in atropa belladonna is to speed up the heartbeat, eventually leading to heart attack. Although the mechanism of delivery for this poison seemed good, it is more likely that Sleeping Beauty’s heartrate slowed down to a restful, death-like state rather than speeding up.

 

Another hypothesis that I think is more likely is that Sleeping Beauty went into a hypoglycemic diabetic coma after pricking her finger on a spindle that may have been coated in insulin.These comas are caused by the concentration of sugar in blood reaching too low of levels and the hormone insulin reduces the amount of sugar in the blood. While it is highly unlikely that Maleficent was able to isolate insulin into a substance in medieval times, the spindle might not have been necessary at all; the sum of experiences that Sleeping Beauty experienced leading up to the finger-pricking moment may have also caused the coma.  The clues are all there – she didn’t have a chance to eat her birthday dinner or cake and then had to walk briskly to the castle which would’ve depleted her body’s sugar reserves. Hypoglycemic diabetic comas have symptoms such as fatigue, weakness and light-headedness as well as shallow breathing which could all be some of the things that we see Sleeping Beauty experiencing in the Disney film. Furthermore, it is actually feasible that this state could have been cured by true love’s kiss. If Prince Philip’s lips and tongue were coated in several grams of glucose, this could have been enough to rebalance Sleeping Beauty’s blood sugar levels by allowing her to digest the glucose. All in favor of renaming Prince Philip to Prince Sugarlip from now on, say aye!

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Lastly, the third hypothesis is that Sleeping Beauty suffered head trauma and a subsequent coma after pricking her finger. But, Sarah, you might say, that’s silly; pricking a finger has nothing to do with head injury! And this is where my personal experience with something called a vasovagal syncope allows me to undermine that assumption. Vasovagal syncope causes someone to lose consciousness, often for only a few seconds or minutes, because some sort of external stimulus causes nerve signals (the same ones affected by atropa belladonna chemicals) to dramatically decrease heart rate, which lowers blood pressure, which prevents more blood and more oxygen to reach the brain.

My handful of vasovagal response experiences have been caused by triggers of descriptions pain or anything to do with breaking bones but several other people are triggered by needles or blood. You know what else is sharp like a needle and can draw blood? A spindle! So Sleeping Beauty could have lost consciousness and fell to the floor due to a vasovagal response to pricking her finger. In the process, she could have hit her head hard enough on the cobblestones of the tower room to be put into a coma. Unfortunately, there is still no scientific evidence showing that a kiss has the ability to awaken anyone from coma.

Thanks for reading!

Which do you think is the most plausible scientific explanation?

Check out my Instagram posts @thephdprincess for more science related to Sleeping Beauty! I just had too much information to fit into this one post!

Citations

Diabetic Comas

Vasovagal syncope

Science of Disney · Uncategorized

Science of Disney: Drop Rides

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Two of the most jaw-dropping Disney attractions – the Tower of Terror and Guardians of the Galaxy: Mission Breakout! – employ some plussed up elevators for an exciting and sometimes nauseating ride experience. Dropping 13 stories at a speed faster than freefall requires some pretty interesting science!

The Ride Vehicle

Most of the sources I consulted say that the Guardians of the Galaxy gantry lift or Tower of Terror elevator is an example of a simple traction elevator. Traction elevators operate as pulley systems. For Disney’s versions, each elevator shaft has two “drums” or wheels with cables running over them attached to motors located on the top floor. The cables from one drum are attached to the elevator vehicle or “cab”; the cables from the other drum are attached to a counterweight. Another set of cables is attached to to the bottom of the cab, goes around another pulley wheel at the bottom of the shaft and is attached to the bottom of the elevator cab.

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This design is pretty clever because it relies on a few laws of physics to reduce the amount of electricity required to run it! If we want to move the elevator up, we have to do work (a formal concept in physics, not like the chores that Cinderella did every day) in order to increase its potential energy. The physics concept of work is the amount of force applied across some distance: if we want to move the elevator up 13 stories (or about 130 feet) we have to put in a lot more work than if we wanted to move it 13 inches. The force that is applied across that 13 stories or 13 inches would have to be equal and opposite to the weight of the cab full of people.

The counterweight helps reduce the amount of force and thus the amount of work that the motors have to generate because gravity pulling down on the counterweight does some of the work for the motor. Gravity pulling down on the counterweight causes a force on the cables that is in the same direction as the elevator cab going up. But usually this counterweight doesn’t have as much mass and therefore not as much weight as the elevator, so the motor has to do the last bit of work to pull up on the cables attached to the cab.

For the cab to be “dropped” down the shaft, gravity could do all the work, but that wasn’t enough for Disney Imagineers. For the fall, an engine generates up to 1200 volts of electricity (10 times the electricity in a standard American outlet) to spin the motor in the opposite direction and pull down on the elevator. Combining this additional pull from the motor-driven cables accelerates the cab at a rate faster than gravity which makes for a shriek-worthy sensation.

 

The Experience

In real life, many people are scared of the possibility of an elevator plummeting to the ground, no matter how matter whether its 13 stories or just 3. But it is much more likely to wind up stuck in an elevator (sorry for the claustrophobes out there!) than it is to have an elevator crash all the way to the ground because there are elevators are equipped with so many back-up systems to prevent them from falling. Elevators only need one functioning cable to operate normally but they usually have at least three (each Disney ride elevator has five). Even if all of the cables were to be non-functional, which is highly unlikely due to regular maintenance checks on the wear and tear of the cables, each elevator has two braking systems which are also examined routinely. One braking system works to stop the motor from spinning and the other stops the elevator from falling by extending a brake into the guide rails of the shaft.

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Even going into the ride knowing that the ride is totally safe, the feeling of freefall can be quite frightening. Freefall is the name for when the only force acting on an object (for example, 21 human bodies in a metal box) is the acceleration due to gravity (32.2 feet per second per second) but we know from our exploration above, that the elevator falls even faster than freefall due to the motor putting in work. The elevators on Guardians of the Galaxy and Tower of Terror reach speeds of 39 miles per hour!

I have to save the science behind the magic of the Fifth Dimension portion of Tower of Terror at Disney’s Hollywood Studios for another day, but comment below with which version of this terrifying tower ride is your favorite!

Citations

Short & Sweet Stats

Translation of a German Film about Paris’s Tower Construction

More on Elevators

More on Tower of Terror Motors

Explore more Physics!

How Counterweight Works Mathematically

More Fun

Tower of Terror Simulation Game

Science of Disney · Uncategorized

Science of Disney: Smellitizers

From the sweet wafting of vanilla on Main Street, USA to the slow burning of wood in Spaceship Earth and the barrage of ocean breeze and orange groves in the various iterations of Soarin, Disney employs some relatively simple technology to enhance the sensory experience of their park and make your memories that much stronger.

How do Disney’s scent machines work?

Disney’s scent machines, often referred to as smellitizers or smellitzers, are used throughout the parks in various attractions, including but not limited to Soarin’, Spaceship Earth, Living with the Land, Stitch’s Great Escape, Journey into Imagination, and Muppets Vision 3D to accompany sights and sounds and make the attractions feel much more realistic.

These smellitizers are descendants of Smell-O-Vision which was used in movie theaters in the 1950s but quickly declined in popularity. Smell-O-Vision in theaters failed primarily because the fans used to dissipate the scents were loud and the scents took too long to dissipate to the audience so that they were not synced properly with the film which both detracted from the movie-watching experience.

Imagine not smelling the dirt from Mt. Kilimanjaro until the Paris scene – doesn’t really make you feel like you are transported to either locale, does it? What’s so special about Disney’s technology is that the smells are timed precisely, released relatively discreetly and directly, dissipate quickly and can be used repeatedly for around 80 to 100 showings a day per theater.

Put simply, Disney’s machines involve programming a container of a scented substance to be positioned in front of a fan and turning on the fan to blow air across the substance and toward the audience. This process works because of how chemicals become airborne and how we smell, which I explain below.

What causes smell?

We can only smell substances that are sufficiently volatile. Volatility doesn’t mean that the substances are evil or mean like Scar or Maleficent but rather, a volatile substance has a tendency to vaporize, or turn into a gaseous form. We are only able to smell things when the molecules that make them up are in gaseous form because only gases can reach the space in our skull where we detect smells. But how do substances that are not gases to begin with transform into gases?

Typically, substances transition from liquid into gas form, like when we boil liquid water and it turns into water vapor. Similarly, scented candles distribute scent by heating solid wax first into a liquid and then into a gas. But liquids are difficult to control in machinery, thus smellitizers are not likely to use substances in liquid form.

Because we are still seemingly able to smell the scents of things like candles, soaps, and perfumes even when they are in seemingly solid form, is there another way that smellitizers could achieve their desired effect? Yes! They could either rely on containers of chemicals in gaseous form already or on a process of transforming a solid into a gas called sublimation, which is the same process at work in solid air fresheners.

Sublimation requires very special conditions depending on the material in order for the molecules in a solid to have enough energy to become a gas. Heating a solid air freshener is one way to cause sublimation and distribute scent but I think it is unlikely that Disney uses nearly constant heat in all of its smellitizers if it can be avoided because of the high cost of supplying enough energy for such a process. Furthermore, regular life experience seems to indicate that solid air fresheners work pretty effectively even when not in a heated location. Thus, alternative materials or conditions need to be used to make a solid substance in a smellitizer smell.

The most likely explanation is that blowing cool air over the scented substance (typically composed of volatile organic compounds) with a fan lowers the air pressure above the scented substance by blowing away the molecules that were present before. The same process is at work when wind blowing over a puddle causes the puddle to evaporate more quickly. With fewer molecules present above the scented substance or puddle, more molecules can escape into the air. More molecules turning into gas form results in a higher likelihood that we will detect a smell.

How do we smell?

Chemicals from smell-producing objects travel through the air, into our nostrils (or through our mouth and to the back our throat), through our nasal cavity until they reach a section of the nasal cavity called the olfactory epithelium. The olfactory epithelium is a membrane covered in mucus that traps the chemicals for smell and is littered with 40 million olfactory neurons. Each of these neurons has special proteins in their membranes which function like locks that are only opened by the proper smell molecule key.

After the molecule unlocks all the receptors that it can, the neurons with those receptors activate and send a signal to a different part of the sensory nervous system called the olfactory bulb, which is just a bundle of neurons. In addition to sending the signal from the olfactory bulb straight to the olfactory cortex (where higher-order processing occurs), the signal is sent to both the amygdala, which is responsible for emotions, and the hippocampus, which is integral for memory formation.

 

Why is smell so powerful for triggering memories and emotions?

The several neurons activated by a smell’s molecules are usually arranged in a particular spatial pattern in the olfactory bulb that is gradually (through repetition) associated with the object that caused the smell. This recognition is how a memory for a smell is formed, just like the activation patterns associated with the color red in the visual cortex or our friend’s voice in the auditory cortex are paired together over time. Because we have more types of receptors for smells (at least 350!) than we do for sight, our memories for smells can be much more specific and also require less complicated integration of sensory information. This specificity may be one of the reasons why we can recall a more specific set of memories from a smell than from just an image (such as a photo of a perfume bottle or the word “rose” instead of the smell associated with each).

Additionally, there are fewer steps involved in the pattern recognition of smells (through the olfactory bulb then to the cortex) than the pattern recognition of sights or sounds (which must first go through a traffic control center called the thalamus). The sensory pathways for smell are much more integrated with the amygdala and hippocampus than other sensory pathways, which likely served our ancestors well in their survival: having a better memory for smells of predators and dangerous foods would prevent death.

Furthermore, smell memories are some of the best-preserved over time. If the first time a memory for a scent is formed occurs during childhood, positive emotions associated with nostalgia can make that memory even more powerful. This may explain why the faintest smell of a churro can bring me back to walking along the Rivers of America in New Orleans Square and why I burst into tears when the Disneyland 60th Anniversary fireworks were accompanied by gingerbread scented “snow” that reminded me of baking gingersnaps with my grandmother.

What scent (Disney or non-Disney) is the most powerful for you? For me, it’s the smell of oranges from Soarin’ and the smell of fresh-cut grass from home.

 

Citations

Patent for Soarin’ Ride System

Patent for Soarin’ Smellitizer

Illustrated Video of Smell by Ted-ED and Rose Eveleth

History of scent-emitting technology

Linda Buck’s Nobel Prize Acceptance Speech Transcript for Smell Receptors

Arshamian A, Iannilli E, Gerber JC, Willander J, Persson J, Seo H-S, Hummel T, & Larsson M. The functional neuroanatomy of odor evoked autobiographical memories cued by odors and words. Neuropsychologia 51 (2013), 123-131.

Where to Buy Disney Scents (not sponsored)

Walter and Rosie Candle Co.

WED Way Candle Company

Science of Disney · Uncategorized

Science of Disney: California Screamin’ / Incredicoaster Launch

Tantalizing trills of a triangle, a cadence of carnival bells, then a countdown – 5…4…3…2…1! – and the screaming begins.

California Screamin’ at Disney’s California Adventure closed January 8th, 2018 and was re-themed with an Incredibles overlay to become the Incredicoaster. Today, I’ll explain some science concepts integral to the launch of this awesome ride.

How does this coaster’ launch you from 0 to 55 miles per hour in under 5 seconds? Most roller coasters rely on a motor and chains to pull the train up a lift hill (the initial tallest hill) to provide enough potential energy to make it all the way around the track, but The Incredicoaster manages to send a train around the longest looping roller coaster track (6072 feet!) without a mechanical lift hill. Instead, this roller coaster uses a linear induction motor. How does a linear induction motor work? In a few words, with high-powered electromagnets and electromagnetic induction. To explain further, let’s review some basic physics.

How do magnets and electricity work together?

Charges (like electrons) moving together in one direction, like in a wire conducting electricity (literally the movement of electrons) create an electromagnetic field around the flow of charges. When two magnets or two electricity carrying wires creating electromagnetic fields are brought close to each other, the electromagnetic fields between the two electromagnetic objects combine depending on the direction. If the fields are going in the same direction, the force created by the field is stronger between them; this occurs when magnets of the same polarity come into proximity with one another. When the two fields are going in opposite directions, a weaker force is created like when you combine a negative number (-5) and a positive number (7) to get a number that has a smaller absolute value (2) than either original number; this occurs when magnets of opposite polarity come into proximity with one another.

Like in other domains of physics and chemistry, an equilibrium, in this case of forces, is the most stable and thus desirable state. In order to get rid of the stronger or weaker forces, the magnets want to move to a state of equilibrium. When magnets of the same polarity create a stronger force between them, moving away from or repelling each other leads to an equilibrium state.

How does the Incredicoaster use electromagnetism?

The launch system for the Incredicoaster employs this idea of movement as a result of repelling magnets to move the train forward. There are several slots in the track of Incredicoaster that have electromagnets (unclear whether these are coils of wire or metal plates) with current flowing in one of three states (inward direction, outward direction, or not flowing at all) regulated by switching on and off a connected battery at different times. This battery is controlled such that each small section has an electromagnetic field going in a different direction from the section adjacent to it.

After the train is in position on the launch section of the track, the electromagnetic fields at the beginning of the launch section are turned on by “a 25-megawatt transformer [feeding] a 5,000 horsepower variable frequency drive” in a “100-yard-long room beneath the ride” according to this New York Times article. The magnetization of the track causes movement of electrons in a metal blade attached to the bottom of the train so that the electrons align with the electromagnetic field of the track. This movement within the metal blade creates electromagnetic fields within the metal blade called eddy currents. The electromagnetic fields of these eddy currents interact with the electromagnetic fields of the track to create repulsions and move the train forward. This process continues as the current in each section of track cycles through each possible state (in, out, or off). The wheels of the coaster keep it guided along the track as the train picks up speed with each subsequent repulsion and the riders shriek with delight (or fear).

The same process is at work when the coaster needs to pick up speed over the highest hill after the launch as well as any time the coaster needs to brake (although in this case, the electromagnetic fields work to push the coaster in the opposite direction, effectively slowing it down).

Can you guess which other Disney rides use this same technology?

 

 

Helpful Videos

 

Disney Tips · Disney Trips · Listicles · Science of Disney · Uncategorized

Top 5 Educational Experiences at Epcot

Although Walt Disney’s original vision for Epcot is far from realized, the spirit of showcasing technological innovations and providing memorable and educational experiences for guests lives on!

  1. Living with the Land – This ride is very long but really interesting. I never thought I would care about agriculture but finding out that Disney produces as much of its produce on-site as possible was really impressive! Seeing real scientists at work monitoring the plants and animals and their growing conditions in the most magical place on earth is bound to be inspiring for aspiring scientists, young and old. They offer a Behind the Seeds tour as well if you want more information about the work going on behind the scenes to feed hundreds of thousands of guests each day.
  2. The Seas Pavilion – Despite growing up a short drive from the Monterey Bay Aquarium (one of the main inspirations for Finding Dory’s Marine Life Institute), I had never seen manatees before and they are equally adorable and imposing due to their size and agility in the water. The large aquariums are full of several creatures and have TV screens that flash their names which makes this a great spot to cool off from the Florida heat by playing a game of I Spy with the kiddos. The sea turtles are usually pretty hard to spot because they like to hide! Each smaller aquarium also has short and sweet descriptions about the unique behaviors of the sea life within.
  3. Stave Church Replica and Museum in  Norway – Because the Norway pavilion has been overtaken by Frozen to a great extent, this museum is a nice way of tying together the movie and actual Norwegian culture. You can learn about all the inspiration for the film from the Norwegian landscape and traditional outfits, to how the instruments and vehicles are typically made and used.
  4. Oh Canada! – Even though I have been to Vancouver once before, this film taught me so much about Canada and made me want to visit again as soon as possible. The range of lifestyles represented – from small fishing villages to bustling, artistic city centers – and the sheer wonder of the various natural landscapes were absolutely fascinating, especially when presented in 360 degrees accompanied by Martin Short’s humor.
  5. Venetian Mask Shop – Besides showcasing the beauty and craftsmanship of what must be hundreds of masks, this little shop attached to the perfumery could have entertained me for hours due to what can be learned about Italian folklore. Ask the shopkeeper questions about your favorite masks and about the variety of designs; each one has its own meaning and story about the process of creating it. I may be biased because I read as many fictional books set in Venice as I could when I was in middle school but this really is a gem worth perusing when you’re still full on pizza and wine from Via Napoli.

Honorable Mention

Exhibits in Mexico

When I was last in Epcot in September, they were preparing for the promotional but potentially educational exhibit on Coco and Día de Muertos. I will have to check out the newly decorated area on my next trip to see if it is faithful to the culture, whether it teaches me anything different from my Spanish classes in school, and how it integrates aspects of the film. If it is anything close to the museum in Norway, it could be promising but perhaps difficult for kids who can’t read yet to be thoroughly entertained.

SpectacuLAB!

To replace Innoventions, the Imagineers decided an interactive science show would do the trick while also probably being less expensive to maintain and easier to potentially overhaul for the 50th anniversary of Walt Disney World. One of my top priorities for my next trip is checking out how engaging (and hopefully not cringe-worthy) this show is; maybe what some people see as cringe-worth is really just a good use of Jungle Cruise style humor to demonstrate cool science phenomena. I’m hopeful that this will be a memorable experience because it is co-sponsored by Science from Scientists which is a non-profit organization working to improve STEM literacy in schools.

What is your favorite educational experience at Epcot?

Science of Disney · Uncategorized

Science of Disney: Collecting

Disney fans might be some of the biggest collectors out there – whether its autographs, mugs, pins (my personal obsession and even the subject of this paper) or memorabilia of all sorts (looking at you, John Stamos). Disney has definitely capitalized on human tendency to want to collect things. But why do we collect?

Let’s Ask Neuroscience

Fundamentally, the reason that we do anything is because we receive a reward – typically a release of the neurotransmitter (which is just another name for a chemical in the brain) called dopamine – for doing something that satisfies a need. For example, when we eat Dole Whip, in addition to our digestive system breaking down the fats and sugars of the vegan soft-serve treat, our brain releases several molecules of dopamine that make us feel happy. The same kind of reward likely (I haven’t’ found any research studies looking at brains of collectors) occurs when a collector acquires a new item for his or her collection, which reinforces collecting as a desirable behavior.

First Time Having Dole Whip

Dopamine is also released during the process of expecting a reward. Based on studies with rats learning to obtain food, scientists at the University of Michigan found increased levels of dopamine in the mesolimbic area of rats’ brains in the steps leading up to receiving a pellet of sugar, including during the time in which the rat was literally taking steps towards the other side of the cage where the sugar was located. So dopamine in this area increases once I begin on writing a paper because the goal state of the paper being finished is that much closer. Is it possible that the same kind of process is at work during the several steps of collecting?

Hoarding

Much of our understanding of collecting comes from what we know about when collecting goes a step too far (have I used enough step colloquialisms yet?) and turns into hoarding. Hoarding is defined as collecting that interferes with an ability to use a room for its intended purpose. A few theories have been put forth as to why people start, continue, and find it hard to stop hoarding and dopamine plays a role here too.

One of the theories that seems to explain the other theories attributes hoarding behavior to differences in brain activity that underlie deficits in decision-making. The areas of the brain that are responsible for decision-making are found in the front-most part, called the prefrontal cortex. The prefrontal cortex is connected with many other parts of the brain, including dopamine pathways. However, exactly how the prefrontal cortex differentially affects dopamine changes in the mesolimbic area for hoarders versus collectors is not yet well understood.

Collecting Stories

Even though we know what parts of the brain are involved in hoarding and a little bit about how dopamine works in rats trying to obtain rewards, this isn’t quite the whole story about why we collect. Before we had fancy brain scanning techniques to study dopamine changing second by second, researchers used interviews to figure out why people are motivated to collect. Some of the most common reasons for collecting were:

1. Arranging and re-arranging – I think this is one of the biggest reasons I collect pins. I love figuring out how I want to display them either on pin boards or lanyards to take into the parks whether the lanyard is meant for trading with others or to just engender conversations with other park-goers.

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2. Social interaction as a result of collecting – The joy I get from arranging my pins ties into the social motivation of collecting through the conversations and memories I’ve made in the parks as a result of collecting pins but there are also lots of online and in-person communities to join and interact with for each unique collection. With so many Disney fans, every collector is bound to find someone to show off to or discuss with.

3. Competition and status over others – But there is another side to the social interaction that motivates other collectors who enjoy when they sense that they have moved up in the ranks of best collection. Bragging about acquiring a rare find for a great deal can make for a good story but also has effects on the storyteller’s and the listener’s dopamine pathways.

4. Investing – There are several Disney collectors who purchase rare items so they can sell them for a profit later. Often this can coincide with being motivated by acquiring knowledge of a particular kind of collection – more expert collectors know when to buy and sell items in a collection to turn the most profit and receive the greatest monetary and neural reward.

4. Sentimental value – Like most good souvenirs, items in a collection may have been rewarding to the collector because of the emotions or memory connected with them, whether past or future – some collectors collect because they want to leave a legacy and know that their items will live on past them. My personal pin collection is not solely for this reason. I deliberately try not to buy things just for them to remind me of one trip in particular and I often trade for pins rather unceremoniously with strangers on the Internet, but the act of finding a trading partner, going to the post office to mail a pin, and checking the tracking status of my incoming pin are most definitely ensuring that I will do it again and again.

So why do we collect? It could be any or all of the reasons I’ve discussed today. Or maybe we’re just following in Walt’s footsteps – he was quite the collector after all. Maybe we should examine the dopamine pathways left in his brain after all of these years…

What do you collect and why do you enjoy collecting? Let me know in the comments below and thanks for reading!


Citations
Anderson, S. W., Damasio, H., & Damasio, A. R. (2004). A neural basis for collecting behaviour in humans. Brain128(1), 201-212.
Hamid, A. A., Pettibone, J. R., Mabrouk, O. S., Hetrick, V. L., Schmidt, R., Vander Weele, C. M., … & Berke, J. D. (2016). Mesolimbic dopamine signals the value of work. Nature neuroscience19(1), 117.
Lafferty, B. A., Matulich, E., & Liu, M. X. (2014). Exploring worldwide collecting consumption behaviors. Journal of International Business and Cultural Studies8, 1.
McIntosh, W. D., & Schmeichel, B. (2004). Collectors and collecting: A social psychological perspective. Leisure Sciences26(1), 85-97.
Tolin, D. F., Stevens, M. C., Villavicencio, A. L., Norberg, M. M., Calhoun, V. D., Frost, R. O., … & Pearlson, G. D. (2012). Neural mechanisms of decision making in hoarding disorder. Archives of general psychiatry69(8), 832-841.
If you need help with hoarding, please see the following site: https://hoarding.iocdf.org/