What is lighter: warm air or cold air?
The molecules in cold air are packed closer together making it more dense and heavier than warm air. Air expands when heated. The more water vapor is in the air, the less dense it becomes.
A baseball will travel further on a warm humid day. The air is less dense and the ball travels with less friction.
What is the process that circulates air around the globe?
Air tries to equalize things and wind acts to keep things in balance. Warm air, being lighter, rises and cool air falls.
Convection makes the Earth livable by removing excess heat from the surface and transporting it high into the atmosphere.
Weather at the equator is generally stable and predictably fair. Warm moist air rises until it hits the tropopause (the invisible barrier between the troposphere and the stratosphere) where it spreads out. It then travels away from the equator and moves toward the poles. As it moves, it cools and then sinks.
If warm air did not rise into the atmosphere, what would be the average temperature on the surface of the earth?
The Earth absorbs heat from the sun. Convection helps to make our planet livable by moving excess heat from the surface and transporting it into the atmosphere. As warm air rises, cold air rushes in to replace it.
The average temperature of the surface of the Earth is 59°F. Without convection, researchers have estimated that the surface air temperature would rise to ~125°F.
At times, air temperature feels colder than the thermometer reads. Why?
The human body works to maintain a consistent temperature. It will lose heat through convection. Our bodies transfer heat from our skin to the atmosphere surrounding it.
When wind blows across your skin, you lose heat which makes you feel colder. As the wind blows faster, heat is carried away at an accelerated rate. Two effects operate. One is that wind causes skin to equilibrate with the air temperature faster. The other is that it speeds the evaporation of skin moisture which is a cooling effect.
Wind chill is the perceived decrease in air temperature due to the combination of wind and temperature. Meteorologists use the wind chill index, a system that takes into account the cooling effect of the wind speed in addition to the thermometer reading.
Wind chill temperatures are always lower than the air temperature. If it feels warmer, one refers to the heat index.
True or False: Wind chill can make an inanimate object feel colder than the surrounding air.
Living beings may feel colder than the temperature around them but wind chill does not affect inanimate objects the same way.
Wind helps warmer objects reach the air temperature more quickly than without it, just like skin, but the object will not be colder than the surrounding air temperature no matter how fast the wind blows, unless you first wet it and get the cooling effect of evaporation.
What is the result when excess water vapor condenses and rises?
All clouds are made of the same thing: condensed water or ice.
Clouds form when warm rising air cools to the point where some water vapor molecules “clump together” faster than they are torn apart by thermal energy.
What is the name of the low-pressure area where trade winds meet at the equator?
You may be familiar with the phrase “in the doldrums”, meaning a period of stagnation or slump, but it is an actual place on Earth.
Trade winds are the prevailing pattern of easterly surface winds found near the equator. Doldrums are found between the belts of the northern and southern trade winds where the winds are neutralized. The Doldrums are known for their calm atmosphere. The lack of wind can trap sailing ships for days and even weeks.
It is believed that the word doldrum, meaning a fit of sloth or dullness, was already in use in the early 19th century. The region now known as The Doldrums was not named until later that century when ships unable to progress were described as being “in the doldrums”.
What is larger: a virus or a bacterial cell?
Bacteria are unicellular microorganisms, typically a few micrometers long, and varying in shape.
Bacteria are prokaryote cells with no true nucleus. They consist of a semi-fluid substance bound by a plasma membrane. They contain enough DNA to program metabolism and just enough enzymes and cellular equipment to sustain themselves and reproduce.
Bacteria are structurally simple and very small, typically 1 -10 µm in diameter. A virus is even smaller, typically 20 – 450 nm in size
What happened that finally allowed scientists to see viruses in the 1930s?
The invention of the electron microscope in 1931
Viruses had been identified by the late 1800s, but they were too small to be seen with the optical equipment at the time. In 1931, the electron microscope was invented by two German researchers. Electron microscopes can see objects as small as the diameter of an atom. Researchers began to get a look at these simple, tiny, biologically active particles.
Viruses are not cells. They have no nuclei or organelles. They cannot carry out metabolic activity. They are made up of RNA or DNA, a protein covering, and an enzyme or two. In their infectious state, viruses attach to a cell and hijack its replication process. They use the cell’s equipment make copies of themselves, take over the cell, and proliferate wildly.
Viruses cause smallpox, polio, German measles, chicken pox, mumps, and influenza.
Noble laureate Peter Medawar described viruses as “a piece of bad news wrapped in a protein.”
What cellular structure is the primary site for protein synthesis?
Ribosomes, particles made from ribosomal RNA and protein, are the organelles that carry out protein synthesis.
Ribosomes are found suspended in the cytosol of the cell, or attached to the outside of the nuclear envelope or endoplasmic reticulum.
Ribosomes consist of two major subunits. The small subunit reads the base sequences of messenger RNA and the large subunit joins the amino acids to form a polypeptide chain. The two subunits come together to translate the RNA. Once finished, they split apart.
In eukaryote cells, what cellular structure is the primary site for converting DNA to RNA?
DNA is organized into chromosomes and stored in the nucleus of a eukaryotic cell. DNA is transcribed into RNA within the nucleus. That RNA strand then travels outside the nucleus to the ribosome where it is translated into protein.
Bacteria lack nuclei. Their DNA is not segregated from ribosome. Bacteria can begin to build proteins while the DNA is still being translated.
What is our body’s first line of defense against invading foreign substances?
Our immune system
The immune system is a combination of biological structures and processes within an organism that protects the organism from disease.
We are born with an innate immune system that recognizes a broad range of microbes. It detects the difference between own healthy cells and the invading agents and then activates an immune response to destroy the unwanted cells.
We can also acquire immunity. If we have been exposed to microbes, abnormal body cells, toxins, or other unwanted foreign substances, our bodies react and learn how to fight off these types of infections.
Our immune system helps our bodies to adapt to changing external circumstances.
What major medical tool helps to prevent viral infections?
Vaccines are harmless variants or derivatives of pathogenic microbes that stimulate the immune system to mount defenses against the actual pathogen.
Once our bodies have encountered a specific pathogen, it retains an immunological memory that remembers how to fight off subsequent infections.
Vaccines have controlled many infectious diseases throughout the world including polio, measles, diphtheria, pertussis, rubella, mump, tenatus, and eradicated smallpox.
What major medical tool helps to prevent viral infections?
Our bodies are composed of eukaryotic cells. Bacteria form their own kingdom distinct from eukaryotes or prokaryotes. Bacteria’s machinery for DNA replication, transcription, translation, and basic metabolism is different than ours.
Antibiotics are drugs that have been developed to specifically inhibit processes in bacteria without disrupting them in the host.
Not all bacteria in our bodies are bad or even unwelcome. Some types of bacteria help us maintain our normal healthy processes.
Do we have more human cells or microbial cells in our body?
Microbial cells. More. Much more.
The human body is a nutrient-rich, warm, and moist environment. Many microorganisms have evolved the ability to survive and reproduce there. Microorganisms like bacteria reside on all surfaces exposed to the environment like the skin, nose, eyes, and mouth. They are also found inside the body with the vast majority in the large intestine.
Bacteria produce chemicals to help us break down and harness energy from our food. Researchers believe that bacteria also help boost immunity by protecting us from disease-causing bacteria that might come from food and water.
Our bacteria help us keep a healthy physiology unless their number grows beyond their typical range due to a compromised immune system, or microbes populate atypical areas of the body due to poor hygiene or injury.
Bacterial cells are much smaller than human cells. There are at least ten times as many bacterial cells as human cells in the body (approximately 1014 versus 1013 ).
You could say a human organism is only about 10% animal cells.
The mass of microorganisms found over and in our bodies is studied as one unit. What is it called?
Each one of us is an organism and a densely populated ecosystem.
The collection of microbes inhabiting our bodies is called our microbiome. Some researchers consider it a “newly discovered organ” since its existence was not generally recognized until the late 1990s.
The interaction between our bodies and our microbiome is complex and dynamic.
The microorganisms that inhabit our bodies help us to digest food and absorb nutrients. They manufacture vital vitamins and anti-inflammatory proteins. They train our immune system to combat infectious intruders.
When was the first antibiotic discovered?
Alexander Fleming discovered the first antibiotic, penicillin. Since its first use in the 1940s, medical care was transformed. Antibiotics have dramatically reduced illness and death from infectious diseases.
Fleming’s discovery helped conquer some of our most ancient scourges including syphilis, gangrene, and tuberculosis.
Because bacteria are living organisms, they can evolve to reduce or eliminate the effectiveness of drugs. Fleming very early discovered that using too little penicillin or using it for too short of a time could cause the bacteria to become resistant to antibiotics.
He cautioned antibiotics should be used only when there was a properly diagnosed reason for it, and that if it were to be used, never to use it too little or too short a time.
What do we call microorganisms that are beneficial to health?
Probiotics are also referred to a “good bacteria” or “helpful bacteria”. Most of the bacteria found in our bodies are in the stomach and intestines. A decrease in good bacteria can cause digestive problems.
Probiotics have been around for a long time. They can be found in fermented foods and cultured milk products. Probiotics are also available as dietary supplements but the FDA has not approved any health claims for these products.
When antibiotics are used to kill infectious bacteria, they kill the good bacteria along with it
A recent study* in the Journal of the American Medical Association supported taking probiotics when taking antibiotics. The research suggested that the probiotics reduced the side effects of the drug, helped the “good bacteria” to recover quickly, and restored balance to the body.
*Hempel, Newberry, Maher, Wang, Miles, Shanman, Johnsen, Shekelle (2012) Probiotics for the prevention and treatment of antibiotic-associated diarrhea. JAMA 307(18):1959-1969.
New research suggests we should “feed” our good bacteria with complex carbohydrates. What is this “food” called?
Prebiotics are special forms of ingredients found in food that nourish the good bacteria (or probiotics) already in the digestive system. The body does not digest this type of dietary fiber made from plants.
Prebiotics are allowed to pass to the large bowel and colon where they can act as a kind-of fertilizer to promote the growth of good bacteria. Prebiotics can be found in chicory root, artichokes, garlic, leeks, onions, and bananas.
Why does popcorn pop?
Because of water inside the kernel
Each popcorn kernel contains a small amount of water stored in a circle of soft starch inside a hard outer casing.
When heated to ~450°F, the moisture turns to steam creating pressure within the kernel. As pressure builds the casing gives way, allowing the water to escape as steam and turns the kernel inside out.
Can any type of corn pop?
Popcorn is a type of maize (or corn), a member of the grass family, scientifically known as Zea mays everta. Of the six types of corn – pod, sweet, dent, flour, flint, and popcorn – only popcorn pops.
Popcorn differs from the other types of corn in that it has a thicker hull and a dense starchy center. The hull allows the natural water within the kernel to build up pressure as it is being heated. When the kernel finally explodes, the starch spills out giving popcorn its familiar shape.
Popping corn is the number one use for microwave ovens.
Georges de Mestral, a Swiss engineer, went for a walk in the woods in 1941. After examining the burrs that clung to his trousers – and his dog – he wondered if this concept could be turned into something useful. What did Georges de Mestral invent?
After walking in the woods in 1941, French engineer George de Mestral loosened a burr stuck to his dog’s fur and examined it under a microscope. A cocklebur is a maze of thin strands with burrs, or hooks, that grab onto fabric or fur.
After nearly eight years of research, de Mestral successfully reproduced the natural burr-like attachment with two strips of fabric. One side had thousands of tiny hooks and the other had tiny loops. When pressed together the two sides form a strong bond. He named the invention “velcro” – a combination of “velvet” and “crochet”.
Velcro is considered to be a “zipperless zipper”. It is strong, easily separated, durable, washable, and won’t jam like a zipper.
What is the new type of science that looks to Nature for models of problem-solving methodology?
Biomimicry (from bios meaning “life”, and mimesis meaning “to imitate”) is the study of organisms and ecosystems intended to guide the search for sustainable solutions to living on Earth.
Animals, plants, and microbes are the consummate engineers. They have found what works, what is appropriate, and most importantly, what lasts here on Earth.
The idea is that Nature has already solved many of the problems that we are grappling with: energy, food production, climate control, transportation, packaging, and more. By examining Nature, we can extract solutions that work in the most effective and efficient manner. We can learn from the natural world to solve our human problems.
After 3.8 billion years of evolution, Nature is a model of what works and what lasts.
The Eastgate Centre in Zimbabwe based its ventilation system on the air circulation systems found in the mounds of what type of insect?
Termites in Zimbabwe build gigantic mounds where they farm a fungus that is their primary food source. The fungus must be kept at exactly 87° F while the temperatures outside range between 35°F at night and 104°F during the day.
The termites open and close a series of vents throughout the mound over the course of a day. The air is sucked in the lower parts of the mound and pushed up through channels throughout the structure.
The termites constantly dig new vents and plug up old ones to keep the temperature steady.
The ventilation system at the Eastgate Centre, modeled after termite mounds, was made without conventional air conditioning and heating. Like a termite mound, air is drawn in through the first floor and is pushed up through vertical supply ducts. Fresh air replaces stale air and exits through exhaust ports on the ceilings of each floor.
The Eastgate Centre, built using biomimicry principles, allows the building to maintain a constant comfortable temperature with dramatically less energy consumption – it cost less than 10% to run this building compared to conventional buildings of similar size.
Swimsuit manufacturers based the design of competitive swimwear on the skin of what sea-based animal?
Competitive swimmers would like to replicate the high-speed efficiency and buoyancy that sharks have developed over their 400 million year evolutionary odyssey. Although sharks seem to glide effortlessly through water, their skin is anything but smooth.
The skin of a shark is made up of very small individual scales called dermal denticles or “little skin teeth”. Each scale is ribbed with longitudinal grooves that help move water over the shark more efficiently than a smooth surface. The scales channel the flow of water and speed up the slower water at the skin surface.
Speedo designed swimsuits for competitive racing based on the patterns and movement of sharks’ skin. These sharkskin-inspired suits received a lot of attention when Michael Phelps wore them in the 2008 Olympics in Beijing.
In fact, twenty-three of the twenty-five records broken in the 2008 Olympics were made by swimmers wearing LZR racer swimsuits. Some people believe these suits are so technologically advanced that wearing one is essentially “technology doping”.
After the Olympics, the world governing body for swimming placed stricter restrictions on wearing these types of sharkskin suits in competition.
Why do paint companies study the wings of butterflies? (Hint: it has nothing to do with color)
Butterfly wings are self-cleaning.
Like the swimsuit manufactures, paint companies learned from nature.
Many large winged insects (butterflies, moths, dragonflies) have wings that remain dirt free without expending any energy due to the topography of their wings and the physical properties of water.
Their wings have raised areas that are superhydrophobic (extremely non-wettable). As water molecules collect on their wings, they are prompted to stick together into droplets and roll off these areas. Dirt attaches to the water and when the wing is angled, gravity pulls the water and dirt off together, cleaning the wing.
The self-cleaning Lotusan exterior house paint uses the same microstructure principle found on the wings of insects (and lotus leaves). The highly water-repellent coating resists dirt and will be automatically cleaned during a rainstorm.
Butterfly wings have superhydrophobic areas that repel water. What do we call areas that attract water?
In a 2001 article in the journal Nature*, Oxford scientists describe a dime-size Stenocara beetle living in the Namib Desert in Africa.
Unlike the bumps on butterfly wings, this beetle has superhydrophilic (really loves water) bumps on its back that gather moisture out of the morning fog. Water molecules collect on the tip of the bump and cluster together. When they are big enough, they slide down into hydrophobic channels and roll in the beetle’s mouth.
Scientists have created synthetic surfaces that mimic this type of water collection, which may be able to bring clean freshwater supplies to arid areas of the world without the need for pumping.
*Parker and Lawrence (2001) Water capture by desert beetle. Nature 414:33-34.
When Japanese engineers designed high speed bullet trains, they looked to what type of animal for examples of quiet motion?
When they first came into being, ultra-fast bullet trains would emit loud booms when exiting tunnels. The original rounded shape of the front of the train caused a cushion of air to build up in front of the train and explode as it left the tunnel.
A Japanese engineer watched a kingfisher bird dive through the air into water without making much of a splash. Its bill made it ideal for transitioning from air into water.
The engineer redesigned the front of the bullet train to mimic the elongated cone shape of the kingfisher’s bill. The newly remodeled trains reduced the air friction caused by moving in and out of tunnels and eliminated the sonic booms.
Engineers also examined the way air flows across the wings of owls and incorporated into their designs.
Design elements found in birds helped technology become more aerodynamic, efficient, and quiet.
Researchers created a new kind of glue based on what kind of organism known for its adhesive ability?
Mussels and other marine organisms secrete a remarkable protein-based fluid that undergoes in situ crosslinking or a hardening reaction leading to the formation of a solid, flexible adhesive plaque.
These adhesives retain their powerful bonding properties in water and are comparable in strength to human-made glues but without carcinogens such as formaldehyde.
By mimicking mussels’ ability to cling to rocks in churning waters, researchers have developed synthetic polymers that can stay in place in wet environments.
A researcher in British Columbia (Christian Kastrup) has invented a blood vessel glue based on the structure of the gel secreted by mussels.
The new substance stays in place in a very dynamic environment with high flow velocities.
What is the shape of this rotor based on?
Jayden Harmon, an inventor, studied flow efficiencies found in natural systems such as air and ocean currents. He observed that nature never moves in straight lines but tends to flow in spiral paths.
He isolated the archetypal spiral geometry found in lilies (and nautilus shells and whirlpools) and invented the Lily Impeller.
The design of this rotor takes advantage of nature’s flow pattern, known to be the most effective and least resistant way of mixing liquids. It uses less energy in the mixing process and significantly reduces the noise normally associated with other mixers.
The Lily Impeller is used in municipal reservoir tanks to keep drinking water from becoming stagnant and reduces the need for disinfectant additives.
The Lily Impeller is known for the beauty of its efficiency but is also recognized for the beauty of its design. The prototype is owned and has been exhibited by the Museum of Modern Art.
What type of companies look to swarms of insects to help develop new and innovative products?
Flocks of birds, schools of fish, and swarms of bees have “swarm intelligence”. These animals and insects travel in tight packs without colliding. Individuals move together as a group.
In addition to making cars lighter and more fuel efficient, research and development groups are working on reaction mechanisms found in nature that could be built into their structure. For example, locusts fly in swarms of millions without hitting each other. Their neural circuitry sends visual input directly to their wings for instantaneous flight adjustment. Volvo is developing an on board “sensory input routing methodology” to help eliminate collisions.
Nissan is working on autonomous vehicles that mimic the schooling behavior of fish. Fish swim together at the same speed. They avoid collision based on their position. Nissan has designed robot cars that travel side-by-side, matching distance to speed, that are programmed to avoid accidents.
Crowded highways may become faster AND safer if we learn from examples in nature.
Biomimicry is the idea of studying and adapting nature to solve human problems. Evolution has been testing and retesting designs, patterns, and organizations for nearly 4 billion years. If it doesn’t work, it doesn’t last.
The examples shown in the past few weeks have only skimmed the surface.
More information can be found here asknature.org.
What do we call animals that are active during daylight?
Our biological "clocks" are set to the 24-hour rotation of the earth. The daily light/dark cycle governs rhythmic changes in behavior and physiology of most species. Many animals develop distinctive behavioral patterns depending on their environment, and light is a powerful biological force.
Nocturnal animals are active at night when light is minimal. They have highly developed senses of hearing and smell, and specially adapted eyesight.
Animals active during the day when light is plentiful are described as diurnal. Humans are diurnal creatures with eyes adapted to living in the sun's light.
Plants can also be diurnal or nocturnal. They adapt to the time of day when their most effective pollinators visit the plant.
What do we call those animals that are active primarily during twilight?
Twilight occurs at both dusk and dawn. Visibility is more challenging at these times of day. Some living creatures find it easier to avoid both diurnal and nocturnal predators by foraging as the sun is setting or rising.
Animals such as cats and rabbits as well as insects such as moths, beetles, and flies are crepuscular.
When was the first electric streetlight invented?
The earliest street lamps were used by the Greek and Roman civilizations. Throughout the years the lamps burned oil, kerosene, candle wax, and gas.
The first electrical lamps were invented in the early 1800s. Two carbon rods, in a gas plasma, were spaced head-to-head a small distance apart. When electricity flowed through the rods, the space between them created an arc of light when the current vaporized the gas.
Sir Humphry Davy, an English engineer, invented the arc lamp using two charcoal sticks and a 2000 cell battery. Davy’s lamp created a blindingly bright light that was impractical and too expensive for homes or most businesses.
In 1876, a Russian engineer, Pavel Yablochkov developed an “electric candle”. Yablochkov turned the rods so they were parallel to each other and separated by a layer of Plaster of Paris.
This new design allowed the light to burn longer and more efficiently, and was perfect for illuminating public spaces.
What city first used this electric arc lighting?
Pavel Yablochkov continued to improve his electric candle. He developed an alternating current generator, an AC transformer, and a system that would allow multiple candles to be lit at once.
The first major installation of the Yablochkov Candle was at the Grand Magasins de Louvre, a department store in Paris. When French businessmen saw its potential, they established a company to manufacture and market it.
In 1878, during the Paris Exhibition, sixty-four arc lamps were installed on the Avenue de l’Opera. The huge success of the candles brought electric lighting into the public eye. These arc lamps quickly spread throughout Europe and to the United States.
One American engineer was following Yablochkov’s inventions from his lab in New Jersey. Who was it?
Thomas Edison was already well known in 1878 having invented the phonograph and the stock market ticker. He had earned the nickname “The Wizard of Menlo Park”. Around this time, Edison turned his attention to the advances made in using electricity to generate light and hoped to make an electrical lamp for indoor use.
Scientists knew that if you passed electricity through certain materials they would heat up and glow. The main obstacles in creating light with electricity were the materials. If they got hot enough, they would either burst into flame or melt into a puddle.
The first thing scientists did was to encase the materials in glass “bulb”.
Why would a sealed glass container prevent the materials from bursting into flame?
Glass bulbs with the air pumped out were created to encase the components. If oxygen could not reach the materials, they could not ignite.
The second major problem was the materials themselves. Electricity needed to pass through a filament inside the bulb. A variety of filaments were tried but most burned too quickly to be practical.
Edison experimented with different substances eventually settling on carbonized bamboo filaments. His new light bulbs used very little electricity and could burn for 600 hours. It was the first long-lasting practical incandescent light bulb that could be mass marketed.
When Edison exhibited his light bulbs to the public in 1882, he was quoted as saying “We will make electricity so cheap, only the rich will buy candles.”
It was not long until Edison’s nearly perfect incandescent light bulbs totally replaced arc lamps.
When did the electric streetlighting come to the United States?
An engineer from Ohio, Charles F. Brush, perfected Humphry Davy’s arc lighting and made an electric lamp that was practical to manufacture.
Brush demonstrated his carbon arc lamp on April 29, 1879 and lit a public square in downtown Cleveland. This newfangled lamp was used to illuminated streets, buildings and public places.
What environmental consequence occurs as a direct result of outdoor electric lighting?
Darkness and night are no longer synonymous.
When outdoor lighting becomes inefficient, annoying, and unnecessary, it is light pollution. Most of the planet’s light pollution comes from streetlights. Streetlights shine down where it is needed but also up into the atmosphere where is not. Light overpowers the darkness. Glare scatters in the atmosphere creating a glow around cities.
The lighting of urban areas began as a security measure. It has progressed to the point where now most of humanity lives under intersecting domes of reflected light from overlit cities and suburbs, light-flooded highways, and illuminated buildings.
Light pollution prevents us from seeing what lies beyond us in the universe. Stars are virtually unseen.
It is considered one of the fastest growing and pervasive forms of environmental pollution.
When a massive power outage hit southern California in the 1994, Los Angeles residents reportedly called 911 to report a “giant silvery cloud” in the sky. What were they actually seeing?
The Milky Way
Because of light pollution, it is estimated that two-thirds of the U.S. population have lost the ability to see the Milky Way.*
During an earthquake in 1994, power left many southern California residents in the dark. Unaccustomed to seeing the night sky as it truly is, they believed the strange clouds might be some sort of ominous presence and called the authorities to report it.
In an attempt to curb light pollution and preserve Arizona’s night skies, Tuscon has adopted a strict policy to control excessive and careless outdoor lighting. Tuscon is also home to the International Dark-Sky Association (IDA), which works to preserve the night. It aims to protect wildlife, cut energy waste, and stop light pollution.
The Milky Way can be seen by the naked eye from the heart of downtown Tuscon, Arizona.
*Chepesiuk, R (2009) Missing the dark: health effects of light pollution. Environ Health Perspect 117(1):A20–A27.
Excessive light can disrupt our 24-hour day/night schedule. What is this cycle better known as?
Light is a strong biological force.
Before electricity, we got 12 hours of darkness whether we were asleep or not. With the day artificially extended, our circadian rhythms are disrupted. Disturbing our circadian clock is linked to several medical disorders in humans including depression, insomnia, cardiovascular disease, and cancer.
Artificial light alters animal and plant behavior. Breeding cycles are disturbed and foraging is disrupted when animals are exposed to excessive light. Trees and plants have trouble adjusting to seasonal variations. Birds alter their migration patterns.
Light pollution affects every living thing on earth.
Besides light pollution, what natural entity also prevents us from getting a good look at the stars?
A full moon is 100,000 times brighter than the brightest of nighttime stars. The brightness of the full moon reduces the number of stars visible to the unaided eye from thousands to hundreds.
The physics of reflection angles endows the full moon ten times the brightness of the half moon. The moonglow reduces the number of meteors visible during a meteor shower. Astronomers are identifying the depths of darkness as a means to measure what we are losing.
The National Park Service has a “Night Sky Team” that considers darkness a natural resource like clean air and water. Its aim is to preserve darkness and to leave it unimpaired for future generations.
"When you look at the night sky, you realize how small we are within the cosmos. It's a kind of resetting of your ego.
To deny yourself that state of mind, either willingly or unwittingly, is to not live to the full extent of what it is to be human."
- Neil de Grasse Tyson
Director of the Hayden Planetarium at the American Museum of Natural History in New York
Water draining from Lake Erie into Lake Ontario must pass through what international landmark?
Niagara Falls is a collection of three falls: the Horseshoe Falls, the American Falls, and the Bridal Veil Falls. They straddle the international border between the United States and Canada.
One fifth of all the fresh water in the world lies in the four upper Great Lakes: Michigan, Huron, Superior, and Erie. The outflow of these lakes empties into the Niagara River and eventually cascades over the falls.
3,160 tons of water flows over Niagara Falls every second. It falls 32 feet per second hitting the base of the falls with 280 tons of force at the American and Bridal Veil Falls, and 2,509 tons of force at the Horseshoe Falls.*
In the late 19th century, businessmen and engineers hoped to capture this energy and convert it to electricity.
Next week's question:
Who constructed the first major world’s first major hydro-electric power plant at the Niagara Falls?