Question of the Week

Here are all the questions we've asked as Questions of the Week since 1992 with links to the program where they first appeared. Look through the categories below for Questions that might be on your mind.

Space

	If it’s true that the Earth’s mass is increasing all the time though the arrival of 40-thousand tons of cosmic dust a year, could it be that gravity was weaker during the time of the dinosaurs?
	How did we get here before the light and other radio waves from the Big Bang, which was 13 billion years ago?
	Why do storms on other planets, like Jupiter, last for hundreds of years while storms here on Earth only last weeks?
	How often do Neptune and Pluto intersect orbits? And when will they collide?
	Can sounds be heard in space?
	Given that the universe is expanding “outward” and away from the point at which the Big Bang took place, how is it that the collision of two galaxies can take place?
	I’m wondering why galaxies are usually disc-shaped, or flat.
	If the tail of a comet is the debris from the core, wouldn’t the comet eventually exhaust itself of material?
	Why is it that after all these millions of years, the centre of the Earth is still molten? Why isn’t the energy source exhausted?
	Why are the rings of Saturn all aligned in the same plane?
	If the universe is continually expanding and cooling, will it eventually reach a temperature where life can no longer exist?
	What is the temperature of outer Space?
	While on a flight from Calgary, I saw snow and ice crystals race by the airplane window. Would I see something similar if I passed through the icy rings of Saturn?
	Is the Earth’s moon unique in our solar system, in the fact that we only see one side of the moon?
	I've read that the sun rotates every 25 days at its equator, but slower at its poles. How can this be?
	How long would we live if the sun went out?
	What causes planets and stars to rotate?
	Would all life in a galaxy be destroyed if it collided with another galaxy?
	Do stars really twinkle?
	Why do some planets have more moons than others?
	If Jupiter is a gas giant planet, where is the surface?
	How much material from space has accumulated on Earth over time?
	If Jupiter is a gas giant planet, where is the surface?
	Why is it that after the winter solstice, we seem to gain more minutes in the evening than in the morning? Why aren't the sunsets and sunrises symmetrical?
	How do we know how old the universe is?
	Is the sun losing mass?
	Why does the night sky appear dark?
	Could a satellite attach itself to the gravitational pull of a comet and tag along for the ride?
	Do the constellations change shape if you look at them from the Moon or Mars?
	What would we see if we moved closer to the centre of the Milky Way Galaxy?
	If an asteroid hit the moon, what would happen on earth?
	If one were to travel vast interstellar distances at a rate faster than the speed of light, would one be able to see much on the way?
	Are there places in the universe with 'null gravity'?
	What is the speed of gravity?
	Why does Uranus have a crooked orbit compared to the other planets?
	Where did the big bang happen?
	How much junk is there in space?
	Where does the organic material in comets come from?
	Which way would a magnetic compass point in space?
	How does a solar sail work?
	Where are we in the galaxy?
	How do astronauts adapt to life without an up or a down?
	Why is the moon moving away from us?
	Why is the sun's corona hot, but its surface is only warm?
	Does a ball dropped on the moon bounce higher or lower than the same ball dropped from the same height on the earth?
	When will the last solar eclipse be?
	What explains the apparently similar sizes of the sun and the moon?
	What is escape velocity?
	What is the dark side of the moon?
	Is there really such a thing as a blue moon?
	What shape would a flame be in space?
	How old is the moon, and why can we see it in the daytime?
	Why is the sun yellow?
	Why do we always see the same face of the moon?

Humans

	If humans are born with baby teeth, which are later replaced with permanent teeth, is this the case with other mammals as well? And why do most human adults have to have their wisdom teeth removed?
	Why, when I’m running, do I sometimes get a stitch in my side? What exactly is it and what can I do to prevent it?
	Are humans the only species that undergo menstruation?
	If a person infected with an illness like Hepatitis or AIDS uses a needle and it is discarded, how long is the needle dangerous for? What about other germs, like the flu virus or the common cold virus, on such things as doorknobs?
	Why would humidity curl hair?
	Why does my nose run when I’m outside on a cold day? And why does it stop running when I go back inside?
	Where do all the bacteria in our bodies come from in the first place?
	What causes blushing? And why do some people blush more than others?
	When I look at a white ceiling beside a dark burgundy wall, why is the image reversed when I close my eyes?
	What causes the odour in asparagus pee?
	Do a child and mother always have the same blood type? If not, then how do they share blood in the womb, since one blood group is fatal to the other?
	I think about sailors from our past, men who were at sea for weeks or months, who struggled with scurvy because they had no fresh fruits or vegetables. Why did the Inuit not have the same problem?
	Why does a person having a seizure experience auras?
	I’ve noticed that when I start running, it’s really difficult for the first 10 minutes, then it suddenly gets a lot easier. Why is that?
	Do those without vision ever suffer from motion sickness?
	How do our eyes focus and when I stare at an object and then close my eyes, why do I see an outline of the object, which fades over time?
	When you look a long way down from a high place, why do you feel like falling over?
	I remember seeing the Beatles on the Ed Sullivan show many, many years ago. I could understand them when they sang, but they spoke with heavy accents. Why do accents seem to disappear when people sing?
	What causes a lisp?
	If you lift your right foot and draw clockwise circles with it, and at the same time, try to draw the number six with your right hand, you'll find that your foot will always change directions. Why is that?
	My daughter was vaccinated against chicken pox and then caught it twice. Why is it that some vaccines don't work?
	Why do we cry when we are happy and sad, and are there any other animals that cry as well?
	Do we only use ten per cent of our brain, and if so, how do we use the rest of it?
	I’ve read several times that women who live together will often synchronize their menstrual cycles. What purpose might this serve, now or in the evolutionary past?
	What is the cause of muscle cramps? And could I counter them by a change of diet?
	When my mom gets migraine headaches, loud noise really bothers her. Why?
	Why does the human body produce ear wax?
	Why is human sweat salty?
	Why is one gene dominant over another?
	Why do we get dark circles under our eyes?
	I've been told that the eggs of mammals vary in size according to species. Do sperm also vary in size?
	Under extreme sleep deprivation, would a person eventually fall asleep anyway -- regardless of discomfort, bright lights, or screaming infants? And, can a person actually die from sleep deprivation?
	Why can some people float better than others?
	Does a menopausal woman experiencing a hot flash register an increased body core temperature, or is it just her perception of temperature that increases? And if it is an actual increase, would that be enough to set off a heat scanner at an airport?
	Why is it that when you tickle yourself, it is not ticklish, but when someone else tickles you, it tickles, even though you know they are about to tickle you?
	After a day of swinging on a swing, or swimming in the waves, why does my body continue to feel the motion when it is no longer moving?
	Where are our tears stored?
	Why are poly-unsaturated, mono-unsaturated, non-hydrogenated oils better for you than saturated oils, when it comes to cholesterol?
	Once upon a time, I thought I heard that the human egg can actually develop into a baby without the benefit of sperm; the resultant child would be a girl, of course. Is this true?
	Why does hair turn grey?
	Why don't we ever hear about cancer of the heart? Does it occur? And if so, why does it occur less frequently than other cancers?
	Why does a computer screen flicker when you take a bite of a carrot?
	if we presented paleontologists with the skeletons of contemporary humans. How many different human species would we would get?
	Why does a hard blow to the head produce unconsciousness?
	Is it true that a low pressure front can cause headaches? If yes, how?"
	Do we really need 8 to 10 glasses of water a day?
	How to antibodies in breast milk get into the baby's bloodstream without being digested?
	When I was young, my eyes were brown. I am now sixty and my eyes have become hazel. What's going on?
	Why do you see red after you stare at a green card for a long time? And ditto for yellow after staring at a blue card?
	Why do males have nipples?
	Why does looking into the sun make me want to sneeze?
	If the sun emits all different types of electromagnetic radiation, why have our eyes evolved to see only visible light?
	Do people's faces look the same now as they did 200, 300 or 1000 years ago?
	If you received a blood transfusion and then had a blood sample taken for a DNA test, whose DNA would show up?
	How do smells produce a gag reflex?
	Why do men develop deep voices at puberty?
	Why does our skin get wrinkled in water?
	Why did our brains develop a left and right side?
	Can you drink salt water? And how much could you add to fresh water to stretch your supplies when lost at sea?
	If one hotel guest uses a piece of soap, is it safe to leave it for the next guest?
	Do ovaries take turns?
	Who gets more exhausted: an athlete running all day, or a physicist thinking all day?
	Do we tear muscle in order to build muscle?
	What's the evolutionary role of ABO blood groups? Why do they exist?
	How does the immune system warm the body in fever, and how do common fever remedies control it?
	Why does long-term alcohol consumption cause distinctive changes to the nose and cheeks?
	Why do parts of our bodies feel the cold more after they've been frostbiten, rather than being less sensitive?
	If identical twin boys married identical twin girls from another family, would the offspring of one family be genetically siblings to the children of the other family?
	Why do our eyes get bloodshot when we cry?
	Do humans have circadian rhythms?
	Why do Parkinsons tremors stop when a person sleeps?
	How do sperm know which way to go?
	What makes a person left-handed or right-handed?
	Why do we yawn and are yawns contagious?
	How do the G.I. tract infections (stomach bugs) survive the acidity of their environment?
	Why don't tattoos come off when we shed skin cells?
	Why are humans still hairy after all these years?
	Why do our voices change as we age? (adulthood to old age)
	Why do our bodies produce so much mucus when we get a cold or the flu?
	What happens to the first cell created in the human body? Is it still ticking in an adult?
	Why do some people say 'um' when they're talking?
	Which has more calories, hot or cold milk?
	How are fingerprints formed?
	Why do some people feel the change in the weather in their joints?
	Why did the baker on the Titanic survive?
	Do snorers turn off their hearing?
	Why does aluminum foil make fillings hurt?
	What would we look like if we kept evolving?
	How does a cell know what to be (why doesn't a toe grow where an ear should)?
	Why do I get hiccups when I eat spicy foods (and where do they come from)?
	How can the brain hurt if it has no nerve endings?
	Why does coffee make your heart race?
	What happens to humans in a vacuum?
	Where do people come from in dreams?
	What's the evolutionary advantage of itching?
	Is it possible to use DNA to provide a 'snapshot' of a criminal?
	Why don't we fall out of bed when we sleep?
	Why do we feel sleepy in the afternoons?
	Why do nightmares and dreams wake us up?
	What's the biochemistry of being tired?
	Can you have more than one cold at a time?
	Why do people twitch and jerk as they are falling asleep?
	Why does body hair stop growing at a certain length?
	What is vibrato?
	Why do kids invert letters when they write?
	What am I seeing when I'm seeing stars?
	Why do mints make my mouth feel cold?
	Why do sleepwalkers walk?
	Why does a snorer never hear him or herself?
	Why do we swing our arms when we walk?
	Does hanging a chain from a car prevent carsickness?
	What causes an ice cream headache?
	Why do people get shorter as they get older?
	What is that feeling of being watched?
	How do you sweat while you're swimming?
	What is cat scratch fever?
	Why does human hair differ on different parts of the body?
	How do you tell if a baby was stillborn or died after delivery?
	Does taking vitamin B make a human body repellant to mosquitoes?

Plants

	I have always wondered if trees turn the same colour every fall. I realize that different species turn different colours, but does a sugar maple turn the same shade of red every year, or does the shade depend on the weather?
	When I take a cutting from a plant to make a new plant, I place it in water. I can often leave the newly rooted plant in the water and it survives. But when I over-water potted plants, they die. Why can a plant survive in pure water but be killed by over-watering when potted?
	Greenhouses often raise the CO2 levels in there to increase plant growth. So if the outdoor CO2 levels are increasing, due to climate change, shouldn’t outdoor plants be able to absorb the excess?
	I am wondering how fruit can be grown without seeds – such as seedless watermelon.
	How does a sunflower change position to face the sun, and does a Venus Flytrap do something similar to snap shut and catch flies?
	Is cancer strictly a disease of the animal kingdom, or can plants get cancer as well?
	What is the sticky stuff that falls out of maple trees and covers my car?
	What happens when the leaves fall off and there is no oxygen production?
	Why do some deciduous trees keep their leaves in winter?
	How do flower bulbs know which way is up?
	How do trees drink?
	Why does driftwood never seem to rot?
	Do plants filter toxins out of soil and air?
	Why do poinsettia leaves turn red?
	How does a Venus Flytrap close its leaves?
	How do giant pumpkins get so big?
	How do stinging nettles sting?
	How do seeds know which way is up?
	Do tropical trees have growth rings?
	How can some plants freeze during winter, while others can't?

Animals

	If birds have hollow bones, where do they produce marrow?
	Do most mammals have similar body temperatures?
	Do other animals have different blood types within their species, as humans do?
	If humans are born with baby teeth, which are later replaced with permanent teeth, is this the case with other mammals as well?
	Are humans the only species that undergo menstruation?
	Do fish get itchy?
	Why do Harbour seals consistently leave the land and dive back into the water when they see a killer whale, while sea lions go further inland?
	Is it true that at least 99 per cent of all species that have ever existed on this planet are now extinct?
	Do animals have the visual defects of myopia – nearsightedness, or hyperopia – farsightedness - like human beings?
	How do jackrabbits know when to change colour, and do some change faster than others?
	With so many birds in the world, why don't we see more dead birds on the ground?
	If whales and dolphins are mammals, but live in the sea, do they need to drink water as other mammals do, and if so, what do they drink?
	We place a lot of emphasis on washing our hands after using the bathroom and before handling food, so we don’t pass on germs. But my dog and cats have never washed their paws or faces with soap and water -- yet they stick their mouths and tongues in all sorts of things and places I don’t want to mention and they don’t keel over. Why not?
	If whales and dolphins are mammals, but live in the sea, do they need to drink water as other mammals do, and if so, what do they drink?
	What is the "species barrier", and how does it prevent viruses that infect animals from infecting humans?
	My partner and I acquired a one-year-old female cat at Christmas who, within a week, became the dominant cat in the household. Our four-year-old neutered male doesn't seem to know what hit him. Is this typical of cats in general or did this just happen with these two individuals?
	How do fish get into a lake in the first place?
	I have a six-week-old pup who has been separated from its mother. My other two female dogs have started to produce milk and one has taken over nursing the pup and all the motherly duties. Why did this happen, and does it happen in other species?
	If a poisonous snake bit itself, would it die from the bite? And, if a poisonous snake bit a snake of the same species, would it kill the other snake?
	Some animals can re-grow body parts or limbs. What enables them to do that?
	I’ve been noticing my cat eating our house plants and often wonder why this is?
	What protects vultures from the bacteria living on the carrion they eat?
	Dogs come in all sorts of shapes and sizes, as do birds. Why can dogs crossbreed while birds can't?
	Do whales have sweat glands?
	How fast can a flock of geese move?
	What's the largest species that outnumbers humans?
	Do cats develop cancer, or increase their chances of doing so, when they lie in the sun?
	How do spawning salmon find their way back to their home stream?
	When swallows fly at great speed into a small hole in a nesting box, how do they manage to stop within the next five inches, without slamming into the back wall of the box?
	If someone is bitten by a poisonous snake, should their rescuer suck the bite and spit out the venom?
	Does a skunk still have ammunition in reserve after it sprays, or does it have to wait for the supply to be replenished?
	When salmon migration is in full swing, testosterone embellishes the males in full red regalia, and they fight over females. Do the latter have any say? Do they, like females in other species, have a choice?
	Why do scientists believe that dinosaurs did not have external ears? Is it because the bone structure of the head is similar to the alligator/crocodile?
	Why is it that humans and most other animals need protein in their diets, whereas animals like cows and sheep can live and thrive on a diet of just hay and grass?
	I know that cats and dogs don't see color, but humans do. What other mammals see color?
	When our immune system is fighting an infection, we often get a fever. What kind of defense system do cold blooded animals have against sickness?
	When we humans pant excessively, we hyper-ventilate and get dizzy. How can dogs pant endlessly without losing consciousness?
	Spring has sprung here in Pictou county. The porcupines have helped themselves to several of the pine trees. Not that I'm going to approach these critters, but I've heard that porcupines will not release their quills while eating. Is this true?
	Why do some dogs go around in circles when they get excited? And why do some go anti-clockwise, but others go clockwise?
	Why don't the fish that swim under the polar ice freeze? Are their responses slower because of the cold?
	Why do our dogs' eyes look light blue in photographs when human eyes appear red?
	Why do birds such as pigeons bob their heads back and forth when they walk?
	Do animals who stay still for long periods of time lose muscle tone?
	How do chameleons change their colour? And why?
	Do all animals have finger prints? If so, why?
	Could our health be affected if the mite population in our skin is too low? And are the mites affected by shaving or applying make-up?
	What do hummingbirds feed their babies?
	Why do most mammals require their testicles to be air-cooled if they are to function normally?
	Why do cats appear to stare at nothing?
	How do giraffes deal with their height?
	Do birds collide with one another while flying?
	Why don't woodpeckers get concussions?
	Do orca whales have a sense of smell?
	How do squirrels' nests stay perched in the high branches of trees?
	Do hummingbirds really hitch rides with Canada geese?
	Can animals have allergies?
	How did my male cockatiel lay an egg?
	Why are there no green mammals?
	Is there such a thing as an iceworm?
	Do polar bears really eat people?
	Why do dogs wag their tails?
	How much can birds of prey carry in their talons?
	How do cats purr?
	How do birds keep their feet from freezing?
	Do animals have belly buttons?
	How can semen survive freezing?
	Why are robins sticking around this winter?
	Can a bird be left clawed?
	How can skunks stand their own smell?
	If cuckoos grow up in the nests of other birds, how do they know they're cuckoos?
	How can a female goat that isn't pregnant start producing milk?
	Do other animals have appendixes?
	How can a shark smell blood?
	Do animals lose muscle in hibernation?
	Why don't cats seem disoriented when they're woken up?
	How do birds all change direction or land simultaneously?
	Why don't birds on power lines get electrocuted?
	How do migrating birds know when to return?
	Are dolphins smarter than humans?
	Why haven't apes evolved into men?
	How can cats stay healthy without eating vegetables?
	Does double yolks lead to twin chicks?

Insects

	Do Insects have a sense of hearing?
	Most spiders are only the size of pinheads when they hatch. What do they eat when they're that small?
	I’ve noticed multitudinous black flies which seem to like hanging out in fairly cohesive globular clusters, maybe half a meter to a meter across and about a meter or two off the ground. What’s going on?
	Where do grasshoppers go in the winter?
	I was wondering why bugs are attracted to lights at night?
	Why do fireflies light up, and if other insects possess similar capabilities?
	Why is it that AIDS is apparently not spread by mosquitoes, as some other viruses are?
	What do the bumblebees on Baffin Island eat? And more importantly, how do they survive eight to 10 months of -30 to -50 degrees C. weather?
	Do mosquitoes prefer to bite some people over others?
	How do insect eyes accomodate different light levels?
	Why do insects gather on a person before a storm?
	How does a queen bee mate once, and then save the sperm to use in the future?
	Do insects sleep?
	Why don't flies fall off the ceiling?
	Why would ants attack a wasp's nest?
	How do maggots appear so quickly?
	Why doesn't a spider stick to its own web?
	Why does science say bees can't fly?
	What do spiders do with their thread when they climb up it?
	Where do fruit flies come from?
	What are snow fleas?
	Why do mosquitoes appear in winter?

Geography, Geology and Other Old Things

	Does the fossil record contain any information about the impact on flora and fauna from a reversal of the earth's magnetic field, and what would be its impact on climate?
	What is the source of the heat in the earth's core? And is there heat in the core of the moon?
	How deep in the earth's crust can you find living organisms?
	Modern society is generating much more heat today compared to before the Industrial Revolution … machinery, air conditioning, furnaces, cars, all pumping out heat … So my question is, has anyone tried to quantify the amount of additional heat introduced into the environment by today’s society – and does it contribute to global warming?
	I heard that we could fix global warming if everyone on the world jumped at the same time, pushing the earth into a farther orbit. Could this actually work?
	There was talk after the tsunami in Southeast Asia about a large earthquake changing the actual size of the earth, and thus its rotation time. Is that possible, and if so, did it happen? And is it also true that the earthquake caused the Earth to wobble?
	Are there known events on the Great Lakes that resemble a tsunami, producing a wall of water?
	How high could a mountain get before it sinks into the ground?
	What influences sound as it travels across a lake?
	When oil is tapped from the ground, it comes out under tremendous pressure. So when the "pool of oil" is depleted, and the oil is no longer exerting pressure, what "holds the earth up"? Does the crust subside?
	What would the world be like now if the asteroid that wiped out the dinosaurs had missed the Earth?
	Is it true that the St.Elias Mountains are rising at a rate of 4 cm/year? If so, how do scientists measure the growth of mountains?
	While travelling along the shores of Lake Superior when it is quite windy, we have noticed that there seems to be a pattern in the size of the waves. I have heard that waves build in size on a cycle of seven, while my boyfriend has heard four. Is this true, and if so, who's right?
	Each motor vehicle driving down the highway gulps down thousands of cubic meters of oxygen every minute. Literally every industrial process uses huge amounts of oxygen. Where is it all coming from and could we run out?
	Why is there a height difference between the Atlantic and Pacific Oceans, even though they are connected by the Panama Canal?
	How long does it take a drop of water to travel from Lake Superior to the Atlantic Ocean?
	Is there a section of the Atlantic Ocean where an underwater shift could occur, resulting in a tsunami that could affect the Atlantic Coast? Has this research been done, and if so, what are the possible implications?
	Since the earth began as a molten mass and now the earth is 70% water - where did all the water come from?
	Is there a reason South America, Africa and India all point south?
	Why do earthquakes originate from a single point, rather a continuous line along the fault?
	What is the record for Earth movement in one seismic event?
	What time is it at the North Pole?
	Why is glacier water green, when water from creeks is clear or brown?
	Are the recent low water levels in the Great Lakes the cause of recent earthquakes?
	What was the earth to water ratio when the continents were one big landmass years ago?
	How do rock paintings, or pictographs, keep their colour over time?
	How is sea level measured, is it a constant?
	What will the world look like in millions of years?
	Why can people smell salt in the air near the ocean?
	What would happen if the earth's magnetic field was reversed?
	What did dinosaur taste like?
	How long does it take to capture an insect and form amber?
	What's an undertow?
	What causes the evenly spaced ripples on a beach?
	Why were dinosaur predators all bipeds, while mammal predators are all quadrapeds?
	Could you clone a wooly mammoth from its frozen body?
	Why is the ocean salty?
	Why do so many animals have giant ancestors?
	How far south does permafrost extend?
	Why are there no fossils of transitional forms?
	How did dinosaurs get enough food through their tiny heads?

Weather & Climate

	Does the fossil record contain any information about the impact on flora and fauna from a reversal of the earth's magnetic field, and what would be its impact on climate?
	Is the current level of oxygen in the atmosphere dropping, due to fossil fuels and greenhouse gases? And how much CO2 does there need to be in the air before we have trouble breathing?
	Why, when it’s really cold, does snow squeak when you walk on it, but when it is warmer, it doesn’t squeak?
	How many mature trees does the average Canadian adult need, to offset that person’s greenhouse gas production?
	It seems to me that thunderstorms happen more often in the afternoon and evening than in the morning. Is that true, and if so, why?
	We live on Baffin Island, and the weather here is very dry, even though the island is surrounded by water. But when we go to Cape Breton Island, we notice that the weather there is very wet. Since they're both islands, why is there such a difference in humidity?
	I see in the papers that fossils of a carnivorous dinosaur have been found in the Arctic. Clearly the climate there was warmer during the time of the dinosaurs. But how much of the increased temperature was due to the earth being warmer, and how much to the Arctic landmass being closer to the equator at that time?
	We know the jet stream is related to changes in our weather. And as we see on the Weather Channel, there are significant changes every day in the jet stream. I’d like to know what causes these changes?
	Why are the colours reversed on a double rainbow?
	What influences sound as it travels across a lake?
	Why is it that when we have violent snow storms in the winter, we never get thunder and lightning?
	Why is snow white?
	I have read in several sources that during the period when the Norsemen colonized Greenland and visited Newfoundland at around 900-1100 AD, the weather was unusually warm and calm. Do we know the causes behind this period of warming, and is it possible that the current 'global warming' is simply the next repetition of a cycle?
	I know that there is a wind chill factor that makes us colder in the winter. But are there circumstances that could produce a wind hot factor?
	Why does the weather sneak up from the west?
	At what point does moving air (or moving through air) change from cool to hot?
	What causes the turbulence we feel when we're in an airplane?
	How much do clouds weigh?
	Would there be any difference in climate if Earth didn't have the moon?
	Why does the pitch of the howling wind change when the wind blows harder?
	What is that smell you smell when it starts to rain?
	Would a polar melt cause a European ice age?
	What gases were in the atmosphere in ancient times and how did their composition come to change?
	How can ice form at the bottom of a river first?
	How dry is dry cold?
	What exactly is windchill?
	Why do modern windmills only have two or three blades?
	Why do hurricanes move in the opposite direction to other storms?
	What is ball lightning?
	How much rain is there in a rain cloud?
	Why does rain fall in droplets?
	How does a triple rainbow form?
	How do we get hail on a hot summer day?
	Why doesn't rain fall in lumps?
	Does the atmosphere have tides, and does that affect our weather?
	How fast do raindrops fall?
	Can the ozone hole be fixed?
	Does the calm before the storm exist?

Material Science

	If dimples on golf balls allow them to go faster and farther, why not put dimples in ships’ hulls, and the outer surface of aircraft?
	As I shave using a gel for shaving cream, I keep wondering how the gel turns into a foam when I apply it.
	What is it in pemmican that keeps it preserved?
	When coffee goes stale, it seems to change colour, so that when milk is added to the old coffee, it is a completely different colour. It's appears gray instead of brown. What’s going on?
	Why does some metal jewelry stain the skin?
	Why is glass clear even though the sand that it is made out of isn't?
	What happens to all the rubber that wears off the millions of tires that are on the vehicles on our roads?
	How does sunscreen work, and if I apply SPF 15 to my body twice, is it the same as using SPF 30?
	Are there more grains of sand on a beach, such as Long Beach on Vancouver Island, or more atoms in a single grain of sand?
	How can paraffin wax be dangerous?
	Why does pita bread have a pocket in the middle?
	If beer is amber and air is clear, why is beer foam white?
	What is quicksand?
	Why do eggs explode in the microwave?
	What happens to mercury in a thermometer at really low temperatures?
	Is water the only know substance that gets bigger when it changes from a liquid to a solid?
	Why are sand grains on a beach all the same size?
	Why do tennis balls come in vacuum packed tubes?
	Why do icicles form on ice-cube trays?
	Why do little balls of yarn appear on sweaters?
	Why do supermarket bags stick closed unless you wet your fingers?
	Why does wool feel warmer than metal?

Physics

	Why are electrical plugs now polarized, so that one prong is bigger, and the plug can only go into the socket one way?
	Why do light bulbs burn out?
	Why can you sometimes see lights or objects that are over the horizon, and invisible most of the time?
	This New Year it was announced that one second was being added to the year to compensate for the decrease in the rotation of the Earth. Is that the rotation of the Earth on its axis or the revolution of the Earth around the sun?
	Why does a kettle get louder until it boils, and then suddenly gets quiet again?
	Why can’t you put metal in the microwave?
	If we could travel to distant nebulae, is there a distance where, to the naked eye, the nebulae would look like the colourful pictures taken from the Hubble Telescope?
	I often see beautiful pictures of gas clouds in star-forming regions. I'd like to know the average gas density of these clouds, compared to our atmosphere.
	How close can our planet get to the Sun before it is too hot for us to survive?
	Why is it easy to balance my bicycle when it is moving and almost impossible to balance when it is sitting still?
	Were the oceans always salty, and if so, has the salinity changed since the oceans were first formed?
	Would you be able to fire a gun in space, and if so, would you be able to hear it?
	What happens when we whistle while exhaling, and while inhaling?
	Will a cannonball fired straight up from the equator fall straight back down into the barrel of the cannon? And would it be any different at the North Pole?
	How deep would you have to dig on Mars to reach one atmosphere of pressure?
	Why are planets spherical?
	When you watch someone on a swing, you usually see them lean back and stretch their legs out forward on the pump stroke. Would it be more efficient to swing with the legs draped downward rather than outstretched, and how does pumping make you go higher anyway?
	What happens when airplanes are struck by lightning? Is there some form of protection in place?
	Could the force of the Halifax explosion have pushed all the water out of the harbour?
	Is there a way airflow from a speeding car could be harnessed to help provide power to the vehicle?
	Can a skydiver really feel the rain as he falls through it? Wouldn't the rain fall faster?
	Why do we have no sensation of movement here on earth, despite the fact the earth is rotating, orbiting and gravity is pulling on us?
	If you were in a spinning habitation cylinder in space, like the one in the movie 2001, what would happen if you jumped off the floor? ---- Some people disagreed with our answer ---
	What happens if you have a rope running over a frictionless pulley, with a monkey on one end and an equivalent weight on the other end, and the monkey starts to climb up the rope?
	How Tall Can a Structure Be?
	What would happen if birds started flying around in the cargo hold of a plane - would the plane get lighter?
	What makes the earth complete a full rotation every twenty-four hours?
	How does light behave inside a mirrored ball?
	What would happen if the earth stopped spinning?
	When I stand near my radio or put my hand on my TV antenna, I influence the reception. Why?
	Does centrifugal force really exist?
	What happens when lightning hits a lake?
	Why does my hair stand on end in the damp rain at the beach?
	Why does hitting nails together make them into weak magnets?
	Why don't round shoelaces stay tied as long as flat ones?
	If a spring is compressed and tied in position with a cord, and then dissolved in a beaker of acid, where did its potential energy go?
	Is there an absolute hot?
	If you could drill a hole straight through the earth, and if you could slide down the hole you drilled, would you float weightless at the centre of the earth?
	Why does my cup of hot chocolate change tone when I stir and tap it?
	Why is a perpetual motion machine impossible?
	How high would I need to turn up my stereo to hear it in a vacuum?
	Can I save myself jumping in a falling elevator?
	Why doesn't honey splash when dropped in a cup of tea?
	How does light change speed in glass?
	Are X-rays reflected in a mirror?
	What's the pressure in my upturned glass?
	Why is it harder to paddle a canoe is shallow water?
	What is a neutrino?
	How does an airplane fly upside down?
	Does ice contract when the temperature drops?
	What is friction?
	Why does a piece of a broken Christmas bulb reflect larger or upside down images?
	Why can a sharp sound break glass?
	How do bicycles stay up?
	Why do objects appear smaller to us the further away they are?

Chemistry

	Why does whole wheat bread seem to rise more slowly, even though more yeast is used than in white bread?
	Can your breath actually turn into a solid and fall to the ground in extreme cold?
	Why can’t they make a dryer that grounds the machine, to let off all the static electricity that is created inside?
	Could the Athabaska tar sands catch fire? What would happen if someone generated a spark on a very hot summer day, with volatile fumes rising from the tar sands?
	Why are things sticky?
	I made ice cubes the other day and one of them had an icy "antenna" sticking out of it. What's going on?
	What creates the sparks when two rocks are banged together?
	How does a camera flash cause damage to a work of art, such as a painting?
	It is suggested that hanging a silver spoon – and only silver – inside the neck of an open champagne bottle can prevent the champagne from going flat. Is this the case, and if so, why?
	Why does a mere drop of water cause chocolate to clump? Is there anything I can do to make the chocolate free flowing again?
	How does road salt melt snow and ice on the road?
	How does seawater freeze and manage to leave the salt out of the ice?
	How does fabric softener stop the generation of static electric charge?
	How are the calories in food measured?
	Why does oil change colour when frying?
	Why do newspapers go from white to yellow and white again in sunlight?
	Why doesn't air separate into layers?
	Why does newspaper ink come off on my hands when I read the paper, yet stay put on the paper when I clean my windows with a sheet of it?
	Why does microwaved coffee fizz?
	How do antiperspirants work?
	Why does diet cola foam more than regular cola when it's poured over ice?
	How does soap work?
	What is the smell of fresh air?
	How do hot water, soda and aluminum foil remove tarnish?

Other oddities

	Why does whole wheat bread seem to rise more slowly, even though more yeast is used than in white bread?
	Why does powdered curry become less intense as it ages, while sitting on your shelf; but become more intense when it has been in a sauce, overnight in the fridge?
	Why is it that you can put pop or beer in the freezer and when you take it out, it’s still liquid, but as soon as you open it, it begins to freeze?
	Why is it that a glass of cold water feels so much colder when you drink it after eating a peppermint candy cane, brushing your teeth with mint toothpaste, or chewing mint gum?
	It's a well known fact that urine is drinkable and some even claim it is good for you. But can you repeatedly recycle the same liquid?
	Why does temperature affect the flavour of food? A food that is delicious when hot, like mashed potatoes, can be disgusting when cold.
	Why do fried and salty foods taste so good?
	Why does seafood go smelly so quickly, and what causes the smell?
	If there were no obstacles on a clear day, how far could someone who is six-feet-tall see, and is there a difference if you are five-and-a-half-feet versus six-feet-tall?
	Is it better to idle or turn off your engine when stopped at a red light? Which causes more pollution?
	Why does hot water coming out of a tap make a different sound from cold water?
	Why does the noise in a kettle increase in volume until just before the boiling point and then go silent for a brief time?
	How do search engines work?
	Will we eventually run out of note combinations to create new music?
	Why do orchestras tune to A440?
	Where do bullets go when they're shot straight into the air?
	How do you set an atomic clock?
	Why do wheels roll in front of a vehicle when they fall off?
	Why do wheels look like they're going backwards on T.V.?
	When does the millennium begin?
	Why do we see tiny white lines at the tips of a fighter plane's wings when it turns?
	Where do the units of time we use come from?
	How is music recorded on a CD?
	A question about strange number sequences.
	How thick a coin has a 50-50 chance of landing on its side?
	How do 3D dot pictures work?
	Does a brick in the toilet tank save water?
	Are railroad companies always aware of where the box cars are?