Veritasium
What Is The Coastline Paradox?
- Title
- What Is The Coastline Paradox?
- Runtime
- 2:16
- Date posted
- 15 years ago
- Description
- How long is the coastline of Australia? One estimate is that it's about 12,500 km long. However the CIA world factbook puts the figure at more than double this, at over 25,700 km. How can there exist such different estimates for the same length of coastline? Well this is called the coastline paradox. Your estimate of how long the coastline is depends on the length of your measuring stick - the shorter the measuring stick the more detail you can capture and therefore the longer the coastline will be.
- Title
- Candle Trick
- Runtime
- 1:35
- Date posted
- 15 years ago
- Description
- How to light a candle without touching a flame to the wick. A common misconception is that a candle burns by burning the wick. What is actually burning is wax vapour which is drawn up through the wick. When you blow a candle out, wax vapour continues to rise off the candle so you can light this vapour which burns back down to the wick, relighting the candle.
- Title
- How To Make Graphene
- Runtime
- 3:41
- Date posted
- 15 years ago
- Description
- My entry to the techNyou Science Ambassadors competition, visit www.facebook.com/talkingtechnology and www.youtube.com/technyouvids to find out more about these guys.
- Title
- What Causes The Phases Of The Moon?
- Runtime
- 4:33
- Date posted
- 15 years ago
- Description
- What causes the phases of the moon? The common incorrect answer is the shadow of the Earth. The phases of the moon are actually just a result of our perception of the moon's half-illuminated surface. When the moon does pass through Earth's shadow the result is a lunar eclipse. This can be spectacular as the moon turns a deep shade of red.
Images courtesy of NASAimages.org and Geoff Wyatt, Senior Astronomy Educator Powerhouse Museum
- Title
- A Human Being Is A Part Of The Whole
- Runtime
- 1:57
- Date posted
- 15 years ago
- Description
- A quote by Einstein: A human being is a part of the whole, called by us "Universe", a part limited in time and space. He experiences himself, his thoughts and feelings as something separated from the rest — a kind of optical delusion of his consciousness. This delusion is a kind of prison for us, restricting us to our personal desires and to affection for a few persons nearest to us. Our task must be to free ourselves from this prison by widening our circle of compassion to embrace all living creatures and the whole of nature in its beauty. Nobody is able to achieve this completely, but the striving for such achievement is in itself a part of the liberation and a foundation for inner security.
- Title
- What Is The Magnus Force?
- Runtime
- 3:47
- Date posted
- 15 years ago
- Description
- Whenever an object spins through the air it experiences a 'Magnus Force' due to friction between the air and the object's surface. This force was originally identified while studying the trajectories of cannon balls (though earlier observations of this effect exist). The Magnus force is essential in most ball sports including golf, cricket, tennis, and baseball.
At the end the ball demonstrations were conducted with a 100 mm diam polystyrene ball and the launcher was made by bending a long, thin, aluminum rod and bolting the ends to a block of wood as a handle.
Music was provided by Kevin McLeod (incompetech.com) Scissors and a stock clip from FCP.
- Title
- Atomic Rant
- Runtime
- 2:58
- Date posted
- 15 years ago
- Description
- How should we depict an atom? Like a solar system with electrons orbiting the nucleus on hula hoop orbits? That idea is so last century! Bosi takes us into the quantum world, where an electron's position and velocity aren't well defined - all we can calculate are the probabilities e.g. of finding an electron at different points in space. When we do that, we find electrons do not neccessarily occupy circles or spheres in space. Rather their probability densities make all sorts of interesting shapes from the dumbell to the peanut with the donut around it.
- Title
- Can You Go the Speed of Light?
- Runtime
- 4:13
- Date posted
- 15 years ago
- Description
- Einstein's classic thought experiment involves sitting on a train travelling at the speed of light. If you hold a mirror in front of your face, will you see your reflection in a mirror? How could light from your face reach the mirror if the mirror is travelling away from you? But it would be a pretty spooky train if you couldn't see your reflection so Einstein felt this solution wasn't realistic. On the other hand if you could see your reflection, it would mean light was travelling at the speed of light inside the train. But that meant the same light observed from outside the train would be going twice the speed of light. This again seems inconsistent. So Einstein resolved that you must see your reflection but that light must travel at the same speed inside and outside the train. The only way this is possible is if space and time are perceived differently by observers inside and outside the train.
- Title
- Physics Nobel Prize 2011 - Brian Schmidt
- Runtime
- 7:13
- Date posted
- 15 years ago
- Description
- The Nobel Prize for physics in 2011 was awarded to Brian Schmidt, Adam Riess, and Saul Perlmutter for discovering that the universe is expanding at an accelerating rate. This finding was completely unexpected because it was thought that gravity should slow the expansion of the cosmos. The best current explanation of why the universe is accelerating is that there is some energy tied to empty space which pushes matter apart. This 'Dark Energy' makes up 73% of the universe but is very difficult to detect. Images courtesy of NASA/NASAimages.org and Maritza A. Lara-Lopez
- Title
- Nobel Prize Winner Brian Schmidt - Physics 2011
- Runtime
- 2:40
- Date posted
- 15 years ago
- Description
- The Nobel Prize for physics in 2011 was awarded to Brian Schmidt, Adam Riess, and Saul Perlmutter for discovering that the universe is expanding at an accelerating rate. This finding was completely unexpected because it was thought that gravity should slow the expansion of the cosmos. The best current explanation of why the universe is accelerating is that there is some energy tied to empty space which pushes matter apart. This 'Dark Energy' makes up 73% of the universe but is very difficult to detect. Hopefully a better understanding of it will lead to a unification of our theories of gravitation and quantum mechanics.
Images courtesy of NASA - NASAimages.org
- Title
- Supersized Slow-Mo Slinky Drop
- Runtime
- 3:03
- Date posted
- 15 years ago
- Description
- What happens when a super long slinky is dropped?
- Title
- Make Plasma With Grapes In The Microwave!
- Runtime
- 5:31
- Date posted
- 15 years ago
- Description
- When a grape is cut nearly in half and placed in a microwave, plasma is produced. Please use caution if attempting this experiment: don't leave the microwave on for too long, make sure the area is well ventilated, and stand back. Remember the contents will be very hot afterwards.
- Title
- Slinky Drop
- Runtime
- 0:57
- Date posted
- 15 years ago
- Description
- What happens when a slinky that has been extended under its own weight is released? How does it fall to the ground? Answer link: http://www.youtube.com/watch?v=eCMmmEEyOO0
- Title
- Slinky Drop Answer
- Runtime
- 3:31
- Date posted
- 15 years ago
- Description
- Want more awesome HD slow-mo? http://www.youtube.com/watch?v=uiyMuHuCFo4
Slinky not long enough? Click here: http://www.youtube.com/watch?v=JsytnJ_pSf8
How does a slinky fall when extended by its own weight and then released? We discover the surprising answer using a slow motion camera that records 300 frames per second. Answer link: http://www.youtube.com/watch?v=oKb2tCtpvNU
For a great explanation, check out Rhett Allain's analysis here: http://www.wired.com/wiredscience/2011/09/modeling-a-falling-slinky/
- Title
- Slinky Drop Extended
- Runtime
- 1:58
- Date posted
- 15 years ago
- Description
- The answer to the question - what happens to a tennis ball tied to the bottom of a slinky after the top of the slinky is let go?
For a great explanation, check out Rhett Allain's analysis here: http://www.wired.com/wiredscience/2011/09/modeling-a-falling-slinky/
- Title
- States of Matter
- Runtime
- 4:53
- Date posted
- 15 years ago
- Description
- Everyone is familiar with liquid water, ice and water vapour, but what are the differences between these three states of matter? Solids, liquids and vapours of the same substance differ in the motion of the molecules and the distance between them.
Animations courtesy of VisChem (Trade Mark), Copyright 1995, Roy Tasker. Thanks for all your help!
- Title
- Imploding Drum
- Runtime
- 5:01
- Date posted
- 15 years ago
- Description
- The atmosphere applies a pressure of about 100 000 N to every square metre on Earth's surface. We take this pressure for granted because we have the same amount of pressure pushing out. But what happens when the pressure of the atmosphere is applied to an object with no outward pressure? It implodes. In spectacular fashion.
- Title
- What Colour Is Most Attractive?
- Runtime
- 2:40
- Date posted
- 15 years ago
- Description
- Scientific research has shown that heterosexual males and females find members of the opposite sex more attractive when they wear the colour red. This is a subconscious preference that seems to have some evolutionary basis. We attempted to replicate these findings in Sydney but our methods were much less controlled and the results achieved were not statistically significant.
- Title
- Chain Drop Answer 2
- Runtime
- 2:42
- Date posted
- 15 years ago
- Description
- Which weight hits the ground first - the free weight or the weight attached to the chain?
- Title
- Chain Drop Experiment
- Runtime
- 0:38
- Date posted
- 15 years ago
- Description
- On a mobile device? Click here: http://www.youtube.com/watch?v=X-QFAB0gEtE for the answer
Two 1.5kg masses are released simultaneously from the top of a 10m high wall. One is attached to a chain while the other is free. Which one will hit the ground first?
- Title
- Impress Her With Nanodiamonds
- Runtime
- 1:28
- Date posted
- 15 years ago
- Description
- Scientists have recently discovered nanodiamonds in the flames of ordinary candles. They are produced at a rate of about 1.5 million per second. Unfortunately they are also burned up at this rate and released into the atmosphere as carbon dioxide. Still this finding may prove useful in the ongoing search for economical ways to produce diamonds.
- Title
- What Is Water Made Of?
- Runtime
- 1:07
- Date posted
- 15 years ago
- Description
- It's the most abundant liquid on the planet and by weight we are about 60% water. But do we know what it is made of?
- Title
- What Is Chemistry?
- Runtime
- 1:32
- Date posted
- 15 years ago
- Description
- 2011 is the international year of Chemistry. But what do Australians know about it?
- Title
- Ice Cutting Experiment
- Runtime
- 1:18
- Date posted
- 15 years ago
- Description
- On mobile, click here for the answer: http://www.youtube.com/watch?v=qQCVnjGUv24
When ice is put under pressure, its melting point decreases. When that pressure is removed it goes back to being solid. This process is known as 'regelation'. In this experiment regelation of ice is attempted with copper wire and fishing line of the same diameter. Which will pass through the ice first?
- Title
- Ice Cutting Experiment
- Runtime
- 2:52
- Date posted
- 15 years ago
- Description
- What passes through a block of ice more quickly, copper wire or fishing line?
- Title
- Does Pressure Melt Ice?
- Runtime
- 1:38
- Date posted
- 15 years ago
- Description
- When pressure is applied to ice, its melting point is reduced so it turns to water. When the pressure is removed, however, it turns back into ice. This process is called 'regelation.' Big thanks to Art of Ice Sculptures www.icesculpture.com.au who donated the beautiful block of ice.
- Title
- Why Is Ice Slippery?
- Runtime
- 2:54
- Date posted
- 15 years ago
- Description
- In Sydney, ice melts because it is warm out in the middle of the day (even in winter). This creates a layer of water on top that certainly makes it slippery. But should it be slippery at night or in a cold northern climate where the air temperature is below zero? Yes, because the pressure your skates apply to the ice actually lowers its melting point allowing you to glide along a thin layer of water.
Animation in this video is courtesy of VisChem (TM), Copyright 1995, Roy Tasker
For a more complete picture of the mechanisms involved in making ice slippery, check out this great article: http://lptms.u-psud.fr/membres/trizac/Ens/L3FIP/Ice.pdf
- Title
- How Does The Earth Spin?
- Runtime
- 4:42
- Date posted
- 15 years ago
- Description
- One of the most common physics misconceptions is that an unbalanced force causes constant motion. In truth, an unbalanced force leads to changes in motion - accelerations.
- Title
- Why Does The Earth Spin?
- Runtime
- 2:52
- Date posted
- 15 years ago
- Description
- The Earth spins on its axis, completing a full revolution every day. By why does it do this? One of the most common misconceptions in physics is the belief that constant motion requires a constant force. So many people believe there must be some force in the Earth (e.g. gravity, centrifugal force) that keeps it spinning. In truth, no force is required because a fundamental property of mass is that it maintains its state of motion in the absence of external forces. This property is called inertia.
- Title
- Persistence Of Vision
- Runtime
- 2:49
- Date posted
- 15 years ago
- Description
- Everything is not as it first appears. This simple plastic ball looks purple until you swing it in a circle and reveal its true nature. Inside are three light emitting diodes (LEDs), which are red, green and blue. They turn on and off in sequence very quickly. When still, the ball appears purple because your eyes and brain don't 'refresh' quickly enough to perceive the changing colours. However, when swung in a circle, the ball changes colours at different locations so the colours don't merge with each other and the ball's true nature is revealed. Now let's not think too carefully about how this illusion is conveyed through video (because the camera doesn't refresh quickly enough to perceive the colours changing either - so you have no hope of seeing it on YouTube even frame by frame).
- Title
- Fire Syringe
- Runtime
- 3:19
- Date posted
- 15 years ago
- Description
- When air is compressed very quickly, it can reach high temperatures. In this demonstration we show how cotton wool can reach the point of auto-ignition by quick compression of air in the fire syringe.
- Title
- Misconceptions About Heat
- Runtime
- 5:11
- Date posted
- 15 years ago
- Description
- When we touch something that is hot or cold, what are we actually sensing? Is it the temperature of the object, or the rate at which heat flows between the object and our hand?
- Title
- Can You Solve This Shadow Illusion?
- Runtime
- 3:32
- Date posted
- 15 years ago
- Description
- When sunlight shines through a small hole, it casts a circular image on the wall regardless of the shape of the hole. The size of the hole also doesn't affect the size of the image.
This counterintuitive demonstration shows that the hole is acting like a pinhole camera, producing an image of the sun on the wall. Therefore the size and shape of the hole have no effect on the size and shape of the image.
- Title
- Can You Perceive Acceleration?
- Runtime
- 3:34
- Date posted
- 15 years ago
- Description
- How do our eyes scan across a landscape? Contrary to popular belief, they don't scan smoothly across a scene, they observe a series of images. The eye is capable of panning smoothly however. If something moves in your field of view, your eyes track it smoothly. This has an important effect on our perception of motion. It makes it more difficult to see when objects are accelerating since the eye tracks all motion quite smoothly.
- Title
- Option E - Acceleration of a Bungy Jump
- Runtime
- 0:35
- Date posted
- 15 years ago
- Description
- On the rebound, the acceleration varies. The jumper is accelerating up but as the bungy recoils, the jumper starts accelerating down again due to the pull of gravity. This does not mean that he's moving down, however, only that his velocity upwards is decreasing.
- Title
- Option D - Acceleration of a Bungy Jump
- Runtime
- 1:02
- Date posted
- 15 years ago
- Description
- Congratulations, the acceleration of the bungy jump is greatest at the jumper's lowest point. This is because the bungy is now stretched to its maximum, meaning if applies a force up on the jumper more than twice his weight. This means he accelerates up at a greater rate than the acceleration down when he left the platform.
- Title
- Option C - Acceleration of a Bungy Jump
- Runtime
- 0:45
- Date posted
- 15 years ago
- Description
- At the jumper's fastest point, the acceleration is by definition zero. That is because the jumper is going from speeding up to slowing down. At this instant then there is no change in the jumper's velocity. This is counter-intuitive for a lot of people because it's easy to confuse velocity with acceleration. Velocity is how fast something goes while acceleration is the rate at which velocity changes.
- Title
- Option B - Acceleration of a Bungy Jump
- Runtime
- 0:24
- Date posted
- 15 years ago
- Description
- When the rope becomes taut, the force on the jumper is mainly his weight downwards, plus a bit of air resistance up. Therefore his speed is increasing nearly as much as it did when he leapt off the platform. So this is not the greatest acceleration of the jump.
- Title
- Option A - Acceleration of a Bungy Jump
- Runtime
- 0:32
- Date posted
- 15 years ago
- Description
- Right after leaving the platform, the only significant force acting on the bungy jumper is his weight. This causes him to speed up from rest. His speed increases every second by nearly 10 m/s. This is not the maximum acceleration experienced by a bungy jumper, however.
- Title
- When Is A Bungee Jumper's Acceleration Max?
- Runtime
- 1:06
- Date posted
- 15 years ago
- Description
- When is the acceleration (rate of speeding up or slowing down) greatest during a bungy jump?
- Title
- Veritasium Bungee Jumps!
- Runtime
- 3:10
- Date posted
- 15 years ago
- Description
- In Queenstown, New Zealand, I jumped off the Kawarau Bridge - the site of the first bungy jump. It was a thrilling experience, preceded by a terrifying, gut-wrenching half hour wait. All in all an awesome adventure, even if the woman fitting my harness didn't know the first thing about the acceleration of free-falling bodies.
- Title
- Where Did The Earth Come From?
- Runtime
- 3:57
- Date posted
- 15 years ago
- Description
- Do we take the Earth for granted? It gives us life and sustains us in the manner we're accustomed to, but we don't know the first thing about it: like where did it come from? And how did it form? Most people recognize that the Earth has a big explosion in its history, which they refer to descriptively as the 'Big Bang.' But there are two very good reasons why the Big Bang is not directly responsible for forming the Earth: 1) It happened 13.7 billion years ago. That's more than 9 billion years before the Earth formed (what happened during that time?), and 2) After the Big Bang the universe consisted of only Hydrogen and Helium - not great raw material for building the Earth. The truth is the big bang formed stars, which exploded and then (perhaps) formed more stars, which exploded and then formed our solar system, including the Earth. The early stars performed the vital role of making the heavier elements of which Earth is composed and we are made.
- Title
- How Old Is The Earth?
- Runtime
- 2:47
- Date posted
- 15 years ago
- Description
- The Earth is clearly old, but exactly how old was difficult to work out. People long believed the Earth had only existed for several thousand years. Then, in the 1800's, a study of geological features (including fjords) led scientists to the conclusion that the planet must be much older - at least millions of years old. Later, the discovery of radioactivity provided a mechanism by which the Earth's core could be continually heated. This meant it was much older than previous estimates of 20-40 million years based on the cooling rate of the Earth. Today through many different methods we have established that the Earth is roughly 4.54 billion years old!
- Title
- What Is Electricity? (Are You Gonna Be My Girl?)
- Runtime
- 3:59
- Date posted
- 16 years ago
- Description
- 1, 2, 3 A song about 'lectricity
because it powers our lives
makes it possible for us to thrive
because it powers our lives
makes it possible for us to thrive
Oh, 4, 5, 6, volts of potential difference
makes electrons go round
if the circuit is complete and sound
Circuit's closed
Voltage There
Current Flows
Power Everywhere
We use AC,
in factories
and homes because we can transform it
High voltage
transmits with lower loss
but low voltage is best for safety
I said what is electricity?
Well, so 1,2,3 a song about 'lectricty
because it powers our lives
makes it possible for us to thrive
because it powers our lives
makes it possible for us to thrive
Oh, 4,5,6 volts of potential difference
makes electrons go round if the circuit is complete and sound
Heat makes steam
turns tu...
- Title
- Types of Radiation
- Runtime
- 2:55
- Date posted
- 16 years ago
- Description
- An introduction to alpha, beta, and gamma radiation
- Title
- Sound + Fire = Rubens' Tube
- Runtime
- 4:03
- Date posted
- 16 years ago
- Description
- Sound waves in a tube of gas create flames of different heights that dance to the music. A metal tube with holes in it is filled with gas. The gas is lit to create a row of tiny flames. A speaker at one end plays sound into the tube, which creates a standing wave of sound: areas where air molecules are vibrating rapidly separated by areas where the air is fairly still. This produces the different heights of flames and allows the wavelength of the sound wave to be estimated.
- Title
- Radiation vs Radioactive Atoms
- Runtime
- 3:01
- Date posted
- 16 years ago
- Description
- There seems to be confusion about what radiation is and where it comes from. Many people believe it is the radiation that comes directly from nuclear power plants that poses a threat to public safety. In fact it is the radioactive atoms, which can escape in the event of an explosion, that pose a safety risk. They can be scattered by the wind over hundreds of kilometres. Then they may be ingested or breathed in. If they release radiation at this point, it is damaging to the body's molecules and cells because the radiation is delivered directly to tissues.
- Title
- Galileo the Scientific Parrot
- Runtime
- 2:36
- Date posted
- 16 years ago
- Description
- On the surface of Earth all objects accelerate downwards at the same rate - at least, they're supposed to. But we all know dust, pieces of paper, and feathers fall slower. This is of course due to the influence of air resistance. In this experiment we use an evacuated cylinder to test whether a coin and feather really do accelerate at the same rate.
- Title
- What Powers Australia?
- Runtime
- 3:18
- Date posted
- 16 years ago
- Description
- Countries are powered by a diverse range of energy sources, but in Australia electricity generation mainly has one source: fossil fuels. Coal, natural gas, and oil account for over 90% of the country's electricity. Hydro provides 7% with only 0.3% provided by wind and solar. Should Australia consider nuclear power? It is a complicated issue leaving many uncertain about its place in Australia's energy future.
- Title
- How Damaging is Radiation?
- Runtime
- 3:59
- Date posted
- 16 years ago
- Description
- What is radiation? Are all types harmful? What are the most common sources of damaging radiation? Most people view radiation as harmful and negative without understanding what makes it potentially damaging and which forms should be avoided. For example, many felt radiation from mobile phones probably caused cancer but few focused on the carcinogenic effects of UV rays.

