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.
Many videos on YouTube show water freezing almost instantaneously. This video shows you how to replicate the experiment and it explains how the phenomenon works. Molecular illustrations are courtesy of:
PhET Interactive Simulations
University of Colorado http://phet.colorado.edu.
Most people recognize that atoms are the fundamental building blocks of all matter around us. An atom itself is composed of protons, neutrons and electrons. The simplest atom is the hydrogen atom because it consists of only one proton and one electron. If a neutron is added to the nucleus, the atom is still hydrogen, just a more massive version. Atoms of the same element (i.e. those with the same number of protons) but different numbers of neutrons are called isotopes.
A short a cappella tribute to experimentalists. It is sung while performing three simple experiments with household items: Mentos dropped in diet Coke, a tea bag emptied and burned, and a ping pong ball floating in the air stream of a hair dryer.
If you’ve seen footage from the International Space Station or any of the space shuttle missions, you know that astronauts float around as they orbit the Earth. Why is that? Is it because the gravitational force on them is zero in space? (Or nearly zero?) The truth is that the strength of the gravitational attraction is only slightly less than it is on Earth’s surface. So how are they able to float? Well, they aren’t floating – they’re falling, along with the space station. They don’t crash into the Earth because they have a huge orbital velocity. So as they accelerate towards the Earth, the Earth curves away beneath them and they never get any closer. Since the astronauts have the same acceleration as the space station, they feel weightless. It’s like being in a free-falling elevator (without the disastrous landing).
Director of Photography: Stefan Smith
Camera Assistant: Raa Perajeev
Boom Operator: Maha Sivalingam
Production Coordinator: Adrian Tan
Production Assistants: James Peniata, Pratheep Ramachandran
Force is a central concept in physics. By analysing the forces on an object, its resulting motion can be determined. But what exactly is a force? The word force is used in everyday language in a variety of contexts, only some of which reflect the scientific definition of force. In this video, people at Victoria Park in Sydney are interviewed on their ideas of force and the forces that act on them.
A song about Gravity set to the tune of John Mayer’s Gravity.
Gravity is working with me
And Gravity, keeps me on the ground
All mass attracts all other mass
a force proportional to mass one and two
and inversely to the distance between them squared
Oh, gravity is working with me
and gravity, makes apples fall to ground
Oh twice the mass has twice the pull
but the force on each is still equal
It keeps the moon and the satellites
going round
Oh twice the mass has twice the pull
but the force on each is still equal
It keeps the moon and the satellites
going round
Oh gravity, the force that makes weight on me
Woah, gravity, now general relativity (how can that be?)
The force between us all is
The force between us all is
The force between us all is
Gravity between us all is
Gravity between us all is
Gravity between gravity between us all is
Well an atom’s made of protons, neutrons, and electrons
the first two in the nucleus, the third around it
it’s mostly empty space, but it feels solid in any case
The elements are all the different types of atoms
they differ by the number of protons in the middle.
Hydrogen has only one, but Uranium has a ton
It’s just chemistry that you and me are made of these atoms
Well atoms bond together to form molecules
Most of what’s surrounding me and you
Water, sugar, things yet undreamed of of of of
Look around you, see the combinations in a eucalypt tree
Mendeleev’s periodicity
gives us sand and water and the air above ove ove ove ove
It’s just chemistry that you and me are made of these atoms:
Hydrogen, Oxygen, Carbon, Nitrogen, make up the world’s life forms
Do do do you, do do do do
but do you wonder how
matter forms something strange
when there’s a chemical change?
Where did these atoms come from? They were fused in stars
Light elements combine releasing light from afar
Fusion in the sun, creates Helium
I guess what I be saying is you gotta use your reason
To open up your mind and see the cause of the seasons
-How do we know what’s true? The scientific method shows you
It’s just chemistry that you and me are made of these atoms
Atoms bond together to form molecules
Most of what’s surrounding me and you
Water, sugar, sand and you’ll find things undreamed of
So Argon, Neon, Xenon
There’s no need to overstate
‘Cause we are of course
This, of this, of this, we’re made: atoms
This is the first Veritasium science video. It addresses one of the most fundamental concepts in science: the idea that all things are made of atoms, tiny particles that are in perpetual motion. They attract each other when a little distance apart and repel when squeezed together.
This is a must-see, from Citizens Against Government Waste. Regardless of your political leanings, you must admit this is a realistic scenario, some would say inevitable, unless the U.S. federal government takes a radically different approach to spending and borrowing real quick.
There is the trend, though history for things to get more complex, as culture, technologies, political structures and mechanisms get more complex. Therefore China “owning us” may be more a more complex, unclear and abstract scenario than historical instances of one nation conquering another, but a very real ownership nonetheless.
