Photo
March 16, 2011
35 notes
Let’s consider a nuclear reaction with uranium-235 as the fuel. Inside the fuel rods, a neutron with the appropriate energy collides with a uranium-235 atom and is incorporated into this atom’s nucleus. The uranium atom now has an extra neutron and becomes uranium-236. However, uranium-236 is unstable and immediately decays to two smaller atoms—the fission products. Many different fission products are made, such as cesium-133, iodine-135, etc. Wikipedia has a nice entry explaining the fission product yield for uranium-235. Breaking atomic bonds also releases energy in the form of heat. The purpose of a nuclear power plant is to capture this heat and turn it into electricity. This is analogous to a fossil fuel power plant, where chemical bonds are broken to release heat. When the uranium-236 decays, extra neutrons (and some other things) are also released. These are called prompt neutrons because they come directly from the fission reaction. (They’re produced promptly.) These neutrons collide with more uranium-235 and the reaction continues. Fission products can also sit around for a while and then decay to produce neutrons, and these are called delayed neutrons. If neutrons are being produced, the fission reaction will continue, and the rate of reaction will be a function of the number of neutrons being produced.

Let’s consider a nuclear reaction with uranium-235 as the fuel. Inside the fuel rods, a neutron with the appropriate energy collides with a uranium-235 atom and is incorporated into this atom’s nucleus. The uranium atom now has an extra neutron and becomes uranium-236. However, uranium-236 is unstable and immediately decays to two smaller atoms—the fission products. Many different fission products are made, such as cesium-133, iodine-135, etc. Wikipedia has a nice entry explaining the fission product yield for uranium-235.

Breaking atomic bonds also releases energy in the form of heat. The purpose of a nuclear power plant is to capture this heat and turn it into electricity. This is analogous to a fossil fuel power plant, where chemical bonds are broken to release heat.

When the uranium-236 decays, extra neutrons (and some other things) are also released. These are called prompt neutrons because they come directly from the fission reaction. (They’re produced promptly.) These neutrons collide with more uranium-235 and the reaction continues. Fission products can also sit around for a while and then decay to produce neutrons, and these are called delayed neutrons. If neutrons are being produced, the fission reaction will continue, and the rate of reaction will be a function of the number of neutrons being produced.

Tags: science physics nuclear nuclear power japan nuclear fission uranium atom

Link
April 08, 2010
7 notes
Realistic scale of an atom

Click the link to see, as only the internet could show you, the relative size and spacing of protons and electrons. (Our Clear Science schematics are not “to scale.”)

The blue sphere represents a proton. Scroll to the right, and the green sphere is an electron.

Tags: science atom chemistry

Photo
April 08, 2010
3 notes
Protons and electrons are equal in an atom’s natural state. The atomic number tells how many protons an atom has. That determines its identity as one element or another. It will also have that many electrons in its orbitals, at least to start with. The number of electrons does not determine an atom’s identity. Rather, this determines how elements will react and bond with each other. Swapping and sharing electrons is how atoms interact. Water, which is not an element, is made up of hydrogen (Element 1) and oxygen (Element 8) sharing electrons. You probably already knew that.

Protons and electrons are equal in an atom’s natural state.

The atomic number tells how many protons an atom has. That determines its identity as one element or another. It will also have that many electrons in its orbitals, at least to start with.

The number of electrons does not determine an atom’s identity. Rather, this determines how elements will react and bond with each other.

Swapping and sharing electrons is how atoms interact. Water, which is not an element, is made up of hydrogen (Element 1) and oxygen (Element 8) sharing electrons. You probably already knew that.

Tags: science chemistry periodic table atom electrons

Video
April 07, 2010
12 notes

Noted physicist Venus Flytrap explains the atom Clear Science style

This is from the awesome television show WKRP in Cincinnati, which aired when the Clear Science staff were young boys and girls. Are we doing as good a job as Venus?

Tags: science atom WKRP

Photo
April 07, 2010
1 note
Last week we introduced our Far Too Simple Model Of An Atom© so we could talk about protons. A more complete view of the atom includes two other particles: neutrons, which hang out in the nucleus with protons, but don’t have + written on them electrons, which are smaller, have a - on them, and are in motion in the orbitals, rather than the nucleus PS You know which element this atom is. (answer)

Last week we introduced our Far Too Simple Model Of An Atom© so we could talk about protons.

A more complete view of the atom includes two other particles:

  • neutrons, which hang out in the nucleus with protons, but don’t have + written on them
  • electrons, which are smaller, have a - on them, and are in motion in the orbitals, rather than the nucleus

PS You know which element this atom is. (answer)

Tags: science chemistry atom element nucleus electrons

Text
March 31, 2010
3 notes

ἄτομος

or átomos, meaning “uncuttable.”

This is the Greek root of atom. Greek philosophers in the 5th century BCE got the idea that everything might be made up of tiny particles. These would be the smallest, indivisible unit of matter. (It was just an idea—they didn’t know for sure.)

They got this idea in ancient India even earlier, but we use the word chosen by the Greeks.

Now we know atoms exist and are cuttable (for instance, they’re made of protons). However, elements do not exist below the level of the atom. Cut up a gold atom and it won’t be gold anymore—it will just be the parts.

Tags: science atom