In the following article, a series of "snapshots" will provide you with a broad understanding of the most basic building block in the universe, the atom. You will have a chance to think about atoms in different ways. Because we cannot see an individual atom, or feel or taste one, or even isolate one–for many exist only in the company of other atoms, in what we call molecules–we must call upon our imaginations to do some work.
Imagining Atoms
Imagine drinking a glass of soda. The glass is made of atoms in a solid state. The soda is in a liquid state. The bubbles are composed of atoms of gas.. Everything is made of atoms, the building blocks of the entire universe. Each atom behaves in predictable ways under certain circumstances. Scientists are constantly discovering new atomic behaviors that will shape our futures.
Most people don’t think in terms of atoms. They think in terms of things like the sun, heat, radiation, blood, DNA and genes, lungs, electricity, water, computers. As Mission Specialists you must begin to see and think of everything in terms of atoms and molecules. In this way, you will be able to understand the space station and the energies of outer space in a new light, so to speak. You will also understand the changes that are taking place in the world around you in a new way.
Snapshot #1: A Brief History of Atoms
Scientists, and originally philosophers, sought to explain the natural world by seeking to understand the most basic building blocks in the universe.
| 2500 years ago, scientists were called philosophers. Sometime between 460 and- 370 BC, two Greek philosophers, Democritus and Leucippus, came to the conclusion that everything had to be made of small building blocks. All the other philosophers at that time thought that everything in the universe was made of fire, water, earth, or ether. Democritus and Leucippus dared to be different. They called their building blocks "atoms.". Their idea, however, sat unstudied/dormant for 2,300 years. | Around five hundred years ago, a Polish scientist and an Italian scientist, Copernicus and Galileo, gave birth to modern science. They provided evidence that the earth orbited the sun, an important step on the road to understanding atoms because it freed curious minds to think new ideas. Nevertheless, it still took another few centuries and many bright thinkers to shift the predominant scientific thinking from a universe of "fire, water, earth, and ether" to one of atoms and molecules. | In the last 150 years, modern scientific ideas came in floods, thanks to modern communications and advances in technology. In the early 1900’s, science had no borders. An international group of scientists shared their explorations in mathematics, electricity and magnetism, radioactivity, and light. Since that time, scientists have discovered the various components that comprise atoms: electrons, neutrons, protons, and even sub-atomic particles, such as quarks and gluons. |
Snapshot #2: Atoms Can Be Found in Various States or Phases
[No it doesn’t. It is a "snapshot."]
Solids. Put a hand on your desk. What is your desk made of? Wood? Metal? A solid! Within a solid, atoms bind with other atoms in tightly packed molecular structures that resemble a crystalline lattice. Can you feel the atoms’ constant vibrating motion? Of course not, but they are vibrating within their lattice-like structures.
Liquids. Place a drop of moisture from your mouth on the tip of your finger. This is a liquid. Atoms in the liquid state are not as tightly bound together as in solids. They slip and slide around each other. Heat the liquid and the atoms begin to collide violently. If heated to the boiling point, a liquid’s atoms move even farther away from one another and become a gas.
Gases. Wave your hand in front of your face. Can you feel the breeze on your skin? This breeze consists of gas molecules, primarily nitrogen and oxygen atoms bound together, hitting you in the face. These molecules move about randomly, constantly colliding with each other. Add energy in the form of heat and they bounce faster, creating what scientists call more pressure. Reduce the heat, or cool them down and they slow down. When forced into a balloon, the molecules try to escape. Gradually the gas molecules slip between the molecules of the balloon’s rubber, causing the balloon to deflate.
Plasma. Study an image of the sun. Deep inside this ball of flame, atoms are squeezed together under tremendous pressure and heat. The heat becomes so intense that atoms cannot retain their structure. The bonds between various individual atoms break down. Within each atom, electrons, protons, and atomic nuclei are so energized that they no longer bind to one another. A type of atomic particle, known as plasma, is created.
The sun is comprised of hydrogen, helium, and plasma. The hydrogen is nearly unrecognizable in its "ionized" state. An ionized atom is one that has either a deficiency or surplus of electrons. The hydrogen atoms in the sun’s core have all been ionized. This means that one electron has been removed, leaving behind only one proton in the nucleus of the atom. Helium in the sun’s core is also ionized, with two protons and two neutrons in its nucleus and a maximum of one electron.
Hydrogen and helium nuclei in the sun form the vast majority of the sun’s plasma. In the sun’s core, super-heated, atomic particles play nuclear tag. This process can be so unpredictable and so violent that huge amounts of electrical and magnetic energy can be released in gigantic storms called Coronal Mass Ejections (CMEs). Some of these storms hurtle atomic particles, gamma rays, X-rays, and many other types of electrical and magnetic energies out into space.
Snapshot #3: Feeling Atoms and Energy
The idea of atoms and energy are closely linked. Is it too big a leap for your imagination to begin to think that everything in our known universe has to do with atoms or parts of atoms? This includes the heat from the sun, the lightning from the sky, the explosion of a nuclear bomb, and the electricity in a light bulb.
Try this simple experiment.
Find a wooden pencil and hold it in your hands. Look at it carefully. You will see wood, paint, printing ink, graphite, metal, and rubber. Can you see the atoms? Certainly not!
Rub the painted wooden part of the pencil. What happens? The area you rubbed feels warmer. Why? As you rubbed the atoms of paint or wood, the electrons of the atoms on the outside of the pencil became agitated and so did the atoms in the skin molecules in the palm of your hand. You are adding energy, in the form of rubbing, to the atoms you are touching. Rubbing, or what is called "friction", causes an increase in the energy levels of the rubbed atoms’ electrons. The atoms soon begin to vibrate faster, causing nearby atoms to also become excited and vibrate faster. If you are quick enough, you might even be able to measure the temperature increase. If you touched a thermometer to these excited atoms, the atoms in the thermometer would start to vibrate at an energy level similar to the pencil atoms and would register the temperature of the pencil.
Energy spreads and changes form, but remember that it never disappears. When energy is added through the rubbing, the atoms vibrate faster. How much rubbing would it take to light the pencil on fire? Lots! You would need enough energy to reach a temperature that would break the bonds of the molecules in the pencil. This level of heat is called the molecule’s combustion point. All molecules have a combustion point. The heat in the core of the sun far exceeds the combustion point of all chemicals, which is why there is nothing but solar plasma in the core of the sun.
Snapshot #4: Build a Model of an Atom–A Thought Experiment
First consider several facts about atoms and let a picture form in your imagination.
• Every atom is built with the same identical atomic particles, except one. Please see the next "fact." Electrons carry a negative charge. Neutrons have no electrical charge, while protons carry a positive charge. Atoms as different as hydrogen and silver simply differ in the quantity of their atomic particles.
• The hydrogen atom has one proton and one electron and no neutrons. It is the simplest atom.
• Every atom has a nucleus.
• The nucleus of every atom, except hydrogen, is made of at least one neutron and one proton.
• The nucleus of every atom represents at least 99.945% of the atom’s mass.
• The diameter of an atom’s nucleus is 1/100,000 of its entire diameter.
• Electrons are 1/1836 the size of a proton.
• Electrons circle the nucleus in what was originally thought to be an "orbit," but what has most recently been called an "energy level" or an "electron cloud."
• The simplest atom has one electron (hydrogen); the most complex, naturally-occurring atom has 92 (uranium).
• No matter how many electrons are in an atom, they never bump into each other!
• Don’t confuse protons and photons. "Protons" are one of several particles in an atom. "Photons" are electromagnetic energy given off by electrons after they become energized...
Procedure for the Thought Experiment:
Given the facts that you just read about atoms, it might be fun to create a model of an atom that everyone could actually see. It would help to point out more atomic mysteries. But where would you begin?
First, why don’t we consider the dimensions of the atomic particles and the atom as a whole? The nucleus has 99.9+% of the atom’s mass, but only is 1/100,000 of its diameter! What objects could we use to represent the protons and neutrons in an atom’s nucleus? We need an objects that areis large enough to see from a distance, but small enough to keep our model at a reasonable size. What if we start our atomic model with a small, steel ball bearing? Let’s use one about 1/8 inch (3 mm) in diameter. This ball bearing will represent a singleour proton or neutron.
What atom should we create? If we created an oxygen atom, we would need 16 ball bearings: 8 protons and 8 neutrons. Let’s start with something simpler, such as hydrogen. It has only one proton, no neutrons, and one electron. All atoms start with as many protons as electrons. If we want to create a different atom, we can always add more atomic particles to our model later.
Now we need a place to build our model. What do you think? Where should we go? How about in a classroom? The gymnasium? Your school’s parking lot? Let’s go somewhere exciting. How about the Superdome Stadium in New Orleans? We’ll start big and see what happens. Place your proton ball-bearing on the exact center of the fifty-yard-line. We must do some simple math.
3 mm = 1 / 100,000 of total diameter of hydrogen
What is the total diameter of a hydrogen atom?
3 mm x 100,000 = 300,000 mm
300,000 mm/ 1,000 mm = 300 meters = 274.32328.04 yards
Our hydrogen atom, with a 3mm nucleus, is more than 2.743.25 football fields in diameter!
Since the hydrogen atom has one proton, it must have one electron. So where is that electron? Since it’s 1836 times smaller than the ball bearing, we cannot see it with our naked eye. We do know that it is somewhere around 1560 meters from the fifty-yard line! That puts it in "orbit" above the roof of the Superdome. Maybe we should have used a smaller ball bearing!
Hopefully your imagination has gotten the idea. Now it can carry you into some of the deeper mysteries of the atom.
Snapshot #5: Atomic Smallness
How small is a real atom? Keeping the Superdome in mind, consider that one hydrogen atom is approximately 5 x 10-8 mm in diameter. The proton is 1/100,000th of that. And the electron? 1/1836th of the proton. Truly tiny!
The space between the two periods inside these brackets [ .. ] is approximately 2 mm in length. It would take almost 40 million hydrogen atoms to make a line as long as the space between the two periods. Imagine forty million Superdomes with nuclei the size of a ball bearing!
Snapshot #6: Electron Clouds and Vacuums
Thinking back to the Superdome atomic model, remember that there is literally nothing between the proton and the electron orbiting over 150 meters away. In 1907, a scientist named Dr. Ernest Rutherford conducted an experiment. In a metal box, he placed a piece of radioactive material on one side of a metal plate with a small hole in it. On the other side of the metal plate he suspended a very thin strip of gold foil so that any radioactivity traveling through the hole would hit the foil. He lined the inside of the metal box with photographic paper that would record traces of radioactive collisions. The photographic paper revealed that some of the radioactivity careened off the gold foil at different angles, while some of it passed straight through. He concluded that there were "holes" in gold atoms. He also provided the first evidence that atoms have nuclei, a novel idea at the time.
Rutherford discovered that there is a vacuum between the nucleus of a gold atom and its electrons. The same holds true for atoms of hydrogen. What’s confusing about the Superdome model of the atom is that the space between the proton ball bearing and the electron 150 meters away is filled with air. You must keep in mind that this would actually be a vacuum in a real hydrogen atom. Vacuums do not have air. They literally have nothing in them.
Snapshot 7: Atoms and Magnetic Fields
There is a basic principle connecting electricity to magnetism. Electricity and magnetism are two aspects of a single electromagnetic force. Moving electric charges produce magnetic forces, and moving magnets produce electric forces. Electricity is the movement of electrons from one atom to another in a constant flow.
At the atomic level, electrons create a magnetic field as they spin about the atom’s nucleus. Keeping this in mind, consider this. When you touch something, your brain tells you whether it is soft or hard, rough or smooth. The reality is that the magnetic fields of the electrons in your skin’s atoms are actually rubbing against the magnetic fields of the touched object’s atoms. These magnetic fields are repelling each other. You really never touch anything!
You and your friends are nothing but tiny atoms joined in extremely complex molecules that contain vacuums, electrons, protons, neutrons, and magnetic fields! On the atomic level, you are just like trees and pencils!
Magnetic fields surround everything. Some purported inventions claim to help human bodies realign their magnetic fields for better health. The earth and magnets have strong magnetic fields. The difference between humans, the earth, and a magnet lies in the types of atoms and the molecular structure in which the atoms are arranged. Molecules in human bodies comprised of carbon, oxygen, and hydrogen are very poor at forming magnetic fields. Iron atoms are great at lining up their electrons, in what is called "domains," to form a magnetic field. This is what happens in the earth’s core.
Certain elements, when organized in particular lattices, have atomic properties that make their electrons’ magnetic fields stronger. Rare elements, such as those in magnetite, provide material for the types of magnets used around us everyday. Hard drives, television sets, and stereo speakers all rely on magnets to work. There is a great deal of magnetic activity on the sun. Atoms are stripped of their electrons, which then move around with other electrons at high speeds, creating huge magnetic fields.
Snapshot #8: Molecules
Your Superdome-sized hydrogen atom can help you get a clearer picture of molecules. It is quite possible that you already knew that the chemical symbol for water is H2O. But have you ever considered what that symbol means at the atomic level? It means that 2 atoms of hydrogen (H) are bonded to one atom of oxygen (O).
A water molecule would consist of three Superdome-sized atoms sharing electrons. The atoms have formed what chemists call a bond. The bond is due to the unique characteristics of the oxygen and hydrogen atoms that are more stable in this configuration than they were in their original states. The three atoms are "molecularly" happy. The molecular formula for water is: 2 atoms of H plus 1 atom of O = 1 molecule of H2O.
In the space station, electricity flows through water to which has been added a solvent, or chemical compound. The mixture conducts electricity and becomes a part of the electrical circuit. Two conducting rods are suspended in the water. The electrical charge flowing through the water provides enough energy to break the bonds of the water molecules. Hydrogen is attracted to one pole and the oxygen to the other. The oxygen is stored in a tank and used to replenish the air the astronauts breathe. The hydrogen, which is very dangerous and flammable, is discarded into space.
Snapshot # 9: All Things Nuclear Start with Atoms
In 1906, Albert Einstein made a giant discovery. His imagination, knowledge, and observations led him to believe that energy and mass were the same thing. If they were different, it was only in their order of magnitude. In other words, a small amount of mass (a very few atoms grouped together) is equal to a huge amount of energy. Atoms are actually energy in disguise! Einstein published a paper stating that in order to find the potential energy of a cluster of atoms, you multiply the mass of the atoms by the speed of light (186,000 miles per second) squared. Since the time these ideas were first published, scientists have conducted experiments proving that Einstein’s theory is true. You can see proof of E=mc2 in nuclear reactions such as those that take place inside a nuclear power plant or inside the sun.
Nuclear reactions that are strong enough to involve the energy and mass exchange described in Einstein’s formula, release their energy in the form of electromagnetism. Like the radioactive particles that shot through Dr. Rutherford’s gold foil, gamma rays, X-rays, and ionized atomic particles from the sun and within nuclear power plants are able to penetrate the aluminum walls of the space station and the skin of the astronauts. These forms of ionizing radiation can, if intense enough, interrupt the electricity produced in the space station’s solar cells and flowing through the wires in the space station. They can also cause serious damage to the atomic structure with the cells and DNA of the astronauts’ bodies.
Snapshot #10: Atoms and Fire
When atoms join together to form molecules, energy is required to create bonds between the atoms. If these atoms break apart in the future, they will release this energy back into the system. Energy can cause atoms and molecules to become more excited and vibrate more. This energy can be felt in the form of heat. Energy may also be emitted in the form of electromagnetic energy. Gamma rays, X-rays, infrared rays, microwaves, and visible light are all forms of electromagnetic energy that form a spectrum of different wavelengths and intensities. Electromagnetic energy is emitted from atoms and molecules that need to release energy.
Consider the light bulb. When electrical energy is added to the atoms in the light bulb’s filament, this energy is transformed. The atoms of the filament have stable bonds, so most of the energy is emitted in the form of light waves and heat, or infrared energy. Objects in a dark room do not emit visible light waves because they are in a stable state and do not have excess energy to cause them to emit light. When the light bulb is turned on, the light waves from the filament travel to atoms in the surface of objects in the room, adding energy to their systems. This excess energy is again transformed, causing those atoms to give off visible light waves. When energized, most atoms emit visible light waves at frequencies that we perceive as colors.
Imagine a log on fire. What is fire? Energy in the form of heat and light. This energy was originally "stored" in the bonds between the atoms when they formed into molecules. If you expose a molecule to enough energy, the individual atom’s electrons begin to energize and leap to higher energy levels. This behavior breaks bonds and causes molecules to break down into component atoms. When the atoms return to a more stable energy level, the excess energy is emitted as electromagnetic waves, including visible light. The photons of light are coming from the excited electrons in the flames.
Wood is comprised mostly of carbon, hydrogen, and oxygen arranged in hundreds of various molecular structures. Fire changes the molecular structure of the wood. When wood burns, the bonds between the three atoms are broken. Some of the hydrogen and oxygen atoms are released as water vapor, some as gaseous oxygen and hydrogen, and some are transformed to energy. When the gases disperse into the atmosphere, you feel "heat". The carbon atoms remain in the form of ashes.
What levels of energy might electrons reach when hit by photons of gamma rays or X-rays? What might happen to the molecular structures of atoms that are hit by these intense electromagnetic energies? Gamma rays and X-rays can strip electrons from the atoms they hit. Therefore, they are referred to as ionizing radiation.
Snapshot 11: Atoms and Molecules on Space Station Alpha
Now you know more about the reality of atoms. You can picture atoms in your mind’s eye. This makes it far easier to imagine such things as:
• Electricity - The jumping of electrons from one atom to another down a copper wire at the speed of light.
• The alignment of enough atoms and electrons in a molecular crystal solid to create magnetism and a magnetic field.
• The process of breathing — An oxygen molecule moves through the lining of an astronaut’s lungs, journeys through veins attached to hemoglobin, joins with a carbon atom inside a muscle cell to form carbon dioxide, travels back through the blood stream, and is exhaled into the space station.
• Photovoltaic aArrays and eElectricity— Light photons from the sun collide with the silicon atoms in the station’s solar arrays, causing the release of electrons and the flow of electricity that keeps the astronauts alive.
• Radiation sickness — Caused by interaction of X-rays, photons, and radioactive protons from the sun with the sensitive molecular structures in the astronauts’ cells.
Space Station Alpha depends upon its scientists’ and Mission Specialists’ knowledge of atoms. In the Mission Specialist’s training manual, you will encounter atoms in every article. The atomic particles given off during a solar storm have implications for space weather, radiation health, life support, and the space station’s power.
