All About Plasmas Trivia Quiz

Answer: False

Ionization of a substance occurs when neutrally charged atoms or molecules become charged by gaining or losing electrons. A sufficient amount of energy imparted to a gas, such as by intense heat or voltage, will cause ionization. This addition of energy excites the electrons to the point that they are freed from the nuclei of the gas atoms or molecules. The result is that there are now unbound electrons and positively charged nuclei (a.k.a. ions) mixed in with the gas.

Plasmas are indeed made up of ionized gas but ionization alone is insufficient to call something a plasma. Gasses may have a little bit of ionization without behaving differently from an unionized gas. Therefore, for a gas to be considered as having transitioned into at least a partial plasma, enough ionization needs to occur such that specific electromagnetic properties are present. These electromagnetic properties are required to distinguish a plasma from a gas. The degree of ionization which determines when a gas becomes a partial (a.k.a. weakly ionized) plasma will vary between different types of plasma, and may be as little as 0.0001%.

Answer: True

When enough atoms or molecules in a gas are ionized, the mass of gas and ionized particles has specific electromagnetic properties which normal gasses do not have. When these properties are present, the mass is at least partially or weakly in a different state of matter.

Just as solids, liquids and gasses all have properties which distinguish each state from the others, plasmas have distinguishing properties. Unfortunately for educational purposes, the transition from gas to plasma is often more of a continuum than an abrupt change. Except at extreme energies, such as in stars, we are often dealing with partial (weakly ionized) plasmas.

Answer: True

Fusion in the core of the sun creates a tremendous amount of heat and electromagnetic radiation. This energy ionizes the vast majority of the surrounding gas turning the sun into a giant plasma. The sun contains over 98% of the mass in our solar system and this dominance of mass is also the case for most stars with their planetary systems. Much of the interstellar matter is also ionized.

In fact, when you add up all the visible matter, over 99% is estimated to be in the plasma state. Matter in planets and asteroids exists mostly in the solid or gaseous state but these bodies make up only a tiny fraction of the matter in the universe. (Of course exotic states of matter, such as dark matter, are another matter entirely.)

Answer: False

Gasses are indeed generally poor conductors of electricity. One of the electromagnetic properties that distinguishes plasmas from gasses is that plasmas are very good conductors of electricity. This is because the free electrons and ions are charged particles and electricity is the flow of electrical charge.

The availability of charged particles allows electrical current to flow whether in a plasma, metal or other conducting substance. A partial plasma achieves an electrical conductivity of about half its possible maximum with only about 0.1% ionization while 1% ionization approaches the conductivity of a fully ionized plasma.

Answer: True

The existence of the solar wind was first proposed by astrophysicist Eugene Parker in 1957. It is because of his work that NASA's Parker Solar Probe mission was so named.

Parker theorized the superheated corona of the sun could be emitting charged particles at an extremely high speed. In the sun's corona, plasma is continually heated with temperatures reaching a blistering 2 million degrees Celsius (3.6 million Fahrenheit). At these temperatures, the plasma becomes so energized that the sun's gravity can no longer hold it so it hurls into space as the solar wind.

The presence of the solar wind has been measured directly by spacecraft. Solar wind particles are very diffuse but highly energetic with velocities averaging 400 km/sec (900,000 mi/hr). The solar wind has a magnetic field, which gasses do not, confirming an electromagnetic plasma property.

Answer: False

Auroras are generated by solar wind but not by the regular constant variety. In addition to the regular radiation of solar wind, bursts of plasma are ejected by the sun and are called coronal mass ejections (CMEs). CMEs are still part of the solar wind but are faster and extra energized. They are often referred to "solar storms" in the popular media. CMEs are sometimes, but not always, associated with solar flares.

When the solar wind interacts with the Earth's magnetosphere (the region of space surrounding Earth where the dominant magnetic field is the magnetic field of Earth), the charged particles are directed toward the poles. Most of the solar wind is, in fact, deflected around the Earth. However, CME impacts are of sufficient energy that plasma particles can penetrate the magnetosphere and continue downward into the Earth's atmosphere. These highly energic CME particles then collide with air molecules in the Earth's atmosphere.

The collisions between CME particles and atmospheric molecules send the atmospheric molecules into higher energy states which are unstable. All atoms and molecules, including atmospheric molecules such as oxygen and nitrogen, release energy in characteristic amounts when they drop from a higher energy state to a lower one. These releases of energy by atoms and molecules generate specific colors of light (when the energy released corresponds to energy in the visible spectrum of light). In the case of the aurora, molecular oxygen typically releases energy in a specific shade of green which is why this color is common in auroras.

Answer: True

Superheating, as occurs in the sun, is one way to ionize gas and create a plasma. Another way to generate a plasma is by applying a high voltage. We can do this by filling a glass tube that has metal contacts at the ends with a small amount of a gas at low pressure. We then apply a high voltage across the ends of the tube. This will ionize a significant proportion of the gas. When there is sufficient ionization, current can flow within the tube as negatively charged electrons are attracted to the positive terminal and positively charged ions are attracted to the negative terminal. The flow of current indicates that we have generated a partial plasma within the tube.

Other atoms or molecules of the gas are energized by collisions with moving ions. The energized atoms or molecules are unstable. When they drop down to their normal energy level, they emit a characteristic color of light (when the energy corresponds to the visible spectrum). This process is similar to what happens when solar wind particles collide with atmospheric molecules to generate auroras. In the case of neon, the color of the light emitted is a brilliant orange. Thus, neon lights work because a partial plasma is generated which enables current to flow. The flowing ionized particles then excite atoms of neon to emit light.

Answer: True

Interestingly, plasma is involved in both the cause and effect of lightning. The most common conditions that create lightning arise from super-cooled small water droplets, soft hail (graupel) and ice crystals which move around in clouds and become ionized. (These are solids and liquids being ionized, not gasses.) As positive and negative charges accumulate in separate regions in the atmosphere, large charge differences can develop between two regions in the air or between the air and the ground.

When the charge difference reaches a critical level, which is dependent upon atmospheric conditions, the air in between these areas becomes significantly ionized. This is called a plasma channel. With the availability of charged particles in the plasma channel, current can flow and lightning occurs.

Lightning is a high energy electrostatic discharge, that is, the abrupt flow of current. Most of the energy is released in pulses about one-hundred-millionth of a second long. A typical lightning bolt has a peak temperature greater than 25,000 degrees Celsius (45,000 Fahrenheit) - around five times hotter than the surface of the sun! At this temperature, many of the air molecules in the bolt are ionized. Therefore, the availability of a plasma channel creates the conditions in which the lightning can occur. The discharge then ionizes much of the air in the bolt forming a more ionized plasma.

Answer: True

The ionosphere is the ionized part of the upper atmosphere of Earth, from about 48 km (30 mi) to 965 km (600 mi) above sea level. It is ionized by solar radiation, especially ultraviolet, and has electromagnetic plasma properties. Although there is less ionization of the upper atmosphere at night, a partial plasma is still present surrounding the Earth.

The ionosphere was discovered in the early 1900s when it was found that radio waves traveled around with the Earth's curvature by bouncing off the upper atmosphere. If radio waves have frequencies near or below the plasma frequency (the frequency at which the electrons in the plasma naturally oscillate relative to the ions), they cannot travel through the partial plasma of the ionosphere and thus do not escape into space. Instead, they are either reflected or absorbed. This reflection or absorption of radio waves is a key electromagnetic property of plasmas which gasses do not have.

Answer: Whether or not fire is a partial plasma depends on the temperature of the flame

Flames have different temperatures depending upon what is burning. A flame only becomes ionized enough to be considered a partial plasma if it gets hot enough that the electromagnetic properties of a plasma become apparent. Flames in our everyday lives are nowhere near the temperatures of the sun or lightning and are partially ionized at best.

A common flame, such as from a candle, is a hot (1500 degrees Celsius or 2700 Fahrenheit), very lightly ionized gas which also contains some tiny solid fragments of the material being burned called soot. A flame is mostly a heated volume of air in which a small number of electrons have broken free from their nuclei. Some ionization has taken place but not enough for plasma properties to occur. As the temperature gets hotter, such as in an oxy-acetylene torch (3500 degrees Celsius or 6300 Fahrenheit), enough electrons become freed that the flame is considered to be a partial plasma.

How do flames produce light? The light produced by a low temperature flame mostly comes from incandescence. The incandescence is from the tiny particles of soot which glow similarly to an incandescent light bulb. As a flame gets hotter, more of the soot is burned off and there is light which is produced by air molecules dropping from higher energy states back to their ground state as in neon lights and auroras.