INSIDE THE SPHERE BY JOHN SODEAU

ILLUSTRATED BY NICHOLAS McGUIRE

A SET OF SCIENCE FACT AND FACTION BOOKS ON THE ENVIRONMENT

FOR TRANSITION YEAR STUDENTS

Chlorofluorocarbons (CFCs)

In the 1920s because of methyl chloride or sulfur dioxide or ammonia leakage from refrigerators, three American corporations,

Frigidaire, General Motors and DuPont began a search for a less dangerous method of refrigeration. In 1928, Thomas Midgley,

Jr. invented a "miracle compound" called Freon. In fact it proved to be one of a set of inert, colourless, odourless, non-

flammable, and non-corrosive gases with appropriate vapour properties. However it was the unreactivity of the CFCs that al-

lowed them to float up to the stratosphere over time after the new technology refrigerators had been dumped. Nothing destroyed

the CFCs in the lower layer of the atmosphere. Once in the stratosphere they could rise to the top of the ozone layer and become

photolysed by the sun. (Here the ozone filter from high energy UV radiation was simply not available). The CFCs then could

break down to form reactive chlorine atoms, which themselves could attack the ozone around them.

The way that we think of the breakdown of any molecule by sunlight is by considering the sun’s radiation as consisting of dis-

tinct “bullets” that we term photons. Every photon has an individual wavelength (or colour) associated with it and the shorter the

wavelength (the blue and ultraviolet) the greater the energy they possess. Red photons have longer wavelengths and therefore

less energy: they have a warming effect on us rather than causing our chemical bonds to break like the UV ones can promote.

This is the heart of the CFC problem inside the Sphere. If the Anthro encounter ozone “up close and personal” then the reactivi-

ty of the ozone harms them directly. If, in retaliation they try to destroy ALL the ozone by using chlorine as a weapon, then their

essential atmospheric filter from harmful radiation would be destroyed. Again they would suffer but this time by photolysis with

high energy UV radiation from the sun. So the Goldilocks solution is required here: not too much and not too little, it has to be

just right!

Mylar: a strong polyester film, trademarked

by DuPont in 1954. The name does not

mean anything….. they just liked the sound.

What proportion of the surface

of Planet Earth is covered by

water?

The Sphere of Atmos was huge and sat quite still. It ap-peared to be solid but was actually quite flexible be-cause it was made out of a strong material that was a lot like Mylar foil. So from the outside the Sphere appeared like a silver-black party balloon filled with gas.

Inside the Sphere it was all very different. In the lower part there was some land and lots of ocean water but the space above them seemed to be empty. That is except for the white, floating, watering-carriers that would become grey-black just before leaking. Not only were they beau-tiful but they also transported moisture released by the oceans over to the land. And this rainwater helped to make the plants grow.

The Sphere This inner surface did not all move to one shade are.

The Sphere

Write an equation to show how

the speed of light connects the

frequency associated with a

photon to its wavelength.

The Fo-tons were all brilliantly bright and could move very fast indeed. They were difficult to see individual-ly but they all left a distinctive trail.

There were seven types altogether. Some were short and pointed like darts. They were almost transparent or violet or blue. They also moved the fastest and were seen the least. The yellow and green types moved more slowly but there were lots of them about.

Finally there were two big, disc-shaped red and or-ange ones that moved slowest of all.

T. It appeared to be solid but was actu-ally quite flexible and made out of a strong netting material. So from the

Fo-Ton Trails

Fo-Tons

What is the name of the radia-

tion that causes sunburn to

harm skin and plants?

Soon Midge had caught a large selection of the Fo-Ton flying machines. Then he carefully tied a CFC to each one making sure not to cover the circular engines. After that he took them in a large bag to the place where the captured Oz-1s were being held.

The Chief Scientist thought he was wasting their time: “This will never work?” she said while laughing. “It’s risky not crazy and if you don’t try then of course it won’t work” snapped Midge back at her.

So they tried, and you know what… it worked. At least, every time they saddled a CFC to a light blue or purple Fo-Ton and fired it straight at an Oz-1, it was split into two parts.

The War was as good as won!

The CFC Weapon

Write two chemical equations to

show how chlorine atoms react with

ozone and then how the chlorine-

containing product reacts with oxy-

gen atoms. What is the net reaction

you get by adding these two reac-

tions together?

Midge knew that not all of the Fo-Ton machines were the same: “The short pointed ones that are almost transparent or violet al-ways get their Oz-1 target when they are saddled with a CFC.” he said to himself. “But the big, round red and orange ones never do. I need to do some more careful tests to see what’s really going on here. I know it’s not because the CFCs make the tri-ballz cold be-cause the temperature does not change when I fire them in.” But he was too tired that night to do any more work and he really missed his family and he cried himself to sleep.

Next day he felt much better and he put some Oz-1s into a wire mesh cage. Then he fired every colour of Fo-Ton in. There was lots of activity: each tri-ball split into an Oxy di-ball and also a uni-ball but soon they joined together to make the tri-ball back again.

Strangely, none of the Fo-tons emerged from the other side of the cage. They all appeared to have been destroyed in the break-up and make-up process.

High energy Fo-Tons

Captured Oz-1s

What reaction is in common be-

tween atmospheric ozone chemistry

that occurs with (PEQ17) and , sec-

ondly, without chlorine atoms

(PEQ16) being present?

When Midge saddled CFCs to the fast moving, dart-like Fo-Tons that were almost invisible or violet, things were very different. “The break-up’s the same but there’s no make-up” he exclaimed “And, if you look, a small amount of a green gas, that smells just like CLOX is given off.”

After a while, when most of the Oz-1s had been destroyed, the Fo-Tons started appearing from the other side of the cage. Several of them actual-ly hit Midge’s pet, Bakenko. “MIAUL” it screamed out in pain because great burns appeared where the Fo-Tons had touched!

“Somehow the Oz-1s must be saving us from the Fo-Ton darts coming in through the hole in the Sphere. So when all the tri-ballz are destroyed by the CFCs riding on the Fo-Tons, the sharp ones go through gaps in the Oz-1 shield” he said out loud “but if the CFCs aren’t there, then the Oz-1s protect us from them burning our skin. Instead the Oz-1s use the burn-ing energy to change into Oxy di-ballz and uni-ballz. Then they can link back together again”. Midge had finally discovered the regeneration games…..something the Anthro could not play themselves.

OUCH!

Book 1

PEQ11: NO + O3→ NO2 + O2 ; 2NO + O2 → 2NO2

PEQ12: The boundary is called the tropopause and is on average 9 km in altitude at the poles and 17 km at the Equator. The value depends on the temperature of the atmosphere beneath it.

PEQ13: Sodium hypochlorite. Na+OCl- + 2HCl →Cl2 + Na+Cl- + H2O

PEQ14: CF2Cl2 known as Freon-12 is one of the best known. Freon-11, CFCl3 , is another.

PEQ15: Ultraviolet or UV.

PEQ16: O3 + h→ O2 + O; O2 + h→ O + O; O3 + O→ O2 + O2. (Where his a photon PEQ17: O3 + Cl→ O2 + ClO; O + ClO→ Cl + O2; O3 + O→ O2 + O2.

PEQ18: O3 + O → O2 + O2. This reaction is key to stratospheric ozone loss because it is cata-lytically accelerated by the presence of chlorine atoms. Note how both Cl and ClO are gained and lost in the first two reactions of PEQ17.

PEQ19: (i) Highly dependent on the presence of other pollutants such as NO and can range from 10-500 parts per billion volume; (ii) Depends upon altitude but the maximum is about 10-12 ppmv

PEQ20: The Greenhouse Effect. More on this topic in Book 2, The Meltwater Flood.