National ResearchFoundation

South African Agency for Scienceand Technology Advancement

NRF SAASTAsciencescience& technology& technologyDepartment:Science and TechnologyREPUBLIC OF SOUTH AFRICA

EasyScience is produced by the South African Agency for Scienceand Technology Advancement (SAASTA), a business unit of theNational Research Foundation. SAASTA’s mission is to promotethe public's understanding, appreciation and engagement with

science and technology among all South Africans.

Visit the website: www.saasta.ac.za for more information

27

During the cold days of thewinter, I started thinkingabout different sources ofenergy and how to savethis energy. What willhappen to the world ifthese sources of energywould run out? Are thereother sources of energy?How will we stay warm?

Option 1: Crude oilWhat is it?

One of our biggest sources of energy is crude oil – asmelly, black liquid found in underground areas. It isa substance formed by tiny sea plants and animalsthat died and were buried on the ocean floor. Overmillions of years, the remains were buried deeper

and deeper by layers of silt and sand. The enormousheat and pressure turned them into oil and gas.Today, we drill down through all these layers to reach

the rock formations that contain oil and gas deposits.

How do we get it?After crude oil is pumped from the ground, it is sent to a

refinery. At the refinery, crude oil is separated into differentuseful forms. The process used is called fractional distillation.During this process, the crude oil is exposed to different

temperatures, which lead to various substances beingtapped off. This happens because crude oil consists

of elements that all boil at different temperatures.

Option 2:Hydrogen and FuelCell TechnologyJohn Bockris suggested in 1970that we could use hydrogen as anenergy carrier. Electricity is the mostwell-known energy carrier. We useelectricity to move the energy in coal,uranium, and other energy sourcesfrom power plants to homes andbusinesses. Hydrogen stores energyfrom other sources such as biomass(like plants), the sun and wind; anddelivers this energy in a usable formto fuel cars and planes, power forbuildings and electronic devices,and heat for our homes. Hydrogentogether with a fuel cell converts the

energy into electricity. However, thefuel cells are very expensive, whichis one of the major obstacles in itsdevelopment. Most of the hydrogen onearth is bonded to oxygen to form water.So, how and where do we get molecularhydrogen (H2)? Here are a fewproduction methods:

RenewableEnergy SourcesElectrolysis can also be done usingthe electric current from renewablesources to convert biomass or separatewater to hydrogen. During this process,a wind turbine is used to produceelectricity from the wind, and photovoltaic(solar electric) systems are used to produceelectricity from solar resources. This renewablyproduced electricity is then used in anelectrolyser, a device that uses electricityto split water into hydrogenand oxygen.

Biological productionIn the late 1900s it was discovered that if algae is deprived of sulphur, it will not produce O2 during photosynthesis, but hydrogen. Biological hydrogen can beproduced in bioreactors. This process involves bacteria feeding onhydrocarbons (molecules that contain hydrogen and carbon) andexcreting hydrogen and CO2. The CO2 can be removed and usedsuccessfully, leaving hydrogen gas.

Electrolysis of waterWhen an electric current is passed through water it can break up into oxygen and hydrogen. Using this electrolysisprocess under high pressure ensures that hydrogen is compressed as part of the process and therefore does not require an external hydrogen compressor.

Then what?If hydrogen is to be used as fuel for a car, it needsto be pressurized or liquefied to provide enoughenergy. Liquid hydrogen storage tanks must alsobe well insulated to minimize boil off. Hydrogenboils at a temperature of -253˚C. Hydrogen is a very explosive gas, it doesn't have a distinct odour and leaks cannot be detectedby smell. This makes it very dangerous inenclosed areas. But, not to worry! Safety

codes and standards have ensuredthat the public will be able touse hydrogen technologies in everyday life with the samelevel of safety and comfortas with today's fossil fuels.

Why usehydrogen?As an energy carrier,hydrogen can be

produced safely and abundantly

from renewable energyresources. This will help todecrease dependence of

nations on others for fuels(crude oil) and also reduce the

greeenhouse gas emmissionsthat causes global warming.

Energy conversion devices that use hydrogen are highly

efficient and produce very little or no harmful emissions with

by-products being water and heat.

MiniMag26

All these substances are then usedto make gasoline, diesel fuel andother petroleum products. Most ofthe petroleum products are used toproduce energy, but other productsmade from petroleum includecrayons, dishwashing liquids,deodorant, tyres, ammonia, heartvalves and even bubble gum.Bet you never knew that!!

What else do we do with it?Products made from oil help usdo a lot of things. We use themto power airplanes, cars, trucks,heat our houses and to makemedicine and plastics. Eventhough petroleum products makelife easier, it is not all good:

ee

Since 1990, fuels have been changed to produce lesspollution. New cars have air pollution equipmentinstalled, but now they cost a lot more.

ee

Drilling for oil disturbs land and ocean habitats. If oilis spilled into rivers and oceans, it can harm wildlife.

ee

An oil refinery is a factory where crude oil is distilledand cracked into petroleum products. This leads todifferent pollutants escaping into the air.Governments monitor refineries and factories toensure that they meet the regulated standards.

ee

We all know that petrol and diesel give off carbondioxide (CO2), a greenhouse gas that is linked toglobal warming. In 2006, the amount of sulphurcontained in diesel was reduced, to ensurecleaner burning and fewer emissions of CO2.

Wow! Crude oil is an awesome substance,but what happens to our environment whenwe use it, and what happens if we use it all?

by Helene Share

Aaaah!The holiday is

over and everythingis back to normal. I had

a wonderful holiday. Eventhough it was very cold, I

kept myself warm with someexperiments that work very well, especially

during the winter. But before weget to that.........

energyFreezing

Kylethinksofenergy

FreezingKyle

thinksof

Did youknow?

Other products madefrom petroleum include: Ink, crayons, dishwashing

liquids, deodorant, eyeglasses,CDs and DVDs, tyres,

ammonia, heart valves

Makelightning

Method1. Push the

thumbtackthrough themiddle of thepie pan, fromthe bottom.

2. Push theeraser end ofthe pencil intothe thumbtack.

3. Put thestyrofoam plateupside-downon a table.

4. Quickly rub theplate with woolfor a couple ofminutes.

5. Pick up thealuminium pie panusing the pencil as ahandle and place iton top of the chargedstyrofoam plate.

6. Touch the aluminiumpie pan with yourfinger. You should feel a shock.

7. Once you have felt the shock, tryturning the lights off before youtouch the pan again.

Why does it form a spark? It's all aboutstatic electricity! The electrons in yourfinger are attracted to the protons inthe aluminium pie pan, resultingin a mini lightning bolt.

You will need:3 Aluminium pie can

3 woollen jersey

3 styrofoam plate

3 pencil with neweraser at the back

3 thumbtackBend WaterRub a comb fast against your jersey.Hold the comb near a thin stream of water.The charged comb attracts the water.

Why?By rubbing the comb, you're

covering it with negativecharges called electrons.

The electrons areattracted to the positive

charges (protons) inthe water. Unlike

charges attract!

DIY DIY StaticStatic

ElectricityElectricity

So, here are some of those simple, winter

experiments I told you about.

National ResearchFoundation

South African Agency for Scienceand Technology Advancement

NRF SAASTAsciencescience& technology& technologyDepartment:Science and TechnologyREPUBLIC OF SOUTH AFRICA

MiniMag28