Does stainless steel get rid of garlic smells?

This morning a tweet caught my eye

OK a chemistry question for @FunSizeSuze stainless steel seems to get rid of garlic odour from hands, but how? http://t.co/aFPDOJQ48q
— Dr Suzie Sheehy (@suziesheehy) October 15, 2013

Speculation followed.

@suziesheehy Good question! From memory, garlic odour comes from allyl methyl sulfides. Presumably the sulfide part reacts with a component
— Dr Suze Kundu (@FunSizeSuze) October 15, 2013

But before we get to the 'how' question maybe we should figure our if there is any truth in the anecdotes.

So how about an experiment? And I'll be needing your help for this one.

You'll need

• A clove of garlic.
• A knife.
• A timer.
• A wooden spoon and a stainless steel table spoon of about the same size.

What to do
1. Wash and dry your hands (so they don't smell of anything to start with).

2. Cut the clove of garlic in half (don't peel it, that way your fingers won't pick up garlic smells when you hold it).

4. Rub the freshly cut surface on the palm of one hand for 10 seconds (use the timer).

5. Rub the second piece of garlic on the palm of your other hand for 10 seconds (this way each hand gets rubbed with a fresh piece of garlic of the same size).

6. Rub one palm with the back of the stainless steel spoon and the other palm with the wooden spoon (the wooden spoon is our control experiment). Again for 10 seconds each. Make sure you remember which hand was rubbed with which spoon.

7. Find a willing volunteer, ask them to close their eyes (with their eyes closed they are less likely to notice any signals from you about which hand has had what treatment).

8. Hold a hand under their chin (that way each hand will be the same distance from the test subjects nose) and ask them to smell it. Then do the same with the other hand.

8. Ask them which hand smelt stronger of garlic.

9. Let me know the results using the survey below. We'll need plenty of tests if we are going to be sure of our results, otherwise it's just more anecdotes.

I'll  get back to you with a conclusion when enough results are in.

Create your free online surveys with SurveyMonkey , the world's leading questionnaire tool.

Number 22: Burning steel

What do you need to make stuff burn? Just three things, oxygen, a energy source to get it all started and some fuel. These three things are there every time you light a candle or start the engine of a car. The candle wax (or petrol) is the fuel, the match (or a spark) gets is all started and the whole thing is kept going with the oxygen in the air.


So what else can we get to burn? How about steel?

Steel is mostly iron mixed with some carbon and sometimes, other metals (depending on what the steel will be used for) and its not something you'd normally think burns.

You'll need

• Steelwool
• 9 Volt Battery
• Some old tiles or something similar that you don't mind getting scorched. 

Safety

This reaction generates a lot of heat (chemists call it an exothermic reaction) and can throw out sparks so make sure there is nothing near by that might catch fire. Have a bucket of water or fire extinguisher handy.  You can also end up with some small particles of steel wool being chucked up and you don't want to get them in your eyes, so wear safety goggles. Make sure there is a responsible adult supervising. Finally, because you get some smoke and sparks produced you should do this outside, you don't want to set fire to the kitchen.

What to do:

1. Fluff up the steel wool a bit. This is to make sure there is plenty of air in amongst it all.
2. Put the wool on the tiles (or whatever it it you are using)

3. Touch the terminals of the battery to the wool.

Almost instantly you'll see part of the wool glowing red hot, very quickly this spreads through the whole clump of wool, consuming it all. Like this:

What's going on:

When you burn things with carbon in them (these are known as organic compounds), like candle wax or fuel in the car, you are reacting the carbon with oxygen to make carbon dioxide gas (which has the chemical formula CO₂ meaning 1 carbon and 2 oxygens). But in this case there isn't any carbon to burn nor are we lighting anything with a flame. Instead the electricity from the battery runs through the steel wool and heats it up. This happens because the electrons and ions that form the electricity collide with other particles that make up the steel wool making them move around, and heat is just the result of particles (like atoms) moving.

The heat speeds up the reaction between the iron in the wool and the oxygen in the air. This would happen anyway, without your help, just much slower (that's why things rust). And this reaction produces heat (its exothermic) which kept the reaction going until you run our of fuel (i.e. the steel wool).

When you burn candles or wood you don't end up with much left over. That's because carbon dioxide is a gas, so it floats away. But when you burn steel wool you end up with iron oxide which is a solid, hence the black stuff that's left over. One more thing,  the chemical formula the iron oxide is Fe₂O₃ ie. 2 iron atoms (which have the chemical symbol Fe) react with 3 oxygens.