Saturday 19 June 2010

Things you learn from the television

In yesterday's repeat of Supersize vs Superskinny, some hypnotist-dietician lady said that potato crisps were really unhealthy because they were soaked in fat, and to prove it she would set fire to one.

The crisps she was holding burned far more brightly and for far longer than paper, and I said that I thought that she had faked it (by dipping the crisps in meths or something). My wife reckoned it was possible, so I I thought I'd have a try.

To my amazement it works.

The posh Tyrrell's crisp (sweet chilli and red pepper) burned half way down and then went out, so I put it outside on the step. After a couple of minutes, I picked it up again by the charred half and set fire to the unburned half, and that was even more impressive, there were even tiny little jets of blue flame round the edge.

The normal Walker's crisp (ready salted) was much easier to light than the Tyrrell's one and being thinner burned out rather faster.

Safety tip: burning chips drip very hot fat, so don't let it drip onto your skin. It's probably not very good for most floor-coverings either.

7 comments:

Anonymous said...

During my drunken youth, much fun was had burning poppadoms -- takeouts only, I must hasten to add, not in restaurants! Try it; they'll put your crisps to shame...

Macheath said...

I'm impressed by your efforts on our behalf in the interests of science - I'm not sure I'd be prepared to sacrifice a premium crisp for an experiment, let alone relight the unburned part instead of eating it.

Mark Wadsworth said...

Morlock, ta for the tip, I must try that.

McH, you're allowed to eat the rest of the packet, of course. Even though emptying one or two packets into a bowl and setting fire to the whole lot must be worth considering.

Mrs Rigby said...

You did science! That's how they work out the calorific value of foods.
1 cal = heat to raise temp of 1 kg of water by 1 degree

Here you go! http://www.npr.org/templates/story/story.php?storyId=6493713 Have fun.

Try burning a peanut, or even a raisin!

Mark Wadsworth said...

Mrs R, can you really burn raisins? Only one way to find out...

dearieme said...

That's one reason why the calorific values reported for foods can be misleading. If you burn them in a calorimeter, you trap all the energy available by oxidation. But there's no guarantee that your stomach does the same - some of the food is exhausted unoxidised.

Mark Wadsworth said...

Update, raisins don't burn, or at least not in the sense of 'they will give off a flame'.

D, exactly, but it's a fair rough and ready guide for the small minority that take an interest in such matters.