
An Ikea Bowl Has Been Setting Things on Fire - tomcam
http://www.atlasobscura.com/articles/ikea-bowl-blanda-blank-fire
======
Freak_NL
The same phenomenon occurs with glass spheres. If you think about it it is
obvious enough (most people are familiar with how a magnifying glass
concentrates the ray of the sun in a single spot), but it is something people
tend to overlook when employing glass spheres as elements of your interior
design — e.g., glass door knobs, large marbles, and decorative knick-knacks
(which people have a tendency to place on their windowsills).

Every once in a while a house fire is started because the sun sat at just the
right angle at a certain time of the year, placing the focal point on the
curtains. But because the risk is so low (it doesn't happen that frequently)
many people are completely unaware of the phenomenon.

~~~
buserror
Actually one of the official 'old school' tool to measure sun exposure thru
the day in meteo stations is a glass sphere with a calibrated piece of paper
underneath. Needs to be changed everyday, but the burn mark is quite neatly
drawn on the chart.

EDIT: Found it again
[https://en.wikipedia.org/wiki/Campbell%E2%80%93Stokes_record...](https://en.wikipedia.org/wiki/Campbell%E2%80%93Stokes_recorder)

~~~
shagie
One of the photographers that I'm intrigued by is Michael Wesely (
[https://en.wikipedia.org/wiki/Michael_Wesely](https://en.wikipedia.org/wiki/Michael_Wesely)
) who takes ultra long exposures (a two week long exposure is "short" \- his
flower photographs are in that range). The museum of modern art was about two
years. [http://www.amusingplanet.com/2010/08/unusually-long-
exposure...](http://www.amusingplanet.com/2010/08/unusually-long-exposure-
photographs-by.html)

You can see the tracks of the days and the cloud cover in those photographs.
Note that the multiple year ones have multiple days going over a single track.

Aside from the extreme reciprocity failure in the film, its "only" about three
stops from a one day exposure to a one week exposure... and another two stops
to a month, and then another three and a half stops to a year.

~~~
buserror
Thanks for the reminder on the reciprocity rules! I used to take super-long
exposure with my 4x5/10x8 view cameras as well... basically after a few
minutes, it doesn't /really/ matter anymore so stop counting in
minutes/seconds, more in teacups+newspaper pages :-) I always loved the tonal
range you get on way, WAY overexposed film.

~~~
shagie
Digging up an old page (I am not sure if the film still has that
characteristic curve), Provia 100F had some very nice _lack_ of reciprocity
failure.
[http://home.earthlink.net/~kitathome/LunarLight/moonlight_ga...](http://home.earthlink.net/~kitathome/LunarLight/moonlight_gallery/technique/reciprocity.htm)
(from
[http://home.earthlink.net/~kitathome/LunarLight/moonlight_ga...](http://home.earthlink.net/~kitathome/LunarLight/moonlight_gallery/)
\- its an old frames page).

The correction for a 1200 second (20m) exposure on Kodak black and white film
was at 12x (for 14400s, 4h). However, the extrapolation for the curve for
Provia 100F put the reciprocity failure for 1200s at 2.35 for a 3000 second
exposure.

Looking at the methods and results is interesting, though I've gone nearly
full digital now.

------
okket
Works also with skyscrapers:

[http://www.bbc.com/news/uk-england-
london-23930675](http://www.bbc.com/news/uk-england-london-23930675)

~~~
nailer
Same architect did the same thing with their previous building, then didn't
learn their lesson.

~~~
Leynos
I still wonder if it was more a case of wanting to see how many times they
could get away with it.

~~~
efaref
I think he did learn the lesson, but then his fix for it was removed in the
cost-cutting phase.

[http://www.telegraph.co.uk/news/newstopics/howaboutthat/1029...](http://www.telegraph.co.uk/news/newstopics/howaboutthat/10290615/Cost-
cutting-could-have-caused-Walkie-Talkie-skyscraper-ray-damage.html)

------
NicoJuicy
"Archimedes heat bowl" would be a better name,

Wikipedia: "The device, sometimes called the "Archimedes heat ray", was used
to focus sunlight onto approaching ships, causing them to catch fire. "

[https://en.wikipedia.org/wiki/Archimedes](https://en.wikipedia.org/wiki/Archimedes)

~~~
camiller
I believe that mythbusters had an episode disproving the Archimedes heat ray

~~~
dacohenii
They tried and failed three times (episodes 16, 46, and 157).

Here's an interesting write-up about the team of MIT students that worked with
them on the second try:
[http://web.mit.edu/2.009/www/experiments/deathray/10_Mythbus...](http://web.mit.edu/2.009/www/experiments/deathray/10_Mythbusters.html)

------
thesz
Can't help myself:
[https://www.youtube.com/watch?v=uJuuFLo1a84&t=252s](https://www.youtube.com/watch?v=uJuuFLo1a84&t=252s)

Getting fire with the spoon (!) in Siberia's (!!) Winter (!!!).

The sun light is not very bright at that time, just for a note. Sun is about
couple tens of degrees above horizon and (infrared) light mostly caught by the
atmosphere.

~~~
tekromancr
"Sure, it's cold—but to a fire, everything is cold" [https://what-
if.xkcd.com/155/](https://what-if.xkcd.com/155/)

~~~
thesz
My note was mainly about sun ascension, not temperature.

------
aj7
The focal length of a spherical mirror is R/2\. The focus is not perfectly
sharp, but gets sharper if the mirror shape approaches a parabola. Finally,
for a symmetrical bowl, the effect is greatest at high noon, since off-axis
rays are not focused to as intense a spot as rays parallel to the bowl axis.

------
nthcolumn
Feature. Not a bug.

~~~
Aaargh20318
Basically, it's a marketing/naming problem. They should sell it as an eco-
friendly fire starter.

~~~
agumonkey
Free Energy Maxx Heater

------
jlebrech
they can change the description to self lighting bbq and give it legs.

It's also on my list of things to bring on a desert island.

~~~
masklinn
You'd probably be better off with a magnifying or fresnel lens (or set of
lenses), they're available as portable/survival tools (sometimes called "fire
lenses" or "burning glass").

Fresnel are convenient as they're available in flexible flat rectangular
plastic (e.g. credit-card sized). You lose in image quality so it's not great
if you're trying to look at mosses or small critters, but to set stuff on fire
it's really great as they're light, easy to pack and can be much larger than
glass magnifying lenses (of equivalent or lower convenience).

~~~
cr0sh
I carry three or four different means to set a fire in the backpack I carry
when I go hiking; a credit-card sized fresnel lens is one of them.

I also like to scavenge the huge fresnel lens from larger (40+ inch) rear-
projection TVs - these are often thrown out by people during our "bulk-trash
pickup" days. It only takes a few minutes of work to remove the front screen
of the TV (they are designed to be removed). A few more minutes will net you a
huge silver first-surface mirror, too.

The fresnel lens from one of these TVs - mounted in a proper frame - can
easily melt steel and rock. You have to be very careful when using it (wear
proper clothing, plus welding goggles and gloves), and store it properly out
of the sun afterward (because it can easily set things randomly on fire you
don't want set on fire).

------
symmetricsaurus
It concentrates the sun from what I could understand from the article. Should
work the same for any spherical bowl (parabolic would work even better) that
is shiny enough.

~~~
gebruikersnaam
It's a known way of cooking[0], saw them in Tibet years ago.

[0]
[https://en.wikipedia.org/wiki/Solar_cooker](https://en.wikipedia.org/wiki/Solar_cooker)

------
dsfyu404ed
I hope they don't change the design. This would be great for
camping/hiking/backpacking. Having a bowl that's also capable of starting a
fire is a nice extra safety measure and it takes up almost no space because
you pack stuff into it.

~~~
joeframbach
I can't quite remember the exact make or model, but years ago there was a
lightweight folding camp chair which has a removable plastic support. Its
shape was perfect for a makeshift arm splint. Many people suggested that this
camp chair should be part of their go-to gear. The following year the chair
was redesigned without the removable support :(

------
mmjaa
I'm definitely going to buy one of these bowls just for this highly useful
feature...

~~~
sswaner
If you don't live close to an IKEA store:
[https://www.amazon.com/dp/B00T5YMQIG/ref=cm_sw_r_sms_awdb_IY...](https://www.amazon.com/dp/B00T5YMQIG/ref=cm_sw_r_sms_awdb_IYJuzbESBKGB1)

~~~
agumonkey
Thanks, not a trigger buy thing at that radius / price. Rare as second hand
things, so far people liked the product it seems. Or died since.

------
agumonkey
Smiling hard, I was looking for a solar concentrator online when I should have
gone to the nearest IKEA store.

ps: a video that go well with the PrimitiveTechnology channel

~~~
cr0sh
If you live in the US (or you know someone), and you have bulk-trash pickup
(or can scavenge otherwise) - look around for an old 40 or 50 inch rear-
projection television. All of them use a large fresnel lens for the screen
(they also have an interest lenticular lens as well - but that isn't as useful
due to it's short focal length). This lens, properly mounted, is capable of
melting glass, rock, steel, etc. IE - if you use one as a solar concentrator,
know what you are doing, as they can be very dangerous (not a toy). There are
plenty of instructables and such online detailing how to build and use one -
for instance:

[http://www.instructables.com/id/Giant-Fresnel-Lens-
Deathray-...](http://www.instructables.com/id/Giant-Fresnel-Lens-Deathray-An-
Experiment-in-Opti/)

~~~
agumonkey
Yeah I know, I've seen these dozens of time on youtube[1], but there's not a
lot of these TV around anymore; or I need to find a real landfill.

A large fresnel lens is my most wished prize right now, I consider looking
into manufacturing one.

[1] to recycle glass, metals etc, maybe produce some cute things or just to
ease trashing (bins won't contains large empty bottles, but nice pellets)

------
maxmcorp
I suddenly smelled smoke one morning and could not figure out where it came
frome. Turned out it was a paper napkin i had left in one of those bowls on my
kitchen table. And the sun came in through the window in just the right angle.
Took me a few minutes to figure out what the reason was.

------
shanev
A similar phenomenon causes birds to spontaneously combust when flying near
industrial solar power plants:
[https://www.youtube.com/watch?v=ICLXQN_lURk](https://www.youtube.com/watch?v=ICLXQN_lURk).

~~~
camiller
Hmmm.... spontaneous would be without an external source of ignition, which is
the solar concentrators of the power plant. Probably more accurate to strike
spontaneously and simply say "...causes birds to combust when flying near ..."

~~~
shanev
Right, but the source of ignition here is invisible to the human eye. So it's
bit of a grey area.

------
anc84
Original source: [https://www.thelocal.se/20170620/video-ikea-bowl-sets-
swedes...](https://www.thelocal.se/20170620/video-ikea-bowl-sets-swedes-
grapes-on-fire)

------
koolba
Is this a basic parabola effect by focusing the suns rays on a single point?

~~~
znpy
Yes, basically.

~~~
amelius
But actually how close is the bowl to a parabola?

~~~
swampers
Hopefully not too close, or else the parabola will be set on fire.

~~~
cwilkes
I LOLed

------
alfonsodev
could be this adapted receive better wifi signal ?

~~~
datenwolf
Of course. As a matter of fact I once bought that very exact bowl for making a
S band dish antenna.

There's a small caveat: The bottom of the bowl is flattened (so that it
doesn't roll around). That's not a big deal though if you use a dipole feed;
since the dipol radiates mostly normal to its axis (look up the pattern if
it's unclear what I mean) a dipole mounted at the center and perpendicular to
that flatted base will actually not "see" much of that flat base and work only
against the curved part.

Due to the rather small radius and being a spherical shape the
directivity/gain is not that great, compared to a parabolic dish antenna. But
it's cheap and works well enough if you have to cover only a couple of km.

However keep in mind that regulations likely limit maximum transmission power
to something like 20dB(m) EIRP, so depending on how much directivity gain you
get, you'll have to reduce the TX power by that amount to stay legal… or get a
license.

------
anotheryou
A friend of mine had some prism on the window sill and the curtains cought
fire. Luckily he was in the room and noticed.

------
lgleason
In other news, sales of the bowl spike :).

------
JaggerFoo
Viewing the video I see that the paper smolders, smokes and burns, but I see
no flames that consume the paper.

So it does not set things on fire.

Maybe change the title to "An IKEA Bowl Has Been Burning Things"

------
13of40
I have a stainless steel saucepan from IKEA that I've used for camping for
several years, and on a bright day, with some effort, I can start a fire with
the lid.

------
z5h
At my daughter's 2nd birthday, my mom had to put out a fire that spontaneously
occurred in a bowl of chips outside. Not sure if it was this bowl or a
doppelganger.

------
DoubleMalt
Reminds of this (sadly discontinued) project:
[http://www.photongrill.com/](http://www.photongrill.com/)

~~~
prawn
There's also this parabolic solar camp stove I spotted on the REI site a few
months ago. Seems like an absolute gimmick, but the few reviews are all very
positive:

[https://www.rei.com/product/100561/gosun-sport-solar-camp-
st...](https://www.rei.com/product/100561/gosun-sport-solar-camp-stove)

~~~
sswaner
The Boy Scout handbook (1980's version) had an aluminum foil solar oven design
for cooking a hot dog. It was a version of that psychology test of putting
marshmallows in front of kids. The patient scouts got a cooked hotdog in about
45 minutes - on a bright summer day. I ate a raw one after about 10.

~~~
logfromblammo
Unfortunately, my kids already know from watching _How It 's Made_ that most
wiener-type sausages sold in the US are fully cooked at the factory, and when
you "cook" them at home, you're just heating them up. One would just eat it
without bothering with the foil for even one minute, and the other doesn't eat
hot dogs at any temperature.

I remember, as part of a wilderness survival challenge, being told to eat some
breakfast, then they gave me one match, a juice can, a raw egg, and two
uncooked pork sausage links. The "correct" solution was to build a fire, drink
the juice, cut the top off the can, grease the inside of the can with cooking
sausage, and then fry your egg in the greased can. Alternate solutions turned
out to be a whole lot easier--left as an exercise for the reader because many
of them are disgusting.

Knowing how to do this was of great comfort to me, because sausages, eggs, and
juice cans actually grow on trees in the woods near me. Along with plastic
tarps and alkaline batteries. It felt like the sort of thing that might give
kids just enough confidence to wander off alone to die in the actual
wilderness, or to miraculously return in five years speaking fluent Wolf, with
plenty of helpful suggestions for the next edition of the manual--such as a
primer on the intricacies of wolf pack politics.

That manual probably should have just skipped the solar oven and gone straight
to starting a fire with the foil. (As though your average Boy Scout doesn't
already know too many ways to set something on fire. Have you ever seen
someone start a bonfire by shooting an arrow into it? That guy was probably a
Boy Scout, and the secret he wouldn't tell you is that the tinder had KMnO4 in
it, and the arrow popped a hidden balloon with some glycerol in it. It wasn't
actually a ghost.)

~~~
cr0sh
> that the tinder had KMnO4 in it, and the arrow popped a hidden balloon with
> some glycerol

For those that don't know, KMnO4 is also known as potassium permanganate:

[https://en.wikipedia.org/wiki/Potassium_permanganate](https://en.wikipedia.org/wiki/Potassium_permanganate)

As noted in that wikipedia article, when combined with glycerol or other
glycerin containing products (like automotive antifreeze) it can also be used
as a fire starter. It can be easily found online or at home improvement
stores, as it is sold for water softening and filtration purposes.

Grant Thompson ("King of Random") documents how to make a survival fire
starter kit using this knowledge:

[https://www.youtube.com/watch?v=ja_6Yin9JuM](https://www.youtube.com/watch?v=ja_6Yin9JuM)

In short, keeping a bit of potassium permanganate in your car with you, should
you get lost and don't have another source of fire making with you, might be a
wise thing (then again, if you know anything about automobiles, there are tons
of ways to use parts in them for starting a fire).

~~~
HeyLaughingBoy
You just had to post that, didn't you!!!

Got a bottle of KMnO4 next to my iron filter and at least one jug of glycol
antifreeze in the garage.

Guess what I'm doing when I get home :-)

------
r3pl4y
That's going to be the most sold bowl Ikea ever had, due to all the people who
want to try this at home

------
pulse7
This is great if you need fire and you don't have matches...

~~~
ythn
I think it would actually be quite difficult to start a fire with this.
Speaking as a former boy scout who had to build a fire with a magnifying glass
for wilderness survival merit badge - it's really easy get smoke, it's quite
difficult to get a flame.

The article claims that he "set a piece of newspaper on fire" using the bowl,
but after watching the video I just saw some smoldering paper - no flames. I'm
betting the grape stem just smoldered a bit as well.

You have to have very good airflow with dry, fine tinder in order to start a
fire with a magnifying glass or parabolic mirror... unless of course you build
a lens or mirror of monstrous proportions.

~~~
dekhn
I can set a piece of cardboard on fire with visible flames in a few seconds. I
carry a small fresnel lens, [https://www.amazon.com/3-Pack-Credit-Card-Pocket-
Fresnel/dp/...](https://www.amazon.com/3-Pack-Credit-Card-Pocket-
Fresnel/dp/B00NWMUK0I)

~~~
ythn
I still maintain that it is much more difficult to start a fire with a lens or
mirror than people seem to think. Post a video of using your fresnel lens on
different material types (paper, cardboard, wood, pine needles) and see how
quickly you can get a visible flame. I'm betting you won't be able to easily
get a visible flame on most materials you try.

~~~
cr0sh
> I still maintain that it is much more difficult to start a fire with a lens
> or mirror than people seem to think.

I'd have to agree with you. When I go hiking, I carry around 3 or 4 different
kinds of "fire making" things, just in case I need them for any reason. I also
practice with them on occasion to know what to do when I really need them.

It isn't easy to start a fire from scratch. It takes a bit of work, a bit of
knowledge, and a ton of patience and perseverance. If you don't have any of
that, you'll have a hard road ahead of you.

Even using good tinder plus magnesium bar shavings and a flint striker isn't
as easy as you'd hope. In fact, it can be very frustrating. But once you get
it going, it's very satisfying.

This is why I also carry a Bic lighter, strike-anywhere matches (in a
waterproof container), esbit tablets, and a fresnel lens - all as backup fire
sources.

------
jensv
Great for camping trips.

------
StreamBright
Excellent doomsday fireplace with self ignition capabilities.

------
nailer
I own one of these! Anyone on HN have ideas for pyro fun?

~~~
VA3FXP
Not pyro-based fun, BUT a fun project nonetheless. Take a laser-pointer(s) and
at multiple intervals map the trail of the reflection. Find out where the
focal point is, and post for fun.

For bonus geekiness use some dry-ice to better illuminate the path.

------
orzen
Starting with clickbait...? Shame, shame

~~~
yitchelle
To be serious, title describes article accurately. Click bait style of title
is a side effect.

------
dekhn
ordered, thanks. I needed a cheap parabolic to start fires.

------
such_a_casual
fucking parabolas man

------
SurrealSoul
Curious how clickbaiting works now. Taking the articles title "This Ikea Bowl
has been setting things on fire", the "This" is an interesting word choice
that is a great reminder of the "You won't believe THIS simple trick to..."
that started the whole craze. I'd be curious to see some A/B testing on semi-
baiting titles vs something more descriptive like the original source 'Ikea
investigates after 'bowl sets Swede's grapes on fire'

~~~
elliottcarlson
Where is the line between clickbait and attention grabbing headline. In the
case of "You won't believe THIS simple trick to..." I'd definitely call it
clickbait - but in this instance, the title reflects exactly what the article
is about, and while the modified title on HN does a far better representation
of the contents, I personally don't see the harm in how Atlas Obscura worded
the title.

Or maybe I am just really susceptible to clickbait titles...

~~~
burkaman
This is a very minor example, but compare the title to just "Ikea Bowl Has
Been Setting Things on Fire". The word "this" naturally prompts the response
"which one?", just like something saying "look at this" in real life. Again
it's very minor, but the extra word adds nothing except a slight suggestion
that this particular example is especially interesting and you should click to
see it.

Compare "Florida Man Escapes Prison" to "This Florida Man Escaped Prison".
You'd scroll past the first, but you might not scroll past the second, because
it seems like there must be something particularly interesting about this
florida man, so you might as well take a second to click and see the picture.

~~~
ptaipale
Yes, except that "This" in a title is a definite turn-off for me, and a sure
way to make me avoid clicking. So sick of baiting.

~~~
netsharc
Reddit has a bot that summarizes articles. A browser extension that replaces
each Buzz! Feed! Headline! with such a summary would be an interesting
programming exercise.

Or maybe not Buzzfeed, since even the summary will cause brain cancer.

