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Author Topic: How could I build a heat-reactive spoon?  (Read 5780 times)

Paul Farquharson

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How could I build a heat-reactive spoon?
« on: 05/12/2010 17:36:18 »
Paul Farquharson  asked the Naked Scientists:
   
Dear Chris,

 My name is Paul Farquharson and i would love some assistance on a quick query i have.  I am currently studying Art and Design at Dundee college and we have been giving a brief to design a spoon for a company or specific person.  My idea was to do a talking spoon for a gifts company, the spoon will be in the shape of a monkey at the handle and its tale will make up part of the head, as the tail is put in the hot water a heat sensor in built into it will set off the speaker in the back of the body which will make a monkey noise "ooh aah" as if the liquid is too hot for the monkey. Although i studied physics at school it was more than 15 years ago and i am very rusty, i would be very grateful if you could give me a brief run down on the technology i would have to put in the spoon for me to include in my project.

Many thanks
Paul Farquharson

What do you think?
« Last Edit: 05/12/2010 17:36:18 by _system »


 

Offline peppercorn

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How could I build a heat-reactive spoon?
« Reply #1 on: 05/12/2010 21:29:01 »
Simple circuit using with one of these:

http://en.wikipedia.org/wiki/Thermistor
 

Offline CliffordK

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How could I build a heat-reactive spoon?
« Reply #2 on: 05/12/2010 22:14:27 »
A spoon that makes noise?

One of the reasons that I use "NoScript" on my computer is that I hate websites that blast me with unwanted sounds.

If you do add electronics to your spoon, it will have to be washable.  So, either it will have to come apart, or it will have to be dishwasher safe.  And, it should still be pretty water resistant.

You might also just consider those color changing plastics that some people are putting on cups...  And just have some colorful display.  It probably would be limited to locally around where the heat contact is, unless you added some type of copper heat transfer...  and then you would have to make sure it didn't get too hot.

 

Offline peppercorn

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How could I build a heat-reactive spoon?
« Reply #3 on: 05/12/2010 22:22:48 »
Cliff: "So, either it will have to come apart" - The option I'd go for.
Does this college project involve actually making the device or simply describing the design and manufacturing steps on paper?
The same all-on-chip tech used in audible greetings cards could be used or the 'speech'.
 

Offline Geezer

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How could I build a heat-reactive spoon?
« Reply #4 on: 05/12/2010 23:43:30 »
You could make it out of memory metal so that it recoils as it approaches a hot liquid, or make it out of chocolate and it will simply disintegrate.
 

Offline Chemistry4me

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How could I build a heat-reactive spoon?
« Reply #5 on: 05/12/2010 23:49:45 »
Speaking of disintegrating chocolate spoons...

Quote
a classic prank invented in Victorian times was to cast spoons from an alloy containing 8 parts Bismuth, 5 parts lead and 3 parts tin. Its melting point is low enough for the spoon to vanish into a cup of hot tea...

http://www.rsc.org/chemistryworld/podcast/Interactive_Periodic_Table_Transcripts/Bismuth.asp
 

Offline CliffordK

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How could I build a heat-reactive spoon?
« Reply #6 on: 06/12/2010 07:17:20 »
If you want a melting spoon...  pick a lead-free, cadmium-free, mercury-free alloy.

http://www.rotometals.com/Low-Melting-Alloys-s/21.htm

But...  when I was younger, my grandparents had a spoon they had just torched the end off of.  They'd stick it in the cup, then pull it out and proclaim "ooo..  Strong coffee".

The thermistor above would be good...  and pretty simple.  I'm not sure of the circuitry in it, but you cold probably make one.  The other thing you could do is put in an IR sensor. 

I.E.  You have a handle that slips over the spoon.  Remote IR sensor, and you have the exact temperature to process with your electronics.

An electronic Christmas Card might give you some ideas of how to wire the circuitry in the spoon.
 

Offline RD

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How could I build a heat-reactive spoon?
« Reply #7 on: 06/12/2010 08:03:54 »
A plastic which changed colour would be simpler and cheaper temperature gauge than one which used electronics or memory metal ...




Quote
This fun baby feeding bottle reacts to heat and is specially designed to change colour from purple to pink at approximately 35degrees celcius.

The bottle is made from BPA-free polypropylene food grade material and non toxic colour changing pigment. 

Extreme temperature and long term direct exposure to UV light will reduce the lifespan of the bottles colour-changing properties.

http://www.babygrowsafe.com.au/discontinued/milk-tickles-colour-changing-bottle/prod_63.html


Say the tail of the plastic-monkey-spoon turns red when the temperature is above XoC


[just noticed I am repeating CliffordK's point]
« Last Edit: 06/12/2010 08:53:26 by RD »
 

Offline CliffordK

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How could I build a heat-reactive spoon?
« Reply #8 on: 06/12/2010 10:52:36 »
Those heat sensitive coatings are used in a variety of drinking glass/mug applications.

This one is bouncing around the internet now...  "Global Warming Mug"

http://www.amazon.com/Unemployed-Philosphers-Guild-004028-Warming/dp/B000OYSPYK/ref=sr_1_1


The problem is that the hot drink may not activate the spoon handle without some clever tricks.
 

Offline Mazurka

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How could I build a heat-reactive spoon?
« Reply #9 on: 06/12/2010 16:14:01 »
How about using a bimetallic strip in some way?  A coiled moneky tail that pushes the monkey up out of the cup in case of hot water?   
 

Offline imatfaal

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How could I build a heat-reactive spoon?
« Reply #10 on: 06/12/2010 17:05:42 »
You could have a coiled tail that clings to side of mug - till it releases (as it cools), and when you can remove the spoon you can drink the tea; cos all well brought up peeps know that you must never drink from a cup with a spoon in
 

SteveFish

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How could I build a heat-reactive spoon?
« Reply #11 on: 06/12/2010 19:16:10 »
I got some of the 700c Woods metal (bismuth, cadmium etc.), but it wouldn't work for my specific application. I sure had some fun with this stuff though. For example, pouring what appeared to be melted lead into my cupped hand in front of somebody. Nasty heavy metals though.
 

Offline pcentauri

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How could I build a heat-reactive spoon?
« Reply #12 on: 02/01/2011 21:25:01 »
newbielink:http://www.disappearingspoons.com [nonactive] sells molds & gallium metal to make gallium spoons that melt at 86F
 

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How could I build a heat-reactive spoon?
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