[Nfb-science] science experiments

[kenny agni]

cool!


On Tue, Jan 29, 2013 at 2:53 PM, David Evans wrote:

> Dear All,
>
> As a Materials Engineer, I have used a demonstration of how shaping or 
> stressing a material can change its properties.
> I take a simple water glass and place a dollar bill, flat across the 
> mouth of the glass.
> To this I place a coin such as a quarter on the top of the dollar and 
> watch as the dollar collapses into the glass, showing that the 
> material, in its present form and shape is not strong enough to 
> support the weight of the single coin.
> I then take the dollar bill and fold it back and forth, lengthwise in 
> a corrugated fashion.
> I then lay the same dollar across the mouth of the water glass and 
> begin stacking coins of the same weight and size on top of the dollar 
> bill until it fails.
> I then ask the question, " What changed in the material and what did 
> it do to effect the material and the outcome of the experiment?
>
> The stressing of the material gave it greater directional strength and 
> the shaping of the material also made it act like a thicker piece of 
> the same material with a thicker apparent cross sectional area..
>
> Other demonstrations can be done that show how stressing or shaping 
> materials in to certain shapes are used to give greater strengths or 
> other properties to materials, which is key in the field of 
> fabrication and construction.
>
> David Evans, NFBF and GD Jack.
> Retired Nuclear/Aerospace Materials Engineer
> Builder of the Lunar Rovers and the F-117 Stealth Fighter.
>
> ----- Original Message ----- From: "Larry D. Keeler" 
> <lkeeler at comcast.net>
> To: "NFB Science and Engineering Division List" 
> <nfb-science at nfbnet.org>
> Sent: Monday, January 28, 2013 2:27 PM
> Subject: Re: [Nfb-science] science experiments
>
>
>> If the experiment is osmosis you can do many things. My favorite is 
>> first to take an egg and soak it in vinegar for a couple of weeks. 
>> Weigh it and then put it in water.  This gives kids a few things to 
>> learn.  First, they casn observe the chemical reaction of the calcium 
>> with the vinegar.  Or rather acetic acid.  Next, you really have in 
>> effect a large cell complete with organelles and membrane.  Lastly, 
>> you can then prove that water crosses cell membranes by putting the 
>> egg in the water.  The egg not only becomes firm but its weight 
>> increases.  The last thing you could do is iether put the egg in some 
>> anhydrous matterial and draw the water back out, thus shrinking the 
>> egg.  Maybe alcohol might do that.  Which could also show what 
>> happens to cells when one drinks alcohol.  The sponge idea is faster 
>> but the egg thing is a whole lot more fun!  You can also play ball 
>> with the eggs if they stay in the vinegar too long!
>> ----- Original Message ----- From: "Pickrell, Rebecca M (TASC)" 
>> <REBECCA.PICKRELL at tasc.com>
>> To: "'NFB Science and Engineering Division List'" 
>> <nfb-science at nfbnet.org>
>> Sent: Monday, January 28, 2013 2:08 PM
>> Subject: Re: [Nfb-science] science experiments
>>
>>
>>> Those toys got banned? Really? My daughter loves them!
>>> Please tell me we're talking about something different. I've been 
>>> meaning to put one in the bathtub to see how big it will get.
>>>
>>> -----Original Message-----
>>> From: Nfb-science [mailto:nfb-science-bounces at nfbnet.org] On Behalf 
>>> Of Blaine Clark
>>> Sent: Saturday, January 26, 2013 3:14 PM
>>> Subject: Re: [Nfb-science] science experiments
>>>
>>> If you can get some of those dried sponge toys that have recently 
>>> been
>>> banned in the US because they pose a health hazard to small children 
>>> who
>>> can swallow them, you can let your students feel them before they go
>>> into the water and perhaps two or more can keep their hands on them 
>>> in
>>> water as they expand. You could even just partially immerse them so 
>>> they
>>> could feel the portions under water versus the portions above water 
>>> and
>>> tell how the water/air division area softens and partially expands 
>>> as
>>> water starts to creep up. You should be able to do this with regular
>>> hard dried sponges too.
>>>
>>>
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>>
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>
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