[Nfb-science] science experiments

[David Evans]

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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