Liquid laughing gas supports combustion----make money online

in a previous episode I described how I

repaired this negative 100 degrees C

freezer and one of the things we can do

with those low temperatures is liquefy

nitrous oxide so I've got a bunch of

these little nitrous oxide cartridges

that are sold for whipped cream making

whipped cream at home and down in the

cold chamber there I've got a couple of

these cartridges so I'm going to do is

take one out and going to use the top of

the whipped cream cartridge opener just

to sort of pierce the top of the of the

little container there so normally if

this thing we're hot there would be tons

of gas coming out now it would have you

know let all the nitrous out but instead

you can kind of see a little bit of a

vapor trail coming out if I put it over

a test tube now we have a test tube of

liquid nitrous oxide so I'm going to put

this back down in the cold chamber to

keep the boiling down okay so there's

our tube of boiling nitrous oxide and to

see if it supports combustion or not I'm

going to put a burning piece of wood in

there and sure enough it does help

combustion let's do another one

the heat from the flame causes the

nitrous oxide to decompose into nitrogen

and oxygen and that additional oxygen

causes the flame to burn even hotter so

there's a bit of a positive feedback

loop okay see you next time bye

English (auto-generated)

How to chemically strengthen glass (eg Gorilla Glass)

today on Applied Science I want to talk

about glass why it breaks and how we can

strengthen it with a chemical process so

to get started let me show you this rig

that I built to test the strength of

these glass samples here we have a rigid

aluminum frame with two fixed aluminum

bars on the bottom and a pneumatic

cylinder on the top and the cylinder is

connected to this bar here so when I add

pressure to the cylinder it pushes down

on this middle bar and puts the piece of

glass which is a microscope slide in

bending and eventually when there's

enough force being generated by the

cylinder it snaps the slide I can

control the pressure very carefully by

dialing up the regulator here and the

gauge here and here will show the

pressure in the system all right so

let's give it a go

okay so that held about 24 psi before

breaking so I'll unload the pressure

here clean out the glass and I'll wipe

off the surface is there to make sure

that there's as little glass grit as

possible and now I'll try one of the

microscope slides that I treated with

the chemical process which I'll talk

about in a minute okay so that one broke

at about 60 to 70 psi so the process

really increases the strength quite a

bit let's talk about what's actually

going on here when we bend one of the

microscope slides in this test unit

what's actually happening is the top of

the slide is in compression you can see

the lines move closer together here and

the bottom of the slide is in tension

now glass like most brittle materials

can handle the compression just fine

it's actually the tension that's a big

problem and the reason is that all

pieces of glass in the world have

microscopic defects in them tiny little

cracks and when we bend the piece like

this those little cracks propagate

because they're being pulled apart by

these tension forces let me show you

with a piece of packing tape if I pull

on the tape like this you know I can

feel it stretching a bit but it's

certainly not breaking it's it's quite

strong however if I introduce a defect

just by slicing it a little bit with a

pair of scissors so that there's a cut

in it now you can see the defect and I

just pull on it there's no strength at

all and you could say yeah but the

material strength the plastic of the

tape is still as strong as it always was

I just added that defect but remember in

materials like glass there are a huge

number of defects in all pieces of glass

that you'll encounter in the world

they're distributed throughout the

material so it's actually the size and

the number of the defects that determine

how strong a piece of glass is

if we could somehow make a piece of

glass that truly had no defects

whatsoever it would be about a hundred

times stronger or more than most glass

that we encounter in the world so if we

want to make a piece of glass stronger

what can we do as it turns out with

current technology for a given size of

glass we actually can't reduce the

number of defects we can treat them

almost as a material property the

defects in the glass are one and the

same so what else can we do

well we identify that compression is

easy for glass to handle the tension is

a problem because it pulls open those

those defects and causes a failure

so if we could somehow eliminate the

tension force then we could effectively

make the material stronger and there's a

clever way to do this with a chemical

process most common pieces of glass in

the world have had sodium added to it to

lower its melting temperature so pure

silicon dioxide is great but it melts at

such a high temperature it's difficult

to work with so we add sodium oxide in

addition to lots of other things to

lower the melting temperature so here's

a diagram of what that might look like

this is a slab of glass here and the

small circles inside are sodium atoms

and this chemical trick involves

submerging the piece of glass in a

potassium salt so these larger circles

are potassium atoms and through the

natural process of diffusion some of the

potassium atoms will take the place of

the sodium atoms in the piece of glass

so what's happening here is these larger

potassium atoms are being shoved into

the spaces where there used to be just a

very small sodium atom and the effect is

that were basically shoved the glass put

the glass in compression by jamming

these larger atoms inside of it now this

process happens at a temperature lower

than the glass softening point so the

glass is still hard when this is

happening and as we're shoving in these

larger atoms the glass is becoming

increasingly put into compression

however the center of the glass is not

affected by this process as quickly

because this is like a diffusion process

and so it takes a while for these

potassium

items to work their way into the glass

so if we cancel the process after a

certain amount of time the center of the

glass will not have this effect at all

and the edges will will be in

compression so after the treatment what

we have is something like this where the

edges of the piece of glass are in

compression and the center of the glass

is actually in tension because of all

those extra atoms that we jammed in

around the periphery and this is true

around the edges do but I'm just showing

it in one direction so later when we

load the piece in bending the top gets

to be even higher in compression the

center is still in tension but the

bottom layer which would normally be in

tension in a bending situation like this

is now either neutral or at least it's

offset quite a bit because of that

residual compression is sort of

cancelling out the tension that would be

created by this loading scenario so

we've effectively strengthened the piece

of glass by pre loading it in

compression we were able to get rid of

some of that tension loading another way

to think about this is that the

compression that we've added to this

edge of the glass helps close the cracks

so when we put this in bending this

crack here the defect doesn't shoot up

through the glass and cause breakage

because we're in compression here and

it's actually sealing the crack shut the

process is pretty straightforward I set

up a stainless steel container in a

small kiln and added to it some

potassium nitrate that I bought on ebay

Ilene's the glass microscope slides

against the stainless container and then

turns the kiln on and set it to about

425 degrees centigrade after the kiln

came up to temperature I opened it up

and noticed that the potassium nitrate

had quite a few impurities floating on

the surface so I fished those off and

then added the slides to the now molten

potassium nitrate since the process was

going pretty well I also up to the

temperature to 450 degrees after three

hours at that temperature I fished the

slides out and let them cool as slowly

as possible that I didn't do anything

special like put them into a temperature

controlled chamber

I just put them out in air after they

cooled down naturally I washed the

slides off in tap water and then loaded

them into the test rig and tested their

strength so did we just make gorilla

glass no not quite actually gorilla

glass is a proprietary blend of

ingredients it's actually the starting

point of the glass the chemical

strengthening that I've described in

this video has long been out of patent

protection and lots of people do it the

special thing about Gorilla Glass is

that it has a very unique set of

ingredients that make it especially

amenable to this chemical strengthening

process okay see you next time byeearn money online without investment for students, earn money by clicking ads, earn money online without investment, online earn money website, online jobs to earn money, best online income site, top 10 online money earning sites, easy income online, easy online earning, earn money online from home, make money online legit, earn money online free fast and easy, online earning websites list, genuine online money earning sites, online work to earn money, online surveys to earn money, earn money through internet, best online income, earn money online data entry, easy ways to make money online, best online earning websites, top websites to earn money, online typing jobs for students to earn money, earn skrill money online, earn skrill money,