CaptainPanic

There are good alternatives for many plastic products. But we should first of all realize that a lot of plastic is in fact no "product", but a packaging material. For packaging, no high quality materials are needed. Paper or recyclable materials can be used. We can reduce the plastic consumption easily, especially packaging materials. If you look at an average pack of cookies, then often each cookie is packed separately. Then they're all neatly put in some kind of shape, for the purpose of keeping them in 1 piece while being moved (rough handling is now possible), and presentation. They are then wrapped into a colorful packing plastic, put together in a box, which is cealed in again more plastic. And it's not uncommon that even more layers are added to the packaging. And often these cookies have traveled further than I have in my lifetime. Also, I cannot remember when was the last time I have had anything electric repaired. We don't even seem to consider the option: throw it away and buy something new. In fact, electric appliances are constructed with special screws with the sole purpose that you cannot open it yourself. You're not supposed to be able to re-connect some loose wiring. (Imagine the claims if you'd electrocute yourself).... that all leads to more and more waste, and in the same time it serves the economy well. There is also still a habit of getting a plastic bag with everything you buy. It's a worldwide habit not to take your own (empty) bag with you when you go shopping. My point (in short): let's focus on reducing plastic consumption as well as on replacing it by sustainable materials.

If you plan on heating any metal oxides with carbon present, clear out the oxygen with extra CO2 or N2 please... heating flammable liquids (ethanol) with a torch is just a very bad idea... especially if you put them in a bottle first. You will not just get fire, you'll get an explosion and then a fire. Also, you are planning to: make a gas in an air-tight place (you suggested a bottle). If it works, you will build up pressure (that means it can explode even without ethanol)... meaning you need to make sure (very sure) that this air-tight place is strong enough to contain that pressure, or that you have a release valve for the CO2 buildup. Are you sure you need this Cu(I) oxide so badly? What do you need it for anyway? Finally, I kinda doubt that you'll be able to reduce the copper to copper I. I think that if anything is going to happen, it will reduce all the way to metallic copper. But have a look at steel production to get an idea of the kinds of temperatures you'll be needing. Copper is not the same stuff as iron of course... but it might be interesting anyway.

Get yourself an eagle or something ... or a dog, and teach it that hunting geese it fun, and appreciated. Dogs don't get tired of chasing something that easily. I heard that in Canada, some golf courses now employ trained dogs (the same type that shepherds to keep the sheep together)... but if it's just for a relatively small patch of grass next to the house, any dog might do the trick. I don't recommend synthetic chemicals (your kids are going to be playing there too, right), and I think fireworks are going to be a mess.

I kinda like oxygen. Feels good to breathe, and without it I do think the world wouldn't be the same. A big thanks to all who can do photosynthesis!

Milk composition: http://en.wikipedia.org/wiki/Milk Soy milk composition: http://en.wikipedia.org/wiki/Soy_milk Soy composition: http://en.wikipedia.org/wiki/Soy#Protein.2C_vitamins.2C_and_minerals But after all the previous posts, I am certain that you checked these wikipedia websites already... what else do you need? You'll have to be more specific now to get more info. I am afraid that both milk and soy milk are rather complex mixtures of biological molecules, of which many are polymers. Those polymers in turn often consist of several different monomers. Then to top it off, they are both emulsions. What do you want to compare? I hope not the complete list of components? (It might be longer than the phonebook of India).

All I found was wikipedia, but that doesn't seem to give an easy method to produce it... it might give you some ideas though. http://en.wikipedia.org/wiki/Copper%28I%29_oxide

insane_alien, At what conditions did you do those measurements (temperature, and air humidity differences)? And how must faster was the object cooling down? Somehow I think that katmar's reply makes sense too... the cold air will prevent sweat from evaporating properly. This can make the tiny hairs on your skin sticky, thus preventing them from standing up. That could reduce the thickness of the thin stagnant layer of air that insulates your body.

Ah, cool... never realized that there was in a way an "activity balance", if you could call it like that. Thanks for the info / explanation. The world makes sense again.

Is 21/2 inches the same as 10.5 inches?

Hmmm.... That all sounds reasonable. Anyways... I am afraid that I still have questions... The equilibrium constant is (I copy pasted this from wikipedia): Reaction: [math] \alpha A +\beta B ... \rightleftharpoons \sigma S+\tau T ... [/math] Equilibrium constant: [math] K=\frac{{\{S\}} ^\sigma {\{T\}}^\tau ... } {{\{A\}}^\alpha {\{B\}}^\beta ...} [/math] In that formula, for example {A} is the activities of species "A". (Activity is approximately the same as "concentration", and is exactly the same (by definition) in ideal cases). The activity is unaffected by the catalyst, and the catalyst itself is not present in the formula for the equilibrium. Whenever I encounter the word "activity (coefficient)" in thermodynamics, my standard response is to stop doing thermodynamics calculations, and to open some handbook or google, and go hunting for data. I've never been able to determine an activity coefficient, and I have never really found the whole thing very practical for engineering. Anyway, can we conclude that because catalysts cannot move an equilibrium, they cannot have any influence on the activity or on an activity coefficient? (Because this is troubling me a little... the activity coefficient shows how non-ideal a system is, and I can imagine that adding a catalyst can make something more or less ideal, thereby influencing the activity of other species?) Hope I am still making sense... my goal is to learn some about this topic. It has never been my strong point. Thanks for any feedback.

For those who also wonder what we're talking about: I did a little Google search... Solvent Blue 48 is an "Amine salt of Sulfonated Copper Phthalocyanine with clean deep blue shade." From the same website: Solubility: -Acetone : 9% -Cellosolve : 9% (Cellosolve = ethylene glycol monoethyl ether) -Ethanol : 8% Applications : -Alcoholic Solvents -Spirit Lacquers -Flexographic Inks The next thing I want to know: you want to increase the solubility of this "Solvent Blue 48", in what? Ethanol? Water? Another solvent?

I wonder if they are more polluting. (Big) airplanes are actually rather clean, when you look at it in terms of pollution per traveled kilometer per person. Of course taking off (going up) takes quite a bit of energy, but after that you save because you don't use any brakes, ever. As for birds... yeah, a few will learn the hard way, most will avoid these little flying cars. They also learned pretty fast that big windturbines are bad. I wonder how noisy such a flying car is... it's probably too noisy to have millions of them flying around in cities. (That's also why flying cars are popular: in Star Wars they merely hum a bit).

I think that bad stuff happens everywhere, and we're overreacting on the Chinese situation. Just check your own clothes, computer and other stuff in the house. I bet about 50% of it is Chinese. If you want to do something about the Chinese situation, then stop buying their cheapcheap stuff! Buy the quality gear. Investigate on internet which shops guarantee that their workers are over 16 or 18, and well paid, with pensions and such. I get tired of the hypocritical view people take. China bad, Chinese products good. And perhaps you (Pangloss) never bought any Chinese stuff... this is more general. I one time went to a Free-Tibet festival with friends. In the train we found out that we were all wearing Chinese clothes, up to 50%... probably made by kids or at least by underpaid people. I felt ashamed of myself...

I once saw a Neon light with a connection for in the car. Neon lights work at high voltage (10 kV perhaps?), and cars supply 12 V. Regardless of the fact that I'm 2 yrs late with this response, I think it's worth mentioning it exists...

I still think that you have some kind of phase separation, or perhaps the opposite: two phases combining into one, because those are typically processes that can suddenly happen. One droplet extra can be enough to create a new phase. You describe a very sudden pH decrease from 7 to 3, which is strange, since you keep adding NaOH. But you are changing the polarity of the system a lot by adding the 50-50 NaOH-H2O solution. What happens to the pH when you dilute the whole thing with lots of water (like 5x the total volume of water)? By adding lots of water you make sure that everything is dissolved, and you can make a decent measurement of the pH.

a very easy construction material is polystyrene foam (that ordinary packaging material). You can "cut" it by making some piece of metal hot. Anything above 100 deg C will melt itself through the foam, so if you have some circular shapes that can be heated, that could be an easy way to make wheels. Make sure you strengthen the wheels where you attach the axis (foam is easy, but not the strongest material in the world). the car itself... I would suggest you make it as light as possible, while keeping it robust. Making things heavier is usually the easy part. Wood, or plastic (something like a lunchbox?) or again more foam can be used. I don't understand why you cannot use Lego for the body of the car. Lego rules imho, although it can become a little heavy. Finally some suggestions: if you have a lab at school, fill your balloon with helium, and see how far the car gets with that light gas. If possible, also test it with CO2.

If evaporation would have anything to do with it, I'd imagine that dry air feels colder: with less water in that air, your sweat will evaporate faster, therefore cooling you better. That's also why it feels so hot in a sauna when you throw some water on the hot stones (thereby increasing the moisture in the air: you reduce your sweating). In wet air, the water already has evaporated. We're talking about water-gas, not droplets (fog and rain are crap, and you will feel miserable and cold, there's little science needed to explain why cold liquid water feels colder than air).

Tried it for a few searches, and couldn't find any different results than Google's... I wonder if there's a real difference between a huge index and a really huge index. I mean, for a given keyword, the first hits (most linked or most relevant) will not change soon... And if you need the 2845th hit, then both search engines are not the best way to go... Anyway, I will be trying it for a bit, if only because Google already knows enough about my life.

Air resistance force goes up with a second order of the size of someone. (length x width) - frontal surface area is expressed in m2. Mass goes up with a third order of the size (it's volume) and is expressed in m3. The gravity force will accelerate both equally. The drag force however will be relatively smaller for the big guy. I don't know how the friction in wheels and bearings will go up with extra weight, but I do know that on a bike you feel more resistance from air than from any other friction... so that can all be ignored.

You're confusing me a little with your choice of words: You say that there's no obvious second phase, but it is well disperded. "Well dispersed" means to me: "2 phases, in very tiny droplets"... If you mean that there is only 1 phase, "well mixed" or "homogeneous" would be a better choice of words. Also, I am confused about the concentration of NaOH: the solution of NaOH in water is 1% wt NaOH? (In your last post, you suggest it is 50% wt NaOH?) Finally, I am confused about the particles... in your first post you write that the indicator is fully soluble... so what are the particles?

One effect: every old fashioned TV set (not the flatscreen ones) will stop working properly.

Covering 2/3 of the surface of the earth... hmm... soup? NaCl will dissolve in water in quite large amounts... so I doubt it will look cloudy.

Can it be that the addition of water is the reason? With the NaOH, you also add plenty of water, I think? I can imagine that when there is more water present, more of your (organic) solvents will release a proton... is any of those solvents an organic acids perhaps? (Like acetic acid?) The protons need a "host" (a water molecule) to form the H3O+ ion. I also want to ask if there is any phase separation? It is not uncommon that a homogeneous mixture forms two phases when more water is added. If there is a phase separation, that could be a good explanation of a changing pH value... because all the concentrations will also suddenly change.

The vapor pressure of water at low temperatures means that the water concentration in air is <1%... I agree that the specific heat capacity (Cp) and heat transfer are the factors that seem to be of importance here. The heat capacity of water vapor is about twice that of air (weighted average of N2 and O2). But that means that the overall difference of the Cp of dry air and wet air is about 1%, given its low vapor pressure... To increase the mystery, I'll give some numbers: The heat transfer coefficient of water vapor is 16 W/(m K) The heat transfer coefficient of air is 24 W/(m K) I looked up some equations for heat transfer... and I conclude that one factor that I didn't mention myself, and that I haven't seen here yet is the diffusion coefficient of gases. But, that doesn't seem to be the one either: the diffusion coefficient of water in air at 25 deg C is 25.6E-6 m2/s, while that of oxygen is 20.6E-6 m2/s. The difference is not very big... Perhaps it's just psychology, not physics that makes that air feel colder?

Here's one that has been bugging me for a while now: In my tiny country (that nice little swamp at the end of the river Rhine) the winter months are crap. Usually above zero degrees (Celcius) and wet. The air humidity is generally at 90% or so. Why does wet air feel so cold? In fact, it feels less cold when it is -1 degrees, because the air is generally a lot dryer... is it me or is that tiny fraction of water really responsible for a major difference in heat transfer? At 5 degrees the vapor pressure of water is about 10 mbar, so the volume (or molar) fraction of water in air is <1%. How can it have an effect that I can really feel? The Cp value of water vapor is twice that of dry air... but that cannot be the difference. Is the heat transfer so much better perhaps? I can hardly imagine that.