CaptainPanic

The bottle is just too heavy. You can calculate this yourself: 1. Measure the weight of the bottle. 2. Look up the density of air (hint: about 1.2 kg/m3) 3. Calculate the weight of the air inside the bottle. If the weight of the bottle is more than the weight of the air inside it, then replacing all the air by hydrogen won't make it float.

It's the internet. It has a weird preference for cats.

Speculations is also a forum where people come with the desire to be the next Great Inventor or the next Great Scientist, solving all the problems of the world with one brilliant idea. We aren't beating the living daylights out of the people. But we do have a simple set of rules that say that you must use the Scientific Method.

Kudus for coming up with a workable solution, instead of just complaining. I am not sure I agree with the proposal though: Nobody on the interwebs says an ad is from a third party. As iNow said, this is common knowledge. Almost all advertisements and banners are maintained in the same way. [edit] "Collusion" is an add-on for Firefox, which will track all the advertisers (and all your other browser history), and then display it in a nice graph. Quite interesting, really.

I am no expert, but here is how I think it works: There are advertising agencies. Various companies can go to these companies, and have a bunch of banners made for their products. They pay the advertising agency. Various websites (like SFN) can go to the advertising agencies, and say they have a spot for a banner. The advertising company pays them a little to have that banner on their site - regardless of what the banner is about. The advertising agency chooses what will be on the banner, not the website. SFN have nothing to say about this. Banners have a number of standardized sizes. So, the banners can be changed easily. In the old days, they would just have the same banner for every visitor. But now, some smart (and annoying) software monitors your interests, and tries to show you banners that you may be interested in... to be more effective. So, some piece of software thought you might be interested in intelligent design. So, when you see a website for healthy lifestyles with a McD's advertisement, it is not that website that does the advertising. And it is not McD's either. It is the advertising company. If you visit a website, your browser gathers data from multiple addresses, and combines that into a single picture on your monitor. The advertisements are not even stored on SFN's server! SFN have nothing to do with it. All we can apparently do is request that some advertisements are not used.

All the comments that Enthalpy wrote are very helpful. I totally agree with his post. So, practically your idea has many problems. You cannot answer the question of how many Watts of power you can get. Speaking purely theoretically, you could extract all the heat in a matter of seconds, and a lot of power. However, then soon the temperature difference between water and air would become the same, and it would stop. So, the question is how fast the sea and air can "replace" the water and air, to maintain the temperature difference. And that depends on things like the weather and the tides, and will be very specific for the location, and I cannot answer that here. So, if you have a patch of ocean available for generating energy, I would agree with Enthalpy that you should build a wind turbine. It's also good for the bio-diversity.

I cannot judge the beauty of the wind turbines. Personally, I think they are pretty, but then again, the Netherlands has a long history with wind mills. Biodiversity is however increased where the windparks are built. Here's an article that says that new species emerged at a Dutch wind park in the North Sea. Biodiversity increases. Also, here is a table of how humans kill birds. Wind turbines are just negligible. Cats are the biggest bird-killers, but power lines and cars also kill many millions of birds, while wind turbines kill mere thousands. In other words: cars kill more than a thousand times as many birds as wind turbines. So, while beauty is in the eye of the beholder, there are no signs that wind turbines are actually bad for the sea life. On the contrary: it is probably beneficial.

This is theoretically possible, but practically batteries cannot store nearly enough energy that this makes any sense.

Yes, this is possible. A solar panel + ion thruster would be a feasible way to power a space ship. I googled around a bit, and found at least one satellite, called TacSat-2, that has exactly that (launched in 2011)... so your idea is actually already being used. In the list of specs, you should search for the Hall Effect Thruster.

! Moderator Note I am (temporarily?) closing this thread, so everybody can cool down a bit, and the moderators have the time to read all your posts and see if it should be re-opened. There are far too many large-font, bold replies, and far too many discussions on who's done what, and too little about the science.

Has anyone noticed any server trouble lately? It seems that some pages load really slowly, but I am not sure if this is a problem on my end of the line, or on the server side.

I agree that beauty is an opinion... but it seems that what we think beautiful in people is something like an average of all people. I think beauty (of people) can actually be defined quite exactly.

Bubbles of gas rise in water, because it is lighter than the water. So, to you it may seem like the bubble goes up, but it actually also the water falling down. It is not like the gas is not attracted by gravity. It just has a lower density. If you sit on a seesaw, and a very heavy person sits on the other end, you will go up. But you do not go up because gravity stops working... but a heavy person has more mass, so the force he exerts on your seesaw is just larger. And although this isn't a perfect analogy to gases, it's a bit similar at least.

I think they still have a higher chance to be successful here than on some random other forum. We may have loads of scientists who don't believe their BS, but we do generate a lot of relevant keywords that will attract Joe the Google Searcher.

We have a lot of discussions on ID and other religion vs. science topics... So, if these guys advertise here, these are likely very effective advertisements, because we draw traffic through Google hits. So, yes, they may pay us a little to advertise... but from their perspective this is money well spent. I am not sure I am happy that we are providing a valuable service to the creationists... then again, I am not sure it is easy to do something about it, as some bot decides what you see. Some bots even know your search history, and will target you individually... so, michel123456, maybe you just spent a lot of time on our religion forum, and the bot thinks you might be interested. I have luckily never seen that ad.

I don't know why I even responded in the first place. Popcorn, I just want to announce that you win. We have a whole bunch of formulas that perfectly predict what will happen in almost any case. Even if you would be right... why would anyone be interested to change all the books, formulas and whatever? They work. And why wouldn't the only difference be that we add two minus signs? One for the gravitational constant, and one in the formula where we apply that constant? Oh, please don't take this the wrong way, but I will also probably not respond to your next posts anymore (I already lost interest). I have been pushed away by the gravity of your claims.

Gravity is pulling, but buoyancy can cause stuff to go up in another direction. Also, if enough pressure is generated, you can make things go against gravity. If you take a straw, and blow some water through up, and make it go up... then gravity isn't pushing it away, it is you who blows upwards. Same with a volcano, except much larger.

! Moderator Note Suzidemello, We appreciate that you are trying to help, but please do not end your posts with a commercial link. Companies generally have sufficient means to do their own marketing, and do not need the help of our forum. Also, this thread is from 2009, and you add little extra information (wikipedia was mentioned before). It does suggest that your only purpose here is to post that commercial link. This is your first and last warning. Next time you will be banned as a spammer.

! Moderator Note SolidWater, I'd normally ban a post like this on sight as spam... but I am curious if this is a genuine post, because I cannot believe that a large chemical company like Air Liquide would employ spammers to push an app. Still, as by our rules (section 2.7), I have removed the link. However, if you can prove you're not a spam bot, and if you would like to introduce a good topic for discussion for which we'd need your app, then I might consider to place the link back. I think that big chemical companies have sufficient financial means to do their own marketing. They don't need our forum.

My first guess is that you just created a sugar solution, in which some micro-organisms started to grow. It can just have dropped in from the air. Life can be quite contagious. My second (and as far as I'm concerned less likely) guess is that it could be a type of wax, which forms an emulsion over time... but it is really just a guess. Plants can contain waxes and other hydrophobic/non-polar components, but these may differ from plant to plant. But I would expect that those would precipitate out quicker (or not be in your water solution at all after running it though that column). Maybe you should do a specific literature search about the specific type of bark you have? I wonder if bark contains any proteins that you could wash out so easily? Protein solubility can change with small changes in pH. I think it should be relatively straightforward to see if it is alive: just feed it a bit more sugar. If it keeps growing, it's alive. If not, collect it and run it through a GC/MS.

There is no right or wrong about an opinion. You cannot be sure of an opinion. You can only be sure that you have an opinion, but you cannot prove that the opinion is right, or it ceases to be an opinion and becomes fact. So, no, I am not sure.

Sabre was good enough for a jet fighter in 1947... maybe it's good enough for your bike? Although a "sabre" is a weapon, not a cat. You have to add the "tooth" bit to give it a purr.

You could of course use the wikipedia page about "List of reptiles of Canada"? It sounds rhetorical, but it isn't. Answer: Greenland (Denmark). I have no idea, sorry. There are many dinos and other prehistoric animals.

Here's a list of drag coefficients (wikipedia). I'd go with the value for the cyclist or the skier. It enables you to calculate that the drag force is about 300 N (rough back-of-the-envelope-calculation). At 60 mph, you're going about 27 m/s. Power = Force * velocity = 300 * 27 = 8.1 kW, or about 11 hp. Please note: this calculation is very rough... I did some rounding of the numbers. However, I still stand by my point of several years ago: I think you'll all struggle to get that kind of power in a shoe on wheels.

Ophiolite, for your information (and eveyone else's), the mods are keeping an eye on the posts by Devonte, and it is our expectation that it is a bot, or at least a cheap spammer... so far no commercial links though. I do not think he's a troll. A troll would have to write something slightly more controversial to get our attention. A troll feeds on replies... this is almost the opposite of that: a post so empty of information and opinion that it might go unnoticed if the average member of our forum wouldn't have a brain the size of a planet.