-
Posts
4,674 -
Joined
-
Last visited
Content Type
Profiles
Forums
Store
Help Articles
Everything posted by dcarch
-
So I can print out a realistic looking fish that tastes exactly like strawberries? Very nice. dcarch
-
I came up with this idea for an experiment which you may be able to do, which will show you clearly the science of atmospheric pressure between two closely attached surface: 1. Find a 5" x 5" ( or any shape with about the same surface area) piece of flat plastic disk with a handle or metal disk that is flat with a handle. 2. get a thin plastic grocery bag and Scotch tape over the the entire plastic on a flat table, making sure there are no leaks. 3. Use a straw to suck all the air out under the plastic and tape over the hole where you insert the straw. 4. It will be impossible for you to lift the disk without using over 350 lbs of force without breaking the plastic. There is no water or potato starch between the surfaces to provide for adhesion. dcarch
-
Very true, and was mentioned up thread by Scubado. If you watch carefully, the video I linked shows how the food peels away from the blade with a single-bevel knife. dcarch
-
Am I wrong? 1. Master sauce is not the same as master stock. 2. Home-made master stock can taste like leftover stock, because restaurant master stock, even 100 years old, large quantity gets used up from it everyday, and new ingredients are added everyday, so it is never too old. dcarch
-
I have no interest in reading "the best pizza". It can be a lot of fun to read "the worst pizza". dcarch
-
Atmospheric pressure is universal. There is 50,000 lbs of pressure on you all the time. Your body also has 50,000 lbs of pressure to counter act the pressure. Until you are in an airplane, if the plane is not pressurized, you will be in trouble because your 50,000 lbs will push out everywhere. You will die instantly in outer space if you are not in a pressurized suite. It is so easy for everyone to understand suction cup works because of atmospheric pressure, but apparently it is difficult for everyone to accept that as long as you have two flat surfaces in close contact it is unavoidable that you have a suction cup situation. Suction cups can be made with any material, including potatoes. Potatoes do not make very good suction cups because of the texture is not very good, however a little water will help to seal leaking air into the “cup”. Still I will not try to walk up a skyscraper using potato suction cups. Now, wait just a minute, why is that if I wet the potato slice more, it comes off the blade much easier? Well, that is because you are talking about something entirely different. As I explained, thicker water is a very good lubricant, as with skiing or skating, which is entirely on water, not on ice. Also sliding sideways is entirely different than pulling out vertical, as defined by the law of physics, it take no work to move horizontally against a vertical force. The best thing of course is to utilize the sticking to your advantage. dcarch
-
Yes, it is funny how knife makers can profit millions $$$ from selling useless anti-stick knives to the public. dcarch
-
Believe it or not, those are very important and legitimate questions. 14 lbs/in sq (rounded off) is universal, everywhere, it will not do anything until you try to work against it. As I said, there is 50,000 lbs of pressure on you body all the time, however, in the science of fluid dynamics, the pressure is also in you body to equalize the outside pressure. (you will literally explode if you are in outer space) When the food is sticking on your knife, the pressure on the food is the same as the pressure inside the food pushing out, until you try to pull the food away then you will be creating a vacuum between the blade and food and you will have to overcome the 14 lbs/sq in pressure. dcarch
-
Absolutely. If you take a piece of wet tissue, it will stick on a flat surface without falling. That is the weak force of surface tension of water acting to keep the wet tissue sticking. It takes not much force to peel the tissue off, however. Now try the same size suction cup, you will be peeling against atmospheric pressure. dcarch
-
"-----Would you be able to easily pull those two smooth pieces of glass w a little water ( special water, that would not 'boil' in a vaccum ) in outer space ?----" You should be able to. Imagine, suction cups cannot possibly work in outer space. If you have access to a vacuum machine, get a suction cup to attach to a glass firmly, then draw a vacuum, the suction cup will fall right off. dcarch
-
That too is a very interesting question, often asked by many when atmospheric pressure is discussed. The answer is the same as you, a human being, not crushed to nothing, when you are at all times subjected to around 50,000 lbs of air pressure on your skin. dcarch
-
You are absolutely correct about the 104 lbs force requires. I happened to have tried with two flat glass disks with various liquids. Again, there is no mystery about atmospheric pressure, two flat surface with a little liquid inside creates a vacuum when you try to pull them apart. Air pressure demonstrations, without the use of potatoes or even water: https://www.youtube.com/watch?v=8aud79vS_Jw https://www.youtube.com/watch?v=5tG1Zrz1mbI dcarch
-
There are many forces in nature, as I said, gravitational force is one of them for all matters, then there is electrostatic, and ferromagnetic, etc., but atmospheric is the strongest in the case of flat surfaces. Surface tension is a force, but not that strong a force compared to 14 lbs/sq of atmospheric pressure. If you add detergent to water which will supposedly destroy water surface tension, and use that in between two plates of glass, you still will not be able to pull the glass apart. Water surface tension is strong enough to form a bead. If that is so strong, it will try to form a sphere in between the glass and push the plates apart, not pulling them together. Which may be interesting to try using mercury, which is 9 to 10 times stronger in surface tension. Try using alcohol, which has much lower surface tension, between the glass plates, you will experience the same difficulty in pulling them apart. It is really very simple, think suction cups and cutting food with a shine knife surface. dcarch
-
"---Slice it, and some residue will adhere to your knife, and this residue dries very quickly.---" If you are a dare devil, I would advise walking up a skyscraper with air pressure generated by suction cups, not with two half sliced potatoes. :-) Atmospheric pressure acting on two flat plates, such as with a flat knife blade and flat slice of potato, or any non-starchy food, is a well known phenomenon. dcarch
-
“---If air pressure was the important force then water between the glass would be unnecessary.—“ That is very true. The water helps because flat glass plates are not really flat. However, if you are to use optic flat glass, so flat that when you put the two plates together you can produce Newton’s Rings, than water may not be needed. “---Starch is certainly part of the story. Potatoes stick much more than other watery veg. Around 8 minutes into this video, you can see Heston using water and potato starch to put up wallpaper. Granted, he's using a lot of starch.----“ Starch in water has no adhesion, until you cook it, then it become glue. “--So which theory is it now?----“ The two conditions are for different theories. Very thin layer (molecule thinness) of water seals the very thin unevenness of “flat” glass, thicker water layer becomes a lubricant, just like when you are skiing, you in fact are skiing on water, not on ice (that’s again another physics theory). You can slide the glass plates apart much easier than pulling them apart because according to the law of physics, you need no force to work perpendicular against the other force (How bicycle works). dcarch
-
Not true. Starch water is not an adhesive. It work better if you dip you knife in water, because thicker layer of water acts as a lubricant. It is so easy to find out the power of atmospheric pressure. Get two flat panes of glass with a thin layer of water in between and see if you can pull it apart. dcarch
-
Remind me. I am sure there are other possible forces, for instance, all matters produce gravitational force, but that is extremely weak. dcarch
-
The problem is not adhesion. In General Physics 101, there is a classic experiment you can perform. if you take two flat pieces of glass, put a small drop of water in between, and you will find that you can't pull them apart. What is forcing the glass together is atmospheric pressure at over 14 lbs per sq. in. if the panes of glass are 5" square, you will need over 350 lbs of power to pull them apart. Using two suction cups, you can "walk" up a skyscraper's curtain wall. dcarch
-
Come on! If you are a doctor, a lawyer, or an architect, people always ask you for free advice. dcarch
-
Not off topic at all. I am pointing out that noisy restaurant is not designed to be noisy because it is good for business. And I am repeating more than once: 1. retail commercial rental is extremely expensive, they have to pack as many tables as possible in the dinning room. 2. When you pack people close, the inverse square law of energy disputation works against you. Every time you half the distance, I think you increase 6 DBs (I need to check, doing by memory) 3. Sound absorption is not that effective in a small enclosure. If someone is yelling near you, you can have 10 tons of absorption around you and will do you no good. Again, all surfaces in a restaurant need to be maintained well. I am not sure what acoustic material is washable. "2-3dB is the threshold that most people can perceive a change in loudness, but a doubling of loudness is a 10dB increase, not 3. " Please read what I said. I said 3 db is doubling acoustic power, not doubling loudness. dcarch
-
"-----Also RE dcarch's comment about there not being many ways to keep noise down in a room - there are quite a lot, ----" Let me put it in another way. Yes there is very effective way to cut down noise, but there is a problem you cannot change. In the science of hearing and acoustics, the problem is that our hearing sensibility is logarithmic in response. Our hearing can detect a change in sound level every 3 dbs; however, every 3 dbs, it represents a 100% in acoustic power. In other words, if you manage to lower the noise somewhat, you need to cut the noise energy by 100%. In reverse, 1 watt of power can give you acceptable music loudness, why do you need a 500 watt amplifier? because 2 watts is a little louder, 4 watts, slightly louder, 8 watts, 16 watts, 32 watts ----------. The factors I mentioned are the most effective, but not practical ways to control noise in a restaurant environment. dcarch
-
Non-stop display of amazing dishes! Truly impressive all. Halloween is for you to do strange things to food. How was your Halloween dinner? dcarch A perfectly round smoked chicken. Not sure what this is about Pairs well with Halloween background music Kaboooocha!
- 555 replies
-
- 17
-
-
What Are You Giving Out to Trick-or-Treaters?
dcarch replied to a topic in Food Traditions & Culture
Halloween is enjoyed in many countries. dcarch -
"------the noise level is a deliberate aspect of the business model.---" I don't think so. It is about extreme real estate costs for retail space, so they pack the tables as closely as possible. It is about maintenance costs. Hard reflective surfaces are much easier for cleaning. "----Chinese restaurants that get pretty loud on the weekends when Chinese families pour in---" Table sharing is a common practice. They don't even ask you. dcarch
-
Aluminum thickness in disk bottomed stainless steel - master list
dcarch replied to a topic in Kitchen Consumer
The reason for Clad cookware is to take advantage of the durability of stainless steel and thermal conductivity of aluminum or copper. I suppose the multi-layer cladding is to offset differential thermal expansion of dissimilar metals to minimize warping. I think it is more important to consider conductivity than thickness of aluminum for a cookware. Perhaps the following test can be useful: Soak pan in 32F ice water until pan reaches 32F. Put pan on boiling 212F water immediately and using an IR remote read thermometer and measure how long it takes for the pan to get up to 212F. dcarch