mvp23 Posted January 23, 2007 Share Posted January 23, 2007 Ok. I have this chemistry question that my proffesor gave to us just for fun. Why does ice float in water? He wants mathematicall prove. All I know is that Ice has less density than water that`s why it loats but how can I put that in numbers. P.S. I asking this simple quiestion because I am horrible at chemistry. Link to comment Share on other sites More sharing options...
BigRog Posted January 23, 2007 Share Posted January 23, 2007 The reason why ice is lighter than water is that a certain mass of ice occupies more space than the same mass of water. This is related to “hydrogen bondingâ€. Hydrogen bonding A water molecule is composed of two hydrogen atoms (H) and one oxygen atom (O). The atoms of hydrogen and oxygen are bound by sharing their electrons with one another. This bond is called a “covalent bondâ€. However, since oxygen atoms pull electrons more strongly than hydrogen atoms, the oxygen atom in a water molecule has a slightly negative charge and the hydrogen atoms have a slightly positive charge. So adjacent water molecules are attracted to one another through the slightly negatively charged oxygen atoms and the slightly positively charged hydrogen atoms. This interaction is called “hydrogen bondingâ€. Hydrogen bonding is much weaker than covalent bonding, however, this type of bonding has a large total effect because there are so many hydrogen bonds. Structure of ice and water Ice has a diamond structure due to the hydrogen bonding. Water does not have such an orderly structure, but water molecules are squeezed close to one another because of the hydrogen bonding. Take a look at the actual structures of ice and water. The red balls represent oxygen atoms, and the while balls represent hydrogen atoms. Ice Water There is more space in ice than in water! This is the reason why ice is lighter than water. Therefore, ice can float on water. i know this is not mathematically but i just hope this helps you to the understanding of why it does float. Link to comment Share on other sites More sharing options...
RaptorQuiz Posted January 23, 2007 Share Posted January 23, 2007 lol. bigrog - I found that same website with those same grafx after searchin google for 30 seconds as well. however - no mathematical proof is provided there. It's hard to find anything good. Density and bouoncy are keys. Link to comment Share on other sites More sharing options...
mvp23 Posted January 23, 2007 Author Share Posted January 23, 2007 That`s what I kinda had in mind but when it comes to puting this into nubers I have no idea. I think I need density of both but how do get density of water? Link to comment Share on other sites More sharing options...
Kccitystar Posted January 23, 2007 Share Posted January 23, 2007 lol. bigrog - I found that same website with those same grafx after searchin google for 30 seconds as well. however - no mathematical proof is provided there. It's hard to find anything good. Density and bouoncy are keys. from Wikipedia: Ice has a density of 0.917 g/cm³ at 0 °C, whereas water has a density of 0.9998 g/cm³ at the same temperature. Liquid water is most dense, essentially 1.00 g/cm³, at 4 °C and becomes less dense as the water molecules begin to form the hexagonal crystals of ice as the temperature drops to 0 °C. (In fact, the word "crystal" derives from Greek word for frost.) This is due to hydrogen bonds forming between the water molecules, which line up molecules less efficiently (in terms of volume) when water is frozen. The result of this is that ice floats on liquid water, an important factor in Earth's climate. Density of ice increases slightly with decreasing temperature (density of ice at −180 °C (93 K) is 0.9340 g/cm³). Link to comment Share on other sites More sharing options...
BigRog Posted January 23, 2007 Share Posted January 23, 2007 i knew all that because im in chem ap this year its just easier to google then to type out an explanation yourself Link to comment Share on other sites More sharing options...
KidCavalier23 Posted January 23, 2007 Share Posted January 23, 2007 the density of water is 1 i think, I cant remember was like 3 years ago since 8th grade Link to comment Share on other sites More sharing options...
mvp23 Posted January 23, 2007 Author Share Posted January 23, 2007 Does any body know how to put that into equation?(at least into some kind of mathematicall equation or furmula) P.S. Thanks for help Link to comment Share on other sites More sharing options...
kgbaseball Posted January 23, 2007 Share Posted January 23, 2007 .917 < .9998 = flotation! There's your mathematics. Link to comment Share on other sites More sharing options...
mvp23 Posted January 23, 2007 Author Share Posted January 23, 2007 .917 < .9998 = flotation! There's your mathematics. That`s seems very eazy but how would I calculate density of ice/water. .917 < .9998 = flotation!(very cool idea) Link to comment Share on other sites More sharing options...
Timp Posted January 23, 2007 Share Posted January 23, 2007 That`s seems very eazy but how would I calculate density of ice/water. .917 < .9998 = flotation!(very cool idea) Well, the density formula is: Density=mass/volume To prove this you can do a sort of experiment I suppose. Get a chunk of ice, get the mass and volume of it, and then divide mass by volume to get the density. You can do the same thing for water, but it's density is commonly accepted as 1. Link to comment Share on other sites More sharing options...
ronmexico Posted January 23, 2007 Share Posted January 23, 2007 In terms of an experiment. You take a block of ice, with a known mass, and drop it in water, and measure it's displacement. You take an amount of water, with a known mass, and drop it in water. See how it doesn't create any displacement, other then to the ratio of 1:1. You have your experiment... Link to comment Share on other sites More sharing options...
closetogenius Posted January 23, 2007 Share Posted January 23, 2007 u probably could argue the density of water is a constant, so that way u don't need measure it's mass and volume of the water.... if you don't know the mass of some volume of water, weigh a beaker (probably on a triple beam or another instrument), then pour the water into the beaker, and reweigh, the difference is your mass of the water. and the beaker should give u the volume of the water anyway. Link to comment Share on other sites More sharing options...
ronmexico Posted January 23, 2007 Share Posted January 23, 2007 u probably could argue the density of water is a constant, so that way u don't need measure it's mass and volume of the water.... if you don't know the mass of some volume of water, weigh a beaker (probably on a triple beam or another instrument), then pour the water into the beaker, and reweigh, the difference is your mass of the water. and the beaker should give u the volume of the water anyway. I only said that you have to measure the density of water, just for the validity of the experiment. I understand that the water density is a constant, because ths water that you are pouring in, is the same as the water you are later pouring in. Link to comment Share on other sites More sharing options...
MarkB Posted January 24, 2007 Share Posted January 24, 2007 You could hand in ".917 < .9998." typed in 28-point bold font as your whole report, and strictly speaking, you should get a pass from it. You've proven it mathematically. If you want to elaborate, you could state the densities of water and ice, but quite honestly, I wouldn't go into much more detail than that. Your professor wants facts and mathematical proof, give him facts and mathematical proof and you should be given a pass. Link to comment Share on other sites More sharing options...
eber Posted January 24, 2007 Share Posted January 24, 2007 It's all about density and buoyant force. Without practically typing out and giving you the answer, everything you need to figure it out for yourself should be here: http://www.ac.wwu.edu/~vawter/PhysicsNet/T...uyantForce.html :google: Link to comment Share on other sites More sharing options...
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