Ice, density

Fig. 4 Depth-age relationship of the ice cores from Fiescherhom glacier [12] and Colle Gnifetti [13, 14], Besides annual layer counting and radiocarbon ( C) dating, two types of time markers were used Saharan dust events (labeled by the year only) and volcanic eruptions (labeled by year and name of volcano). Depth is given in water equivalent. This is the amount of water contained in the ice core which is calculated using fim and ice density, respectively, both increasing with depth...

Density are swamped by the clay effect The density decrease apparent in hydrates is very small but may be distinguished from the density of water but not from ice density. However, this is a fine difference, and it should be used with the suite of other logs... 

As it can be observed in Table I, the volumes obtained from water adsorption are quite similar to the calculated micropore and mesopore volume. These results indicate that the approach considered in this study is suitable. Water adsorbs initially on microporosity (up to P/Po 0.6), as a solid-like structure. In these pores the density of adsorbed water can be considered to be similar to the ice density. On the other hand, the similar values of Vmeso and Vh2o 0.6-0.95 indicate that water adsorbs on mesopores as a liquid. 

FIGURE 2-8 Density versus temperature curve for water. Maximum density occurs at 4°C thus, stratification in a lake can occur in winter with bottom waters near 4°C and less dense surface waters closer to 0°C. In summer, if stratification occurs, the warmer water will be at the surface. Note that a given spread in water temperature conveys a larger density contrast between the waters (and hence a more stable stratification) at higher temperatures than at lower temperatures. The density of ice is much less than the density of liquid water (note the broken scale for ice density). 

Another interesting observation leads to some conclusions about the spatial distribution of the excess stress at the solid/liquid interfaces. Let us consider density profiles of the ice surface and ice/water interface compared with bulk ice density profile. In Fig. 4 we show that the ice cut forms a specific layer on the ice surface, which shows on the density profile the tendency of a small shift towards the bulk ice. When the water is in contact with the ice cut another density maximum is formed at the contact, reducing, at the same time, the initial surface stress and the shift of the top density peak of the ice cut. This implies that the first strongly smeared solid-like layer at approximately z = 20 A is responsible for the main contribution to the interfacial excess stress of the ice/water interface. 

Atmospheric precipitation, in the form of snow and ice, has accumulated continuously for thousands of centuries on polar ice caps. The snow density at the surface is about 0.3 g cm and it increases with depth below the so-called close-off depth the firn (snow with density higher than 0.4 g cm"" ) turns into ice (density 0.83 g cm ). At this depth (between 95-115 m in the central east Antarctica) air in the pores of the firn gets trapped in ice as bubbles preserving fascinating information on the gaseous composition of past atmospheres (12-16). 

Where hi is the ice s thermal conductivity, is ice density, and C-is the specific heat capacity of ice. 

Another indication of the probable incorrectness of the pressure melting explanation is that the variation of the coefficient of friction with temperature for ice is much the same for other solids, such as solid krypton and carbon dioxide [16] and benzophenone and nitrobenzene [4]. In these cases the density of the solid is greater than that of the liquid, so the drop in as the melting point is approached cannot be due to pressure melting. 

It has a higher latent heat and a greater density producing an over all cooling effect which is about twice as efficient as ordinary ice. 

Upon melting, ice loses its open structure with the "melting" of some fraction of the hydrogen bonds, and so the volume of the Hquid water decreases, reaching a minimum at 4°C above this temperature thermal expansion dominates the density. 

The physical properties of bismuth, summarized ia Table 1, are characterized by a low melting poiat, a high density, and expansion on solidification. Thermochemical and thermodynamic data are summarized ia Table 2. The soHd metal floats on the Hquid metal as ice floating on water. GaUium and antimony are the only other metals that expand on solidification. Bismuth is the most diamagnetic of the metals, and it is a poor electrical conductor. The thermal conductivity of bismuth is lower than that of any other metal except mercury. 

Fig. 4.10. The arrangement of H2O molecules in the common form of ice, showing the hydrogen bonds. The hydrogen bonds keep the molecules well apart, which is why ice has a lower density than water.

Fig. 5. Examples of ihe correlation between measured adhesive strength and (l+cos6). (a) Plot of data from Raraty and Tabor [171J for adhesion of ice to various solids, (b) Plot of data of Barbaris [172] for adhesion of a mixture of epoxy and polyamide resin to low density poly(ethylene) treated in various ways. Both figures from ref. [31], by permission.

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