BS 21 S Rothrock and R. Fraser and A. E 10 , Mauer and L. Hidnert and W. Shapiro, D. Taylor, and G. Sparks and C. Can, R. McCammon, and G. London A , 72 ADS Google Scholar. Kittel, Introduction to Solid State Physics , p. Water can exist as a solid ice , liquid liquid water and as a gas steam.
At temperatures below 0 0 C, water exists as a solid, occupying a bigger volume. When heated, it expands just like any other solid up to 0 0 C. At 0 0 C, ice melts at constant temperature. Beyond 0 0 C, water contracts further up to 4 0 C. Above 4 0 C, water expands like any other liquid. This behavior of water is described as anomalous, unusual, or irregular. The variation of volume with temperature and density with temperature when water is heated is illustrated by the graphs below:.
During cold weather, the temperature of lakes and ponds drops and water contracts, becomes denser and sinks. A circulation of water is thus set up until all the water attain maximum density i. If further cooling occurs below 4 0 C , then any water below 40C will stay at the top due to its lower density. At 0 0 C, ice forms on top and this acts as an insulator to the layers below.
Hence the warmth underneath can sustain aquatic life and thus the aquatic animals and plants can survive there. Ice has a slightly lower density, about 0. The rest and a bigger portion of the ice rests under water. This is called an iceberg. Icebergs pose a great danger to ships as the submerged parts cannot be seen easily by navigators. Water sometimes finds its way into cracks within the rocks.
When such water freezes during cold weather, it expands forcing the rock to break into smaller pieces. This is very important for agriculture as soil is formed. At times the water flowing through a pipe may freeze when it passes through a cold region.
The water thus contracts, expanding and this may lead to pipe bursts if expansion allowances were not catered for. Kirjaudu Luo tili. Activity 6. The following are some of the commonly used thermometers: 6. The liquid used in this thermometer should posses the following qualities for the thermometer to be effective: Be easily visible Expand and contract uniformly Have a wide range of temperature i.
The table below compares mercury and alcohol as a thermometric liquid: Mercury Alcohol Has high b. Methylated spirit can be used to sterilize the thermometer after use.
Example 6. Expansion in liquids can be demonstrated by the set up below: Liquid When heated, the level of the liquid in the glass tube first drops and then starts rising. Air It will be observed that the level of water in the tube drops and if warmed for a longer time, bubbles are observed escaping from the end of the tube in water. The variation of volume with temperature and density with temperature when water is heated is illustrated by the graphs below: 6. Icebergs Ice has a slightly lower density, about 0.
Weathering of rocks Water sometimes finds its way into cracks within the rocks. Bursting of water pipes At times the water flowing through a pipe may freeze when it passes through a cold region. Computer Studies. FORM 1. In pipelines expansion compensators in the form of built-in pipe bends are provided. Overhead lines for the power supply must be designed in such a way that the wires do not break in winter and have sufficient distance to the ground in summer.
The basis for the calculation of these and many other constructions is the thermal coefficient of linear expansion. When storing liquids, a specified maximum filling level must be observed. Above the liquid level a space remains free, which absorbs the volume fluctuations.
The calculation of such problems uses the volume expansion coefficient. The terms derive from the fact that most substances expand when heated. The three most common temperature scales are Fahrenheit , Celsius , and Kelvin. You can see that Celsius degrees span the same range as Fahrenheit degrees. Thus, a temperature difference of one degree on the Celsius scale is 1. The definition of temperature in terms of molecular motion suggests that there should be a lowest possible temperature, where the average microscopic kinetic energy of molecules is zero or the minimum allowed by the quantum nature of the particles.
Experiments confirm the existence of such a temperature, called absolute zero. An absolute temperature scale is one whose zero point corresponds to absolute zero. Such scales are convenient in science because several physical quantities, such as the pressure in a gas, are directly related to absolute temperature.
Additionally, absolute scales allow us to use ratios of temperature, which relative scales do not. The Kelvin scale is the absolute temperature scale that is commonly used in science. The SI temperature unit is the Kelvin , which is abbreviated K but not accompanied by a degree sign.
Thus 0 K is absolute zero, which corresponds to The size of Celsius and Kelvin units are set to be the same so that differences in temperature have the same value in both Kelvins and degrees Celsius.
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