Water is one of key connections on the earth. Many scientists consider that in it life arose. It is unique. For example, it is the only liquid which compresses at decrease temperature, and it is very important feature. Some of its properties are abnormal. Values of thermal capacity, a superficial tension, viscosity strike. One of the most interesting features is observed in change of density.
It is required to you
- Reference book of physical quantities, calculator.
Instruction
1. So, all long ago not a secret that substance density, whether it be liquid or strong aggregate state, it is possible to calculate as weight divided into volume. That is experimentally to determine density of ordinary liquid water, it is necessary: 1) To take a measured cylinder, to weigh it. 2) To pour in it water, to record the volume.3 occupied by it) to Weigh a cylinder with water.4) to Calculate the difference of masses, having received at the same time the mass of water.5) to Calculate density by the known formula
2. However scientists noticed that values of density differ at different temperatures. But most surprising under what law there is a change. Still scientists of the whole world puzzle over this phenomenon. No who can solve a secret and answer a question: ""Why the value of density when heating from 0 to 3.98 increases, and after 3.98 decreases?"" Few years ago the Japanese physicist Masakadzu of Matsumoto assumed model of the structure of molecules of water. According to this theory, in water certain polygonal microformations - witherites which in turn, prevail over the phenomenon of lengthening of hydrogen communications are formed and squeeze water molecules. However, this theory is still not confirmed experimentally. The schedule of dependence of density on temperature is given below. To use it it is necessary: 1) To find value of temperature necessary to you on the corresponding axis.2) to Lower a perpendicular on the schedule. To note a point of intersection of a straight line and function.3) From the turned-out point to draw the line parallel to temperature axis, on density axis. The point of intersection is also required size. Example: Let the water temperature of 4 degrees, then density, after construction, be equal 1 г/см^3. Both of these values are confidants.
3. For determination of more exact value of density, it is necessary to use the table. If there are no data at necessary to you value of temperature, then: 1) Find values between which there is required. For the best understanding, we will consider on an example at once. Let water density be necessary at a temperature of 65 degrees. It is between 60 and 70.2) Draw the coordinate plane. Set an abscissa axis as temperature, ordinate axis as density. To note on graphics points known to you (And yes B). Connect them direct.3) Lower a perpendicular from value of temperature necessary to you on the piece received above note it as a point of Page 4) Note points of D, E, F, as shown in graphics.5) it is accurately visible Now that triangles of ADB and AFC are similar. Then the ratio is fair: AD/AF=DB/EF, therefore: (0.98318-0.97771) / (0,98318th)= (70-60)/(65-60); 0.00547/(0,98318th) =21.96636-2kh =0,00547kh =0,980445sootvetstvenno water density at 65 degrees equals 0.980445 г/см^3Данный a method of finding of value, is called an interpolation method.