Name: Shawn
Estimating absolute zero using a ballon用气球来估计绝对零度
Introduction介绍:
Jacques Charles was ascientist and ballonist. 雅克•查尔斯一个科学家和气球专家。 Charles’s law was written by him. 查尔斯规律是由他写的。 Charles’s law, Boyle’s law and Gay-Lussac’s law from the conbined gas law. 查尔斯规律、玻意耳定律和Gay-吕萨克定律都来自于混合气体定律。The three laws in combination with Avogadro’s law can be generalized by the ideal gas law. The Charles’s law states that the volume V increases with the kelvin temperature T for a fixed mass of gas at comstant pressure.(see fig.1) Mathematically, this is written as V T, then V / T = constant, where V is the volume, T is the temperature in Kelvin. The “constant” is the gradient of the graph. Using any two point on the straight line we can find the gradient. Suppose there two point on the line are (V1,T1) and (V2,T2) respectively. The constant can be calculated with the formula . The gradient and coordinate are able to help us know the straight line. Then we find the coordinate of any point on the line include the intersection of x-axis. The intersection of x-axis is just the absolute zero, but no real gas behaves like an ideal gas at near-zero volume and temperature. Therefore, by measuring the volume and the temperature the gradient of this line and the absolute zero can be calculated. The aim of this experiment is to estimate absolute zero using a ballon by this method. 本实验的目的是通过这种方法用球囊来估计绝对零度。
Experimental实验:
There were ballon, beaker and themometer. 准备好气球、烧杯和themometer。 100ml cold water put into the beaker. 将100毫升的冷水倒入烧杯中。The temperature(T1) measured by the themometer. The ballon put into the water in total. The volume increased, and the value of the volume recorded. 100ml hot water put into the beaker. The temperature T2 measured by the themometer. The ballon put into the hot water and the volume increased too. The final volume recorded(see fig.2).
Results结果:
The temperature T1 was 12℃ and the temperature T2 was 72℃. 温度T1为12℃，温度T2为72℃。The original volume of cold water and hot water both 100ml. The final volume of cold water was 226ml, and the final volume of the hot water wad 253ml.
Discussion讨论:
We have known the value above. 我们已经知道上述数值。
The value of the ballon can be calculated about the cold water.球囊的数值可以用来计算有关冷水的数字。The volume of the ballon is 226―100 = 126ml. The volume of the ballon in the hot water is 253―100 = 153ml. Therefore, we can think of a graph(see fig.3). The fixed mass of gas in the ballon, the volume V increases with the Kelvin temperature T. then we look the change easily. So (12 , 126) and (72 , 153) are two point on the straight line. The gradient is the constant from Charles’s law. It can be calculated using . m = = 0.45. The other formula can help you find the straight line which is V V1 = m (T T1). Simplify it we get the equation V = m (T T1) + V1. Let the V is equal to zero, because the aim is to find the absolute zero. Putting (12 , 126) and 0.45 into the formula. Then 0.45 (T 12) + 126 = 0. At last, we find T = 268℃.
T is equal to 270K(2 sig.fig). The best value of the absolute zero is 273K. So value I calculated is very good.
Conclusion结论:
The gradient was 0.45. 该梯度为0.45。The absolute zero I calculated was 270K, and the best value was 273K.我计算的绝对零度270K，最佳值是273K。