The platinum ring method and the platinum plate method are two experimental methods commonly used to measure the surface tension of liquids. The difference between them lies in the shape of the experimental setup and the way it is operated.

Platinum Ring Method:

In the platinum ring method, the experimental setup is a platinum ring. First, the liquid sample is placed in a closed container and a thin layer is formed on its surface. The platinum ring is then carefully placed into the liquid, making sure it is in contact with the liquid surface. Due to the surface tension of the liquid, the liquid will form two curved surfaces of different heights on the inside and outside of the ring. The surface tension of the liquid can be calculated by measuring the contact Angle between the liquid surface and the ring or the liquid height difference.

Platinum Plate Method:

In the platinum plate method, unlike the platinum ring method, the experimental device used is a plate-shaped platinum sheet. The liquid sample is placed in a closed container so that it forms a flat liquid surface. The platinum plate was then carefully placed into the liquid so that it was completely submerged in the liquid, remaining parallel to the liquid surface. The presence of liquid surface tension will cause the liquid to form a tiny bump on the platinum plate, called a liquid film. By measuring the thickness or shape change of the liquid film, the surface tension of the liquid can be deduced.

The difference between the platinum ring method and the platinum plate method

Therefore, the difference between the platinum ring method and the platinum plate method lies in the shape of the experimental setup and the method of measuring the morphology of the liquid surface. Both methods can be used to measure the surface tension of a liquid, but the choice of which method depends on the specific experimental requirements and the characteristics of the liquid sample.

In addition to the shape of the experimental setup and the method of measuring the morphology of the liquid surface, there are some other differences to consider:

Precision: The platinum ring method usually has high accuracy and can measure surface tension changes in a small range. The platinum plate method has relatively low accuracy and is suitable for a wide range of surface tension measurement.

The difference between the platinum ring method and the platinum plate method

Experimental operation: The platinum ring method is relatively simple. It only needs to put the ring into the liquid and observe the shape of the liquid surface. The platinum plate method requires ensuring that the platinum plate is parallel to the liquid surface and measuring the thickness or shape of the liquid film, so the operation is relatively complicated.

Applicability: The platinum ring method is applicable to most liquids, whether organic or water-based. The platinum plate method may not be applicable in some cases, especially when the liquid has a high viscosity or an unstable liquid film forms on the plate.

Experimental conditions: Because the platinum ring method involves the measurement of the height difference or contact Angle of the liquid, more accurate experimental conditions and instruments may be required. The platinum plate method requires relatively low experimental conditions.

The choice of which method to use to measure surface tension depends on the specific experimental requirements and sample characteristics. Sometimes, to improve the accuracy of the results, a combination of measurements or other more elaborate experimental devices can be used. The du Nouy platinum ring method has been used to measure surface tension for 40 years before the relevant measuring equipment was researched and produced. By comparison, the Wilhelmy platinum plate method is only 20 years old. However, more and more people are using the platinum plate method to measure surface tension.

The difference between the platinum ring method and the platinum plate method

This is mainly due to the following shortcomings of the platinum ring method:

1. It is not easy to measure the surface tension value of high viscosity samples;

This is mainly due to the large downward resistance of the sample above the inner side of the platinum ring

2. It is not easy to measure the surface tension value with time;

This is mainly because the platinum ring can only measure the surface tension at the point in time when the ring leaves the liquid.

3, it is difficult to maintain the accuracy of the instrument;

Platinum ring is easy to deform, and its different size will affect the measurement of surface tension.