Nano-extensional rheometer

For measuring rheological properties of a liquid sample, the sample is attached to two sample attachment surfaces opposing each other in a pulling direction. The sample attachment surfaces and the liquid sample attached thereto are arranged in a field of view of a light microscope and imaged onto an electronic camera by means of an objective lens of the light microscope. One of the two sample attachment surfaces is pulled away from the other one in the pulling direction, while a plurality of images of the sample attachment surfaces and the sample attached thereto are registered with the camera. For different distances of the two sample attachment surfaces, both a diameter of the liquid sample in a middle between the two sample attachment surfaces and the respective distances of the two sample attachment surfaces are determined from the images registered with the electronic camera during the step of pulling.