Finger test

The finger test or the finger test is a collective term for a large number of basic methods for the investigation of material properties that are widespread in many professions. Either the effect of a substance on the senses of the finger , the sense of touch , temperature or the perception of pain , or the behavior of a substance when the finger or fingers are acted upon is considered. In many cases, finger tests represent a simplified form of testing that would otherwise require special measurement technology or diagnostics.

General

Touching your finger is a simple temperature measurement or estimate.

Food and cooking

To assess the freshness of fish or the cooking level of meat and the like, the tissue is pressed and its consistency is assessed or its elastic behavior is observed after printing. In the case of asparagus , you can see the juice leak by pressing the end of the cut. The pulp of eggplants and other fruits or vegetables can also be assessed by pressure.

Soil science

Based on DIN 19682-2, soil samples can be roughly classified into different types of soil during the site survey by working with the fingers (kneading, rolling out, ...) and observing the behavior of the soil sample {see finger test (soil) }. A more precise determination of the cohesiveness , malleability and graininess can be made by comparison with standardized samples. The calibration of one's own sense of touch with reference samples, however, requires the reference samples to be carried with you and is therefore more likely to be carried out in the laboratory than during the survey.
The crunch sample is a special case of the simplified examination of fine sand fractions in a soil sample . The sample is not assessed with the fingers but with the teeth.

material testing

The roughness of a surface produced by machining or the point or sharpness of a blade can be assessed by running your finger over it.
In the case of contact adhesives , a finger test is used to check whether the adhesive film has flashed off for a long enough time. The adhesive film is touched and observed whether it pulls threads and how high the remaining immediate adhesion is.

Printing technology

The question of whether a signature is authentic or reproduced by machine can in some cases also be checked with the finger. Two properties of handwritten signatures are used: they cannot be touched or smudged. However, there are special printing processes for smearable signatures.
The adhesion of the printing ink ( tack ) can also be tested with a color sample between two fingers. The toughness of a paste-like printing ink is assessed using the distance at which the thread breaks. A similar test can be done with a spatula inserted into the paint without getting your fingers dirty.

Medicine and nursing

Finger test is the English name for a sensor attached to the finger e.g. B. in oximetry .
Finger test is also the short, imprecise name for the Phillips finger test to differentiate a first-degree pressure ulcer from reddening of the skin from another cause.
Finger samples are a special case for assessing the patient's coordination . Neither is anything examined with the finger, nor is its effect observed, but the patient's handling of his fingers is observed. A distinction is made between the finger-finger test and the finger-nose test .