U-tube viscometer yog ib qho khoom sib thaj uas muaj kev sib txawv uas pab paub qhov dej yog li cas rau qhov thickness lossis thinness. Nws yog qhov yuav tsum tau siv rau cov neeg kho mob thiab cov neeg ua haujlwm uas xav paub qhov kev hloov haujlwm ntawm cov dej sib txawv, vim tias nws yog oil, water lossis syrup. Yog tias cov dej yog heev viscosity, nws yuav heev nyuaj rau kev dhau. Qhov khoom no pab peb paub qhov dej yog li cas rau kev dhau. Viscometers uas tau pab cov kev lag luam paub qhov zoo ntawm cov dej.