The paper clip is more dense than water but can rest on the surface of the water because of the water's surface tension. Evidence of water's surface tension can be seen where the water strider's legs ...
More information: Ju Ho Son et al, Selenium-promoted molten metal catalysts for methane pyrolysis: Modulating surface tension and catalytic activity, Applied Catalysis B: Environment and Energy ...
The Journal of Infectious Diseases, Vol. 35, No. 6 (Dec., 1924), pp. 526-536 (11 pages) A systematic study of the surface tension of liquid culture mediums has been made. Nine standard mediums have a ...