Science

Water erosion

http://www.scienceteacherprogram.org/earthscience/img1A.jpg (water erosion exemplar)

http://thumbs.dreamstime.com/z/water-erosion-23409011.jpg (water erosion like stream table)

http://www.havasiwf.org/wp-content/uploads/2013/02/erosion-channel-island.jpeg (water erosion from river running to the sea)

Wind

http://upload.wikimedia.org/wikipedia/commons/0/09/Im_Salar_de_Uyuni.jpg (ventifact)

http://upload.wikimedia.org/wikipedia/commons/b/bb/Utah_Rainbow_Arch.jpg (arch example)

http://peter-mulroy.squarespace.com/wind-erosion/

Ice

http://www.geologyclass.org/igneou15.jpg  (exemplar ice erosion)

https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiJuTlpBM__-DF741EqhSlu-uLJ-0I99IgXfAeCfTrBuXCggiyDfb0jGl0FIR2C8sD35lFkw4KHLsunE6S8thPKIHeATdEDGYmj5h1gsiUuR42LrzlGzd8lUb0dZqCavctBqUkpkSgDDGeE/s1600/CIMG6774.JPG  (Lake Willoughby) 

http://upload.wikimedia.org/wikipedia/commons/f/f6/Smugglers_Notch(fromSouth).jpg  (smugglers notch-ice)