Monday, 11 February 2008

Video - Sand ripple marks in a washbowl

This is the video demonstration of this activity on YouTube.
Click HERE to view the activity.


Godfrey Nowlan said...

I tried this in my kitchen at home. It is definitely important to wash the sand before conducting the activity. It might be better (but more expensive) to use aquarium sands that are already clean. I found the activity worked differently in different containers. I got the best results using containers in which the base was perpendicular to the sides. The two examples that worked best were a plastic cake box and a container for a food processor that already has a central column, so no additional containers were needed. The activity worked less well in more typical bowls where the sides are curved and inclined with the respect to the flat base. I found that some different effects could be achieved by placed containers with different cross-sectional shapes in the centre. For example, I used a mug with octagonal cross-section and an oval cylinder. It is fun to try and explain the results and perhaps would make a good extension of the activity.

Godfrey Nowlan
Geological Survey of Canada, Calgary

Anonymous said...

I think one direction circular current is not easy to realize in the natural phenomenon.In Taiwan, we can take a familiar example. During the north-east monsoon in north Taiwan, asymmetrical ripple marks can be formed by winds in sand dunes. The wind is fast enough to form undulations, then to move sand grains up the shallow backs of ripple marks and deposit them on the steeper fronts, and to give clues to the wind direction .

peng tian yin
Department of Earth Sciences, National Taiwan Normal University

Earth Learning Idea said...

Thank you Peng Tian Yin for the previous comment. We have added it to the extension ideas for this activity. These may be viewed at