Can you suggest how these symmetrical ripple marks were formed? Last week's asymmetrical ripple marks were formed by a uni-directional current. What do fossilised ripple marks tell you about current directions? Find out by downloading this activity.There are many Earth-related activities for you to try on our website. Do please let us know how you get on with any of them.
5 comments:
First of all, thanks a lot for maintaining this excellent website. Very inspirational and useful, not just for teaching, but for our own basic understanding. We all need a little fresh-up of the basic stuff from time to time.
I just have one comment on this exercise: Symmetrical Ripple Marks
The question
"What was it like to be there - when the ripple marks were forming? The pupils should describe a sandy beach or shallow sea area. The beach could be yellow (if the sand came from eroded rocks), white (if of tropical coral sand), black (if of volcanic sand) or a mixture."
I don't think the color-generalization holds. The most yellow beaches I have seen have been coral sand, and the whitest was pure Quartz. It depends a lot on local geochemistry(iron /manganese staining: orange/red, P-feldspar:pinkish/red...).
I think a better way is to ask the students what color they imagine the sand has, and ask them to motivate it. The important thing is to make them think about it; there is not a "correct answer" to sand color.
Cheers
Thank you for this comment Richard. We mentioned some sand colours and their origins as examples but, of course, it is desirable for the pupils to imagine their own colours, provided they have good reasons for their suggestions.
Did this activity with a group of future teachers at a workshop. It was a good introduction to ripples and I followed up with examples of ripple marks from local sands and asked them to try and determine flow direction on the ancient sandstones.In response to Richard from Bergen's comment, perhaps one thing is to try and link color to local sands and encourage students to think about how many colors of sand they have seen.
This is a good idea Mary, especially if the pupils can come up with reasons for the various colours.
Thank you for your comment.
Thanks a lot for sharing this interactive activity! My students enjoyed it a lot. I am looking forward for another ides from this blog. Thanks.
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