Specular reflection

More help needed.( I think I should actually start another QA blog!)

Took kids out for an evening walk yesterday. The half moon was still very bright and Toothless noticed the reflection of trees in the creek near home. I explained all about reflection and told him what he sees in the water is an example of specular reflection.. He was pleased with the explanation. ( and boy was I pleased!)
Then he wanted to know
“But mama, the water in the creek is moving and the reflection is constant, unlike we saw the reflection of the mountain in the still lake when we went camping. How does that work”
Half knowledge is never good. ( and I tried to google all the physics site the whole day before posting this query. Now I am full confused. Did we see the shadow or reflection yesterday? I just can’t find the answer)

5 thoughts on “Specular reflection

  1. What you saw was specular reflection indeed.

    The waves in the creek was not “wavy” enough to create diffuse reflection (another reflective phenomena).

    So that evening there was little wind and the water flowed “quietly”

    Does that make sense?

  2. cnfsd: Thank you for the prompt reply.. At least it is a relief to know that I actually said the right thing to my son( I am still reminded every now and then, how yaya didn’t get 100% for her grade 1 maths home work when we were in M’sia because her mama decided to help her!)

    Now coming to the question.. There was no wind, but the water was swift flowing and I can’t seem to draw the graph of reflection because the surface isn’t smooth and the objects didn’t look skewed..How do I do it?

  3. You said there was no wind. That was the point. If there was, the ripples will diffuse the light.

    Your point of surface not being smooth may not be a correct observation. It was reasonably smooth even when the water flowed swiftly.

    I said it flowed quietly. Now if you pour water from one container to another with same speed for a long time (say 10 liters assuming that you don’t shake and concentrate on not spilling), you can see that it flows swiftly but in a smooth manner most of the time.

    I hope this answer doubt and it instantly took me to my college days of physics phew! I can’t touch those books again 🙂

  4. hello, hope you remember me. i had lost touch with you and your accounts last year… around jun 2007. had finished my phd (ya, am also a dr now haha), went to india, got married, then came to italy. since you used to update quite frequently, i had a lot to cath up and was wondering how would i do. so last week i copied your writeups for an year and then printed and read them at home. that was fast! went through all your emotions, wished i could talk to you. will be in touch from now on. yours was/is the only blog i have been constantly reading.

    do you have a compilation of all your posts until now, in some file, in the order? if so, could you send to me, i would like to print it for my sarah. if i try to copy, i have to read in the reverse order..

  5. Cnfsd: oru rakshayum illa..They don’t agree to my explanation and I have ended up buying GCSE grade 12 physics book.. Nall kalthu padichirunnenkil ee vayasam kalathu kashtapedantayirunnu…

    Rocksea: oh my goodness.. So good to see you..Before I forget.. Congratulations( marriage and PhD) and my regards to your Sarah.
    About the whole thing in a file? I wish i had.. I just don’t know how to save the whole thing in word, as I type the blog directly in the blogger each day

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