Blog #2: My initial ideas about lakes acting like mirrors

In my first post, I brought up the fact that I was curious about lakes acting like a mirror and like a sheet. In that post, I showed a photo of the same lake taken from the same spot at two different times of day. After thinking about it for a while, I decided to go back and look at other photos of lakes from my trip.


The two photos below were both taken in the morning of of hiking trip around Lake Louise. The first one was shot at 7:13 AM right on Lake Louise, and the second one was shot at 7:34 AM as I was little ways up the trail to the Beehive. Once again, we see the glacial lake appearing as a mirror and then appearing as an emerald sheet.

Why I think these two situation are similar?

Based on all of these photos, I am starting to think that angle makes a big difference on whether a lake acts like a mirror or a sheet. For the photos in my first post, the sun was low in the sky when it was a mirror and high in the sky when it was a sheet. In a similar way, when I was low to the ground, the lake looked like a mirror; but when I was higher from the ground, the lake looked like a sheet. This makes me think that maybe both you and the sun have to be low in the sky to make the water act like a mirror. 

How I am making sense of this?


I know this sounds crazy, but I making sense of this like skipping stones off water. To skip a stone off water, you have to throw the stone at a really shallow angle and you have to be standing at the water's edge. You can't skip a stone by throwing it straight down or when standing up high, like on a cliff. If you throw the stone steeply down at the water, the stone simply goes into the water. 


I am thinking that maybe light bounces off water like stones skip off water. For example, maybe if the light comes in really shallow toward the lake, then the light bounces off like a mirror; but if the light comes in really steep, then the light goes into the water showing the color of what's in the lake. This would explain why the sun has to be low to ground, so that the light comes in shallow. 


I'm curious to see if I can do an investigation shining light at shallow and steep angles to see if it affects mirror-like or sheet-like behavior.

Flashlight Observations

I was really curious about whether or not moisture had an effect on whether a beam was visible or not. I got a pot of water boiling and shined my flashlight through the steam. Here's a video:

Untitled from bfrank on Vimeo.

In the video, I'm noticing how right off the flashlight you can't see a beam, but over the pot you can. It's also interesting to me that the beam doesn't appear to go all the way through the steam–it seems to end about half way over the pot.

Are you guys noticing the same things? Anything else I'm missing?

Lakes Acting like a Mirror and a Sheet

I was recently on vacation in Banff National Park, which is in the Canadian Rockies. I did lots of hiking with a friend and I also took a lot of photos. One major attraction in the rockies are the beautiful glacial lakes, which have an emerald glow to them at times. One thing my friend and I noticed was that the lakes didn't always look emerald. In the morning, the lakes seemed to act like mirrors. Below is a photo of a lake in the morning just as we began our hike to bow falls.

Clearly, in the photo you can the reflection of the mountains, the sky, and the clouds.

Below is another photo of the same lake, taken almost at the same location, but in the afternoon as we were returning from our hike.

As you can see, while the first one shows the reflection of the mountains in the background, the second one shows more of the famous emerald color. You can't see any of the reflection.

What I'm Wondering
The difference in the photos has me wondering about why the lake acted more like a "mirror" one time and then, later, more like a "sheet". In particular, I am wondering if it had something to do with it being morning and afternoon, or if it was just a coincidence and it had something unrelated to the time-of-day. More generally, why does water act like a mirror at all? Why can you sometimes see through water, but other times you can only the color of the water (e.g., emerald)? It seems weird that water could act in so many different ways.