Many of these leaves were on the forest floor. They look to be from different plants. Yet they are both leaves from the common English Ivy. There are several varieties, though probably all of the common (and invasive) types have this funny characteristic. In fact, as a further surprise, I learned that the smaller, simpler […]
The name is descriptive yet misleading. The colored edges of some clouds indeed look a lot like the colored interference colors in a soap or oil film, which is what physicists call iridescence. Yet in the cloud case, the effect is due to a slightly different phenomenon—diffraction. The diffraction occurs around many tiny cloud droplets.
On a gently rippled lake, look near the boundary between reflections of land objects and sky. If you are close enough to see the ripples, you may be entertained by the wonderful patterns of light and dark as in the photo above. Lynch and Livingston* call the distorted reflections of the sky within the darker
Skypools & landpools Read More »
Just rays of light bouncing off a lake… Recently while walking along the eastern shore of Lake Sammamish, I noticed the dark jagged reflection of the hillside on the water. What’s going on with those trees in the reflection? Aren’t reflections supposed to be like mirror images? They seem very stretched out. Look at the
Reflections on rippled water Read More »
A few days ago (Mar. 28), I described the decline in frost days at the Green River station in Washington State. What about other locations? And what are “ice days”? Read on. An ice day is a day in which the maximum temperature is below (or at) freezing. It differs from a frost day in
Frost & ice days: some trends Read More »
Back in January after a dip below freezing, we found loads of hair ice in a nearby nature preserve. Having found hair ice elsewhere before, I have gained a sense for when and where it might appear. Good conditions for hair ice, at least here in the Seattle area: mornings when the ground can freeze,
The book that I’ve turned to most often over the years is Minnaert’s “The Nature of Light & Colour in the Open Air”, which describes many interesting and sometimes rare things to observe outside*. And for me the most memorable part of that book is his introduction to halos (example in the picture above): “After
At this time of year, the weather changes often. Two days back, the usual low clouds and rain were unexpectedly interrupted by clear sky. In the midst of the plain blue sky, I noticed a small thin cloud above the sun. It seemed high enough to be cirrus, though I did not know what type.
CZ (circumzenithal) arc in a drifting cirrus Read More »
Are winters getting too warm for ice? Is the “ice-watcher”, a person like me who delights in seeing swirly film frost on surfaces or hair ice from wood, doomed? Seeking an answer, I decided to count cold days. Consider the “frost day”, defined as a day in which the temperature near the ground goes below
End times for the ice-watcher? Read More »
