2008 Goal: postponed...
Currently: ? species
The uni knot is versatile, easy to tie, and strong. Use it to tie on hooks or join two lines together with the double uni knot. Works great for tying dissimilar lines together or a leader to braid. For tying a braid backing to heavier mono or even a leader to braid the Red Phillips knot is faster and smaller.
The Lake Drums Explained
What's That Noise? The drums and guns of the lakes.
Long a local legend, many have heard them on both Cayuga and Seneca Lakes, but nobody can say what causes them. Described as distant cannonfire or booming, an unforgettable sound for those on the shores of the Finger Lakes, the lake drums (or lake guns) have been a mystery for years. One night last summer, however, the ol' lightbulb switched on, and I believe I've got a few answers.
Earlier this particular day, I'd been studying the weather forecast thoroughly to decide on a fishing excursion. This was a warm early summer day, with a chance of convective thunderstorms, otherwise, calm and beautiful weather. A few storms pass the area at some point, and in the evening I go fishing down at the park. It's after dark, and within an hour or two, I hear the drums. Never thought I'd hear them!
So why do I think I know what happened? Well, that evening a very strong temperature inversion was setting up over Cayuga and the Finger Lakes. There were also the distant thunderstorms. You've probably heard that sound travels further at night- this is due in part to radiative cooling, and an inversion can really enhance that process. On a clear night, ordinary radiative cooling will leave the air near the Earth's surface cool and dense, while the air in the atmosphere above is warmer. The densities of these air masses are different, too, and this is what matters here.
As sound, in this case distant thunder, travels through the atmosphere, it encounters this density difference and is refracted toward the cooler and denser air at the Earth's surface. If the temperature inversion is strong enough, sounds can be bent entirely back to the earth.
The refraction occurs as the sound wave passes through the temperature and density gradient. The cooler, denser air slows down the wave, while the section traveling in the warmer air speeds along, overtaking the slower section. Since the faster sound is in the warmer air above the Earth's surface, the sound wave is bent back to the ground. (Ex. see figure w/ storm.)
Over lakes this effect can be especially pronounced and most fishermen have experienced this phenomenon. Ever hear voices with nobody in sight but for a boat a mile away? This most often occurs from late evening to early morning, when the air is warmer than the lake. The principle is the same! The cooling effect of the lake on the air, and associated density change, causes sounds to travel further. The surface of a still lake reflects sound well, and any 'escaping' sounds are bent (by refraction) back down toward the lake.
This can also lead to sound focusing and amplification. An example is the semicircular dome. One fella standing against one wall whispers "hello". Another guy standing in the middle of the dome hears nothing, while a third man on the far wall hears "hello" quite clearly! The sound is redirected and focused in certain spots. I think this exact same thing occurs with the lake drums.
The drums, or guns, are most often heard on warm, still, summer evenings. Evenings ideal for both summer pop-up thunderstorms and temperature inversions! My basic theory on the lake drums is that distant thunder is essentially 'focused' on the lake. A wide-scale area temperature inversion would help carry the sound of the thunder in the atmosphere, and a 'cool pool' of air over the lakes themselves focus the sound such that we hear drums or cannonfire.
We are all familiar with the rumble of far away thunder. It is generally low and long, and the further away the lower the pitch of the thunder. Long wavelength sounds travel further than short wavelength sounds, so as the storm passes and moves on, the sound of the thunder becomes a low rumble. Eventually the sound is gone and 'heat lightning' can be seen. Heat lightning is nothing more than a thunderstorm too far to be heard but within sight, the lightning flashes visible over the horizon. The lake guns occur when the storm moves even further away, out of sight. If conditions are right, the thunder from that storm will arc through the atmosphere and return to Earth on the shores of the Finger Lakes, where dwellers of the lakeshores will scratch their heads in wonder.