Memorial for a Fresnel Lens

I better write down the exciting events of my Memorial day weekend before I forget and they’re lost for eternity.

We started out Saturday by going to a high school graduation party for Kara, our niece, which was being held at my sister’s house. This was a home school type graduation thing so she was lucky enough to avoid the boring and pretentious caps-n-gown thing that most of us had to endure. Quite a few relatives that I haven’t seen in some time showed up for the event. Much greeting and exchanging of addresses, email, and business cards ensued. And while that was going on, a pile of Kara’s friends showed up dragging along assorted computer hardware for a LAN party that was simultaneously going on in some other part of the house. I popped in briefly to observe but it seemed to be primarily Windows stuff and there was much gnashing of teeth over crashing computers and problems getting them connected (well, duh). I imagine most of them will shortly arrive at college to be shown the light by Linux users and turn from their dark ways.

That evening, I got drafted into doing a lot of house-cleaning jobs by Susan in preparation for our own event, planned for Sunday. They say that men detect the presence of dirt and clutter when it accumulates to the extent that common activities are prevented (e.g., dirty dishes prevent access to the kitchen or trash blocks the front door). Women on the other hand, it is said, are so sensitive to the rays emitted by dirt that they can detect individual dirt molecules located in remote rooms of the house. These things are true. Though I can add that, over time, prolonged exposure to women seems to create an increased sensitivity in men’s cleaning senses as well.

On Sunday afternoon, we hosted a small Memorial Day event for a few relatives including my brother, a sister, her husband, and the associated niece and nephew. Susan had prepared most of the food but cooking of the meat took place on our dilapidated outdoor grill. (note that this was not a barbecue – no barbecue sauce was involved. Grilling and barbecuing are two different, often mutually exclusive, things – sorry, a pet peeve of mine.) Anyway, knowing that kids love to set things on fire, I enlisted their help with the grill. And, afterwards, I brought out my 12″ fresnel lens to impress them with how easily sunlight could be used to cause small flammable objects to burst into flames. I attempted to explain how the flat fresnel lens worked while the kids performed empirical tests on the fire-resistance of a variety of common backyard objects including wood, dry leaves, and lawn funiture. Eventually, I tossed some chickens and hot dogs (for the kids) on the grill and managed a final product that was neither raw nor charred. A good time was had by all.

Monday, we had planned to go to the Dallas Artfest. We showed up in Fair Park all prepared and discovered a lot of workers disassembling empty tents. Hmmm… got the dates wrong, it ended Sunday! Oh well, we needed a day off.