----------------------------------- Mazer Sat Mar 26, 2005 8:36 pm Now you can do a physics project that ISN'T insanely boring! ----------------------------------- a-[url=http://www.solardeathray.com/]clicky-click! It seems like it would be very interesting to build. And what physics does it involve? Well, you got those light wave thingies that we were supposed to learn about... and uh, heat... I guess that was covered in class some time... and much more! To be fair, somebody did a project about YO-YOs which managed to keep me interested for a record length of time in that class. But c'mon, it's a Solar Death Ray. A real one! I make this post, targeting Massey students in particular (because I know they have to make something), but anybody else that will be doing a physics project is encouraged (indeed, "peer pressured") to see if this project would be a possibility. ----------------------------------- AsianSensation Sat Mar 26, 2005 8:53 pm ----------------------------------- yes, see, the projects this year has to do with the wave nature of light. We get to choose from a bunch of topics like LCD screens, 3D films made with polarized filters and stuff like that. So sadly, no Solar Death Ray. Btw, how fast does the SDR zaps stuff? I couldn't find that much info on it, and I was just curious, because the pictures of zapped objects were pretty entertaining. ----------------------------------- Mazer Sat Mar 26, 2005 9:57 pm ----------------------------------- It's not really a "zap"... this isn't an EM-grade RailGun we're talking about. It just focuses sunlight. Like... have you ever used a magnifying glass to burn ants? It just focuses light to a smaller point and slowly heats the thing up. Alot. Same principle here, I guess. Anyways, I never really paid attention during the whole "waves" thing (or much of ths rest), but wouldn't this involve the wave nature of light? Waves can be reflected, I know that much... right? ----------------------------------- Pickles Sun Mar 27, 2005 3:29 pm ----------------------------------- They made a huge one on Myth Busters to try to sink a ship, but they couldn't. ----------------------------------- rizzix Sun Mar 27, 2005 3:58 pm ----------------------------------- maybe they should filter out all wavelengths except one (preferable red so we can see it). and polarize the light, while focusing it at one point and redirecting them parallely in a single direction. woopdidoo. now it is a real death ray! ----------------------------------- Andy Sun Mar 27, 2005 4:21 pm ----------------------------------- why would u bother polarizing it? the first polarizing filter will decrease the intensity drastically ----------------------------------- Martin Sun Mar 27, 2005 4:59 pm ----------------------------------- I already made like infinity of those at scout camp. ----------------------------------- rizzix Sun Mar 27, 2005 5:35 pm ----------------------------------- why would u bother polarizing it? the first polarizing filter will decrease the intensity drasticallyhow else are you going to get it unidirectional ----------------------------------- Andy Sun Mar 27, 2005 7:02 pm ----------------------------------- why would that matter? as long as they're parallel to each other, it should be fine ----------------------------------- rizzix Sun Mar 27, 2005 9:37 pm ----------------------------------- dude the point is to get them parallel. ----------------------------------- Andy Sun Mar 27, 2005 10:00 pm ----------------------------------- but all the rays comming to us from the sun are pretty much parallel to each other... ----------------------------------- Andy Sun Mar 27, 2005 10:02 pm ----------------------------------- and plus, by polarizing light, you dont necessarily make them parallel to each other.. you simply make sure the transverse waves travel in the same plane ----------------------------------- md Mon Mar 28, 2005 2:10 am ----------------------------------- Polazing the light will only block out some of the waves, as would filering out specific wave lenghts. The point is to focus as much as possible, cutting out parts simply weakens your death ray... The point is not to get the rays parallel either, it's to focus them onto one point. You put you object at that point and all the light hits it, heating it up... anyway It could easily work, if for instance the myth busters had used a solid mirror instead of lots of small ones it would have nearly doubled the surface area and thus doubled the temperature :) ----------------------------------- Andy Mon Mar 28, 2005 11:41 am ----------------------------------- yea but inorder to focus them, they have to strike the mirror parallel to the principle axis ----------------------------------- MihaiG Mon Mar 28, 2005 8:43 pm ----------------------------------- i did osmething similar ingrade 5 for a project were spposed to make an oven/solar cooker that use light..mine worked i use an old satlaite dish the parabolic ones :P covered int tin foil and voila ----------------------------------- Aoi Tue Mar 29, 2005 12:55 am ----------------------------------- you guys are scarying me ----------------------------------- Mazer Tue Mar 29, 2005 10:01 am ----------------------------------- I'd go with the term "boring." C'mon, the idea here was to burn things! ----------------------------------- md Tue Mar 29, 2005 11:33 am ----------------------------------- yea but inorder to focus them, they have to strike the mirror parallel to the principle axis Nah, you just need to deform it a little. It harder to manage hen a lot of little mirrors, but for the gain it could be worth it. ----------------------------------- Andy Tue Mar 29, 2005 8:41 pm ----------------------------------- i used to have a sweeet parabolic concave mirror... cant find it... it was so nice, bought it to build an reflection telescope ----------------------------------- Aoi Wed Mar 30, 2005 11:15 am ----------------------------------- I'm beginning to understand why most girls are afraid of compsci kids ----------------------------------- rizzix Wed Mar 30, 2005 4:01 pm ----------------------------------- yep, you do. its almost always because of their poor self esteem (due to their poor intellect in comparison) :P :P ok keep those chopsticks down i was just joking ----------------------------------- jamonathin Wed Mar 30, 2005 6:51 pm ----------------------------------- I made a balloon car . . . :roll: ----------------------------------- md Thu Mar 31, 2005 12:37 am ----------------------------------- I'm beginning to understand why most girls are afraid of compsci kids Could it be because we generally like doing things that others find childish or dangerour, or just plain stupid? Although there are certainly girls who like that kind of thing... and i know who they are :P ----------------------------------- Cervantes Sun Apr 03, 2005 5:01 pm ----------------------------------- There are lots of physics projects that aren't insanely boring. I made a trebuchet. http://www.nhswork.netrulon.com/geoff/treb/hcw1-front.jpg (I don't know about the one above. I see it shifted in the middle. Wierd, do you guys see that?) http://www.nhswork.netrulon.com/geoff/treb/hcw1-side.jpg For the next one, just take out the period (.) in "c.ocked". Lousy filtering! http://www.nhswork.netrulon.com/geoff/treb/hcw1-c.ocked.jpg ----------------------------------- brenn Sun Apr 03, 2005 5:33 pm ----------------------------------- Naw, Aoi, most of the compsci guys that I know are absolutely awesome. Well, computer science and mathie guys, not just the ones here 8D And nice trebuchet. :S I do see the .. shift in the middle of the first photo, was the camera in pan shot or something? What prevents the thing being launched from being caught in the blue harness? ----------------------------------- Cervantes Sun Apr 03, 2005 6:06 pm ----------------------------------- It's got nothing to do with the camera because the pic on my computer is fine. I thought it was a screw up in the upload, but I tried it twice and it looks the same. The blue thing is the pouch, inside which is the tennis ball. As the throwing arm rotates around the axle, the sling (and pouch) rotate (whip) around the end of the throwing arm. One end of the sling is fixed to the throwing arm, whereas the other end is attached to a 'release pin', whose angle can be changed to get the correct projectile angle. So, at some point when the sling is whipping around the end of the TA, the one end slips off the release pin, and the pouch opens up. [url=http://www.ripcord.ws/howslingswork.html]It's a lot easier to explain with images. :wink: ----------------------------------- md Sun Apr 03, 2005 6:27 pm ----------------------------------- The pictures look fine... although it's kinda small :P ----------------------------------- Cervantes Sun Apr 03, 2005 6:42 pm ----------------------------------- Small? http://www.thehurl.org/show_image.php?id=727 Haha, but yeah, it isn't that big. This was my first siege engine though. I enjoyed it, so I think I'm going to make another. Bigger, possibly of a different design (a more modern one). But seriously, don't let the size of a trebuchet deceive you. These things can be [url=http://www.thehurl.org/show_image.php?id=353]dangerous! ----------------------------------- brenn Sun Apr 03, 2005 7:58 pm ----------------------------------- Thanks for explaining xD :S I don't know about the photo, in that case. And the miniature trebuchet is so cute. xD ----------------------------------- Martin Sun Apr 03, 2005 8:13 pm ----------------------------------- How the hell can a trebuchet be 'cute'? ----------------------------------- Mazer Sun Apr 03, 2005 8:32 pm ----------------------------------- You just (in this case, carefully) paint this on the side: (>^^)> "KAWAII!" Cervantes, kudos to you. ----------------------------------- md Mon Apr 04, 2005 1:52 am ----------------------------------- lol, i know just how dangerous they can be... my friend built one for a history project... it was about twice the size of the one you build, and boy did it throw stuff... i've never seen a rock get imbedded in a tree since... ----------------------------------- Aoi Mon Apr 04, 2005 2:54 am ----------------------------------- How the hell can a trebuchet be 'cute'? cute might reference to the smallness... I actually find it quite adorable too...