الجاذبية المرئية

tivity the explanation for gravity is that matter bends space and so you put mass in place of space at warp space-time and objects are not feeling force of gravity they're just following the natural curvature and so this is sheet of lycra where do you get this is my old bike shorts no there's literally spandex calm you can get sheet like this if you buy the sales stuff so you don't care what it looks like right for like 20 bucks maybe less depending on the sale and so you put matter and it warps space-time and so if have another object it also warps space-time they feel that and they're attracted to each other and so that's that's Einstein's picture of gravity objects warp space-time feel that curvature and move accordingly and if you have more mass you have more mass is going to bend space-time more respond and so you put something there now it's attracted now in reality that big mass would feel the warping of space-time by the marble - right it would move little bit but we usually usually ignore that you know the earth makes the Sun move little bit but it's so small we can ignore it the moon makes the earth kind of wobble around two point three quarters of the way from the center of the earth we usually don't account for that when we're looking at satellite motion well instead of just letting go of one what if give it sideways push now it orbits now it's losing energy which wouldn't happen in the solar system right not noticeably there's some perturbations from other planets and things but this one does lose energy and spirals in if don't push it as hard it will do the lips when you study the solar system all the planets are going around the Sun the same way why is that did God decide the only life clockwise or as I'm whether he's above or below the solar system right why is everything going in the same direction well the answer is it wasn't different directions but there was preferred direction the distant form from had slight preference one way versus another and things go in the opposite way got eliminated and when it's all said and done everything is going the same way that usually that works 90% of the time and so had slightly more in one hand and another but don't consciously do that and you want to give them something spread out little yeah the wrong way get eliminated right now there also would have been you know this is where this analogy breaks down there's you know another dimension right but those things are out of the plane also that weren't near the preferred plane also got eliminated and so that's kind of cool now my students use pH et Phet simulation called my solar system and so they've seen all this on the computer and when we do this during our special relativity unit they're like he is just like the computer that's kind of cool that stretch see the Micra model sings suicide just like it learn to the computer now some things we've discovered using this I'll say it's just some larger marbles my friends with them out but they've been space time too right and so maybe you can get one thing so the earth-moon system maybe and so you see that this seemed you know you can't buy micro this big you get it in rolls and you have to sew it together I've been told to use stretchy string the stretchy thread to sew it together and so the next time do it I'll do that because it pulls and so you just little bit of thread fixes it and so in the morning when first set this up look at leaning against the table will be underneath fixing holes from last year one time my principal walked in and hear somebody in the room and I'm underneath on the middle sewing in little paws yet and then he's looking around for me and he kind of knows some of these in the room buddies there you are because what are you doing there and go I'm repairing rip in the fabric of space-time you've probably seen plastic ones of these right the Discovery Center Children's Discovery Museum in San Jose has won the Exploratorium has won sometimes they have MIT's shopping malls you put money in it but one thing you can't do with those is put two masses in and so when we went to the moon when we first started we set our spaceship so I'm going to call free return trajectory so they would go to the moon and this is hard to get down and they would come back and like figure eight and so that lets you show now of course the moon is smaller but if you look at the plots of the free return trajectory back from the Apollo program you'll see it has figure eight sort of shape and so this takes little bit of practice to be able to do the figure eight these clamps around here you can adjust it to make it tighter if it's not working so Steve and when we set this up in the morning we played around with it and actually think it was working better than usually is it's so not easy and so go through that's one year kid who read some stuff about the dark energy energy have extra and so I'm just energy what does that makes everything come apart right and so dark energy would be that stuff goes apart rather than toward it so if you work in dark energy anytime right and so go through that spiel maybe it takes me ten fifteen minutes talking with the kids you stuff they're not familiar with and then just let them play and so that's where we discovered the earth-moon thing is just let it play and they're like mr. Barth career-low and they're all excited cos they discovered that so so if you want to try it out what we do but we want to play mr. burns so see the whole thing if you buy all the parts and everything is about hundred dollars but one of my favorite days so you're gonna do it Monday right Steve don't do it but just do it once and you'll be hooked it will take little bit of cooling to put it together but I'll post the plans it takes it comes apart all the PVC pipe wrap it with bungee cord stuff the biker in that box and can carry the whole thing myself this is about the right size you can get your whole class around it pretty much smaller what one problem is reaching some of you think would have trouble with that so you get student to do it right one thing you got to watch though is some students will think to go underneath to push up and then while they're underneath somebody decides to put the big mass out and you know they get their space-time warped and so just tell me can't go under and so is general relativity in the state standards no probably the the crowning achievement of science not in the state standards can you fit it in after the star test you bet you can find some videos like you know show thing on gravity waves and then we do this and that's you know day almost day but since don't understand it myself that's plenty so let's go back into the room