jsharr ★ Posted January 22, 2015 Share #1 Posted January 22, 2015 Ryan weighed in his car last night. How come it is heavier upside down? I think it must have deflated a bit on its wheels. Maybe the same thing happened to the Patriots? I wonder if the balls had the right pressure upside down? Link to comment Share on other sites More sharing options...
Square Wheels Posted January 22, 2015 Share #2 Posted January 22, 2015 It's the scale. We have a lot of scales in our lab. Some of the poor quality ones will do this. The difference between the two is likely outside of the scales capability. Try again putting it on on the same exact spot. Link to comment Share on other sites More sharing options...
jsharr ★ Posted January 22, 2015 Author Share #3 Posted January 22, 2015 It's the scale. We have a lot of scales in our lab. Some of the poor quality ones will do this. The difference between the two is likely outside of the scales capability. Try again putting it on on the same exact spot. I bought that scale for the pack years ago. It is much better than the one we had. Do you know if it is a decent scale? It seems very accurate and very sensitive. If you lean on the table, the scale will change. I have considered building a cradle for the cars so they sit on they scale the same way each time and then zeroing the scale with the cradle installed. Link to comment Share on other sites More sharing options...
Former member Posted January 22, 2015 Share #4 Posted January 22, 2015 Try replacing the battery. I have some past experiences with gram scales giving inconsistent readings. :whistle: 1 Link to comment Share on other sites More sharing options...
jsharr ★ Posted January 22, 2015 Author Share #5 Posted January 22, 2015 Try replacing the battery. I have some past experiences with gram scales giving inconsistent readings. It runs off AC power...... If you look at the top right corner of the first picture you can see the power cord. Link to comment Share on other sites More sharing options...
Former member Posted January 22, 2015 Share #6 Posted January 22, 2015 It runs off AC power...... If you look at the top right corner of the first picture you can see the power cord.the photos are about 1.5" on my phone, so that was hard to see. 1 Link to comment Share on other sites More sharing options...
Patriots Butt Posted January 22, 2015 Share #7 Posted January 22, 2015 I'll lend you my scale. Link to comment Share on other sites More sharing options...
Square Wheels Posted January 22, 2015 Share #8 Posted January 22, 2015 Scales aren't cheap. I'm sure the one you have is fine. I suggest placing the car on the scale the same way each time. Link to comment Share on other sites More sharing options...
jsharr ★ Posted January 22, 2015 Author Share #9 Posted January 22, 2015 Scales aren't cheap. I'm sure the one you have is fine. I suggest placing the car on the scale the same way each time. As I recall that one was hundreds of dollars and very precise. Also bought the 500g calibration weight for it. It is just very very sensitive and you are correct that one must put the item to be weighed on the scale the same way each time. Link to comment Share on other sites More sharing options...
Johnny Come Lately Name Posted January 22, 2015 Share #10 Posted January 22, 2015 I wonder if the balls had the right pressure upside down? .....I'm thinking that's a question I don't want the answer to, Link to comment Share on other sites More sharing options...
jsharr ★ Posted January 22, 2015 Author Share #11 Posted January 22, 2015 .....I'm thinking that's a question I don't want the answer to, One would have to work mighty hard to blow smoke up your ass, no? Link to comment Share on other sites More sharing options...
Square Wheels Posted January 22, 2015 Share #12 Posted January 22, 2015 As I recall that one was hundreds of dollars and very precise. Also bought the 500g calibration weight for it. It is just very very sensitive and you are correct that one must put the item to be weighed on the scale the same way each time. Sounds like a pretty good scale balance. For the calibration weight, did it also come with a glove and is it stored in a box? You should not touch the weight with your skin, you will increase the weight of the weight over time. Link to comment Share on other sites More sharing options...
jsharr ★ Posted January 22, 2015 Author Share #13 Posted January 22, 2015 Sounds like a pretty good scale balance. For the calibration weight, did it also come with a glove and is it stored in a box? You should not touch the weight with your skin, you will increase the weight of the weight over time. No on both accounts. Link to comment Share on other sites More sharing options...
Square Wheels Posted January 22, 2015 Share #14 Posted January 22, 2015 No on both accounts. I won't matter much, unless you are doing home chemistry. Your 500g weight is no longer 500g, and if you use that to calibrate your balance, then that is no longer accurate either. How much are we talking? Small parts of a gram. Link to comment Share on other sites More sharing options...
KrAzY Posted January 22, 2015 Share #15 Posted January 22, 2015 The reason for the difference is easy, The car on it's wheels has more oxygen below it giving the car more lift when it drives, by being upside down you reduced the amount of flow below the car making it heavier. 1 Link to comment Share on other sites More sharing options...
Pokey Posted January 23, 2015 Share #16 Posted January 23, 2015 How much does the standard column of atmosphere weigh? At what barometric pressure? Maybe a storm front came rollin and tumblin by. Link to comment Share on other sites More sharing options...
Thaddeus Kosciuszko Posted January 23, 2015 Share #17 Posted January 23, 2015 Sadly, the scale you purchased is unsuitable for the task. It says right on the front virtual measurements, so that's what you're getting. None of the supposed measurements indicated by the display are real - they're only virtual. Link to comment Share on other sites More sharing options...
Road Runner Posted January 23, 2015 Share #18 Posted January 23, 2015 What are we talking about here? 5/1000 of a ounce? Surely you aren't concerned about a reading difference of 0.005 oz. In my experience, that much variability would be expected in such an uncontrolled measurement as described here. Link to comment Share on other sites More sharing options...
KrAzY Posted January 23, 2015 Share #19 Posted January 23, 2015 What did your car weigh in as a block of wood? I just weighed our block and tires to be 4.95oz.. I'm thinking I might need to add a little weight when we are done cutting them today and after the sanding. Link to comment Share on other sites More sharing options...
jsharr ★ Posted January 23, 2015 Author Share #20 Posted January 23, 2015 What did your car weigh in as a block of wood? I just weighed our block and tires to be 4.95oz.. I'm thinking I might need to add a little weight when we are done cutting them today and after the sanding. Did not weigh just the block, but that sounds about right. We removed the majority of the wood so that we could add the weight right where we wanted it, which is just in front of the rear axle slot. If you are going to concentrate on one thing, it is filing / polishing the axles, do not forget to polish the back of the axle head, and using lots of graphite in the wheel hubs and on the axle. Link to comment Share on other sites More sharing options...
jsharr ★ Posted January 23, 2015 Author Share #21 Posted January 23, 2015 What are we talking about here? 5/1000 of a ounce? Surely you aren't concerned about a reading difference of 0.005 oz. In my experience, that much variability would be expected in such an uncontrolled measurement as described here. It is funny, but the boys all want to be as close to 5 ounces as possible. And the scale is so accurate that lots of boys and dads spend quite a bit of time adding and subtracting minute amounts of weight. Link to comment Share on other sites More sharing options...
Kzoo Posted January 23, 2015 Share #22 Posted January 23, 2015 What are we talking about here? 5/1000 of a ounce? Surely you aren't concerned about a reading difference of 0.005 oz. In my experience, that much variability would be expected in such an uncontrolled measurement as described here. Ya that's like 31/100000 of a pound or 1.41748e-7 of a metric ton. Who cares? Link to comment Share on other sites More sharing options...
jsharr ★ Posted January 23, 2015 Author Share #23 Posted January 23, 2015 Ya that's like 31/100000 of a pound or 1.41748e-7 of a metric ton. Who cares? Boys do. Since it was important to Ryan, we made it happen. Fun with a purpose. He learned some new skills and he paid attention to detail, instead of just settling for close enough. 1 Link to comment Share on other sites More sharing options...
Kzoo Posted January 23, 2015 Share #24 Posted January 23, 2015 And in the PWD .005 ounces is not good enough. We need accuracy here. Link to comment Share on other sites More sharing options...
jsharr ★ Posted January 23, 2015 Author Share #25 Posted January 23, 2015 And in the PWD .005 ounces is not good enough. We need accuracy here. We can only do so much. However, if you would care to provide us with a more accurate balance, we would gladly accept it. Link to comment Share on other sites More sharing options...
Kzoo Posted January 23, 2015 Share #26 Posted January 23, 2015 We can only do so much. However, if you would care to provide us with a more accurate balance, we would gladly accept it. WoKzoo has several antique scales I'm sure she'd let you borrow. I doubt any of them are more accurate that +- 1/2 a pound (at best). Link to comment Share on other sites More sharing options...
Randomguy Posted January 23, 2015 Share #27 Posted January 23, 2015 Boys do. Since it was important to Ryan, we made it happen. Fun with a purpose. He learned some new skills and he paid attention to detail, instead of just settling for close enough. I won the overall pinewood derby my last year as a cub scout, having taken second overall (to my brother) the prior year. My first year, I think my misshapen car finished in the lower rankings. I got a big trophy for winning, it was pretty cool. We had a scale. 1 Link to comment Share on other sites More sharing options...
jsharr ★ Posted January 23, 2015 Author Share #28 Posted January 23, 2015 I won the overall pinewood derby my last year as a cub scout, having taken second overall (to my brother) the prior year. My first year, I think my misshapen car finished in the lower rankings. I got a big trophy for winning, it was pretty cool. We had a scale. See, it matters! You remember this. We are making memories and hopefully building character at the same time. Link to comment Share on other sites More sharing options...
Randomguy Posted January 23, 2015 Share #29 Posted January 23, 2015 See, it matters! You remember this. We are making memories and hopefully building character at the same time. Link to comment Share on other sites More sharing options...
Randomguy Posted January 23, 2015 Share #30 Posted January 23, 2015 See, it matters! You remember this. We are making memories and hopefully building character at the same time. The memories are cool, as are the lessons learned. I learned very basics of car assembly, a bit about sportsmanship, a little about perceived unfair advantages (when I lost), aerodynamics, graphite, weight distribution, and taking a longer view of things (when I won). It was nice to see cause and effect in play. I did not have under-inflated tires. 1 Link to comment Share on other sites More sharing options...
jsharr ★ Posted January 23, 2015 Author Share #31 Posted January 23, 2015 that is a good video and it covers most if not all of the good stuff. The bent axles is a bit much for me. Link to comment Share on other sites More sharing options...
Dottleshead ★ Posted January 24, 2015 Share #32 Posted January 24, 2015 Link to comment Share on other sites More sharing options...
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