Hunter's Moon Posted August 31, 2010 Share Posted August 31, 2010 I use the asynchronous Chemistry class that Tammy Moore teaches on VHSG. I had lots of trouble with conversions before I saw how she did it. She used an acronym: King Henry Doesn't Believe Dogs Can Meow. King-Kilo Henry-Hecto Doesn't-Deca Believe-Bases (Liter, Meter, Gram) Dogs-Deci Can-Centi Meow-Milli. Say you need to convert 12, 321 grams to kg. It takes 3 spaces to move over so the answer is 12.321 kg. For those familiar with this trick, can you please tell me why it doesn't work with Mega as well. I needed to convert 10,000,000 mg to Mg so I decided to just take on M to the acronym before the word King. I counted how many spaces it would be (7) and my answer was: 10. The book though, says the answer is .01Mg. Can anyone tell me why that is and why the trick didn't work with Mg? I had to do it the way I don't understand: 10,000,000mg/1*.001g/1mg*1Mg/1,000,000g. The reason I don't understand the above problem is because I never know where to place the numbers. I know where the units need to go because I know mg needs to be crossed out and replaced with Mg, I just never put the numbers in the right spot and then the whole problem is wrong. If someone knows why the conversion trick doesn't work with Mg and they know how to do conversions the scientific way above, can you please explain? Thank you. Quote Link to comment Share on other sites More sharing options...
regentrude Posted August 31, 2010 Share Posted August 31, 2010 She used an acronym: King Henry Doesn't Believe Dogs Can Meow. King-Kilo Henry-Hecto Doesn't-Deca Believe-Bases (Liter, Meter, Gram) Dogs-Deci Can-Centi Meow-Milli. Say you need to convert 12, 321 grams to kg. It takes 3 spaces to move over so the answer is 12.321 kg. For those familiar with this trick, can you please tell me why it doesn't work with Mega as well. I needed to convert 10,000,000 mg to Mg so I decided to just take on M to the acronym before the word King. I counted how many spaces it would be (7) and my answer was: 10. The book though, says the answer is .01Mg. Can anyone tell me why that is and why the trick didn't work with Mg? I had to do it the way I don't understand: 10,000,000mg/1*.001g/1mg*1Mg/1,000,000g. The reason I don't understand the above problem is because I never know where to place the numbers. I know where the units need to go because I know mg needs to be crossed out and replaced with Mg, I just never put the numbers in the right spot and then the whole problem is wrong. If someone knows why the conversion trick doesn't work with Mg and they know how to do conversions the scientific way above, can you please explain? In the acronym, the factor between two consecutive ones is always 10. However, the factor between Mega and kilo is one thousand! Mega means one million times the basic unit. So you need three places more. (You would encounter the same problem with micro, which is one millionth, and hence a factor of 1,000 from milli.) The unit coversion is really not that complicated if you remember that what you need to do is multiply your quantity by ONE in order to not change it. So the factor you multiply with must be ONE. You need to know that there are 1000mg in 1g. Then your conversion factor is 1000mg/1g, or 1mg/0.001g. You already know that the unwanted units must cancel to leave only the wanted ones, so this tells you which way round to put the fraction in. The best way to learn unit conversion is to memorize what the prefixes mean: kilo=1,000, hecto=100, deka=10, deci=1/10, centi=1/100, milli=1/1000. And Mega=1 Million. Quote Link to comment Share on other sites More sharing options...
Hunter's Moon Posted August 31, 2010 Author Share Posted August 31, 2010 In the acronym, the factor between two consecutive ones is always 10.However, the factor between Mega and kilo is one thousand! Mega means one million times the basic unit. So you need three places more. (You would encounter the same problem with micro, which is one millionth, and hence a factor of 1,000 from milli.) The unit coversion is really not that complicated if you remember that what you need to do is multiply your quantity by ONE in order to not change it. So the factor you multiply with must be ONE. You need to know that there are 1000mg in 1g. Then your conversion factor is 1000mg/1g, or 1mg/0.001g. You already know that the unwanted units must cancel to leave only the wanted ones, so this tells you which way round to put the fraction in. The best way to learn unit conversion is to memorize what the prefixes mean: kilo=1,000, hecto=100, deka=10, deci=1/10, centi=1/100, milli=1/1000. And Mega=1 Million. Thank you for helping me with both problems. I really appreciate it! Quote Link to comment Share on other sites More sharing options...
Halftime Hope Posted August 31, 2010 Share Posted August 31, 2010 ahem, Stephanie, :) I't good to "see" you. I've been wondering how you are doing and I surmised that you've been heads-down studying! :) How are you? How's it working out? Sending good wishes and much admiration your way! Val P.S. Sorry for jacking your thread! Quote Link to comment Share on other sites More sharing options...
Hunter's Moon Posted August 31, 2010 Author Share Posted August 31, 2010 ahem, Stephanie, :) I't good to "see" you. I've been wondering how you are doing and I surmised that you've been heads-down studying! :) How are you? How's it working out? Sending good wishes and much admiration your way! Val P.S. Sorry for jacking your thread! Lol, nice to "see" you too. I'm doing good and I'm loving homeschooling. I took a break half of July and all of August until Monday because we had some house guests so I just decided to start with the Public Schools here. But getting started again hasn't been hard and I'm enjoying myself. Still getting used to kids in school while I'm at home. Thank you for asking :) I hope you're doing good as well. :) Quote Link to comment Share on other sites More sharing options...
swimmermom3 Posted August 31, 2010 Share Posted August 31, 2010 Hi Stephanie, I am glad to hear your experience so far has been positive. I have linked you to Donna Young's site for an explanation on unit multipliers. My middle child tried to dance around learning them, but admitted defeat this year and buckled down and mastered them. The last time we worked on them, his comment was, "I can't believe I avoided this for so long." Yes, his mother couldn't believe it either.:D Keep working on mastering it and come back here with your questions. Like regentrude suggested, you should memorize the prefixes. Give yourself a vocabulary root lesson and you will have a valuable tool. Take care and have fun! Quote Link to comment Share on other sites More sharing options...
Hunter's Moon Posted September 1, 2010 Author Share Posted September 1, 2010 Hi Stephanie, I am glad to hear your experience so far has been positive. I have linked you to Donna Young's site for an explanation on unit multipliers. My middle child tried to dance around learning them, but admitted defeat this year and buckled down and mastered them. The last time we worked on them, his comment was, "I can't believe I avoided this for so long." Yes, his mother couldn't believe it either.:D Keep working on mastering it and come back here with your questions. Like regentrude suggested, you should memorize the prefixes. Give yourself a vocabulary root lesson and you will have a valuable tool. Take care and have fun! Thanks for the site and advice! I really appreciate it :) Quote Link to comment Share on other sites More sharing options...
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