Significant Figures Made Easy (fixed version)
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- 1. Significant FiguresMade Easy By Miss Virginia Williams
2. ENGAGE: This section may be used as a PowerPoint, as a story being told, or as I do it, asa kind of play they act out (includingdancing around the room when they get tobe the significant numbers). 3. Once upon a time..Some friends decided to go to the hot new dance club downtown. 4. They got to the door all excited. 5. The bouncer was scary looking, but they all had identification so they werent worried at all. 6. As they showed their identification, the bouncer nodded and let eachone pass. Until. 7. The others were inside dancing, and having a grand time. Not realizing that their friends were now on their way home totally confused as to what had just happened. 8. The next day at schoolThey all met back up and the story was told.Together, they went to the library to find out what rules the bouncer was talking about. 9. What they found:1. All nonzero numbers are significant.2. When a zero is surrounded by nonzero numbers it is significant. If more than one zero is surrounded by nonzero numbers, the zeroes surrounded are ALL significant.3. When a decimal is in the number, the first nonzero number present and all the numbers after it are significant.4. When the number is written in scientific notation, all the numbers to the left of the multiply sign are significant. 10. But what does that mean? 11. They decided to work on the rules one at a time. Starting with the first rule. All nonzero numbers are significant. This is why all of us that were not a zero got to go in but the others didnt. 12. They all agreed and decided to look at rule number two.When a zero is surrounded by nonzeronumbers it is significant. If more thanone zero is surrounded by nonzeronumbers, the zeroes surrounded areALL significant.So, if we go in with those that are not zeroes in themiddle, the zeroes can come in. Like we are sponsoringthem or saying they are part of our crew.But does it matter how many zeroes are in themiddle?Nope, see it says that even if there is more than onezero surrounded, that all the surrounded zeroes aresignificant. 13. They all agreed and decided to look at rule number three.When a decimal is in the number, thefirst nonzero number present and all thenumbers after it are significant.I think I get this one. Its like if you have aline and someone in the line has a creditcard and says, I am paying for myself andeveryone behind me. The credit card is thedecimal, and the guy that is using it is thefirst nonzero number that appears in thelineup. 14. Again they all agreed and felt likethey had the first rules figured out. Now, it was time for the last one.When the number is written in scientificnotation, all the numbers to the left of themultiply sign are significant. Scientific notation is when there is amultiply sign with ten to some powerright? Yeah, and you know that bouncer wears adifferent necklace when his wife is out oftown. It means that everyone in front of himgets in free to party. They all laughed. 15. They had the rules down and were ready to see if they could followthem to get into the club. And now its your turn. Each of you will have an identification card. Can you arrange yourselves sothat the numbers you make will allow you to get into the club too?Lets try it. 16. ExploreStudents should each get an ID.IDs are single digits from 0 to 9.Have them arrange themselves to create numbers with a certain number of significant and insignificant numbers.Added challenges: Require a certain decimalplacement and/or scientific notation placements. 17. Explain: Review with guided worksheets the rules forsignificant numbers. Continue on to guided practices with usingsignificant figures to round variousmeasurements. This can take time, but one ofthe keys is to remind them that if I owe $4567and the guy says hell be happy with it to threesignificant numbers, he wont be pleased to get$457. The value must stay the same, we arejust rounding to a certain degree of accuracy. 18. Elaborate Time to take it to the next level. Usedimensional analysis word problems tohelp them figure out how to know howmany significant figures their answersmust have. 19. Evaluate: Provide word problems involving variousproblems involving the activities that havebeen done for students to show mastery ofthe concept. 20. Added note of importance: Always make sure to remind the studentsbefore they leave that no matter whatnumber they were given as an ID or whatvarious placements they were put induring the course of the activity, that theyare significant to you.