Directions for Book Blogging

Welcome to our summer book blog! Unlike most blogs that have one blogger- everyone gets to blog about the book, To Engineer is Human, and share ideas about K-12 engineering education and the "human side" of engineering. To reply to a post, click on Comments at the bottom of the post. To start a new post, click on New Post at the top right. However, to start a new post you have to have a Google account. If you don't want to register on Google, you can send me the text for your post and a title, and I will post it for you.

Who do we have on the blog? Our book blog consists of 16 high school teachers, 1 middle school teacher, 7 elementary teachers, 4 faculty or engineering students from the University of Maine, 3 MMSA staff, and 2 DOE staff. We have a diverse and well-rounded book group which should lead to some interesting conversations. One thing to remember- the most recent post is always at the top of the blog. If you haven't been on for awhile, scroll down and work backwards.

If you start a new post you also have the option of adding photos or other graphics as well as making a hyperlink. Play around with it a bit to get to know how it works. Try a test post- you can always delete it afterwards. Also, you will notice we will build a collection of links listed on the right. Since only the person (Page) with the Google account can add these, if you have any you would like to share, just send them to me at pagekeeley@gmail.com and I will post them for you. This is the first time we have ever tried this as a blog, so we're all getting our feet wet. Don't hesitate to wade right in!

Friday, August 10, 2012

Significant Digits


“ The Significance of Significant Digits”- a reflective response to the start of chapter 15


            In chapter 15 within the discussion of the slide rule and before the benefits and risks of computer aided engineering exists 2 interesting quotes  that I like to draw from page 190.   “…We were expected to know that we could only report answers to three significant digits from our rules… answers are approximations and should only be reported as accurately as the input is known…”  I do not know how many people’s eyes glazed over at this while mine lit up. The merits of teaching significant digits within the curriculum of college prep chemistry has become questionable in my last 4 years of teaching (the previous 14 years I did not have the same issue either since I had more time each week with my students or I just had more energy and will power.)   Most high school students do not love the idea nor understand the merit of reporting to 1 estimated digit so that there is a common system of what is known and what is approximated.  I have in fact cut the time and energy spent on this topic considerably.  However, I have also had each year students smiling and explaining to me they correctly answered a significant figures question on a state test for math or some other high stakes test.

            I guess this also has such importance to me because it is such an excellent example of using STEM . Although I would like to ignore the work of significant digits in my class, it is a necessity in engineering and scientific testing.  Therefore I believe it should also be reinforced through high school physics and math classes.  I have found it listed in Maine’s math standards but not chemistry or physics –yet I will continue to be the gremlin that will mark points off when an answer is written as 3.64512g/mL when it should just be 3.65g/mL .

            Does anyone else in the SCITEC have students report their calculated answers to the correct significant figure?   Does anyone else in SCITEC have their students mark the estimated digit within the measurements they take to reinforce that there is always approximation even when they use something like a digital balance?

Posted on behalf of Sheryl O'Donoghue
 

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