Significant Figures are great – if you know all the rules, and can keep them straight. In my state, significant figures aren’t REALLY a part of our standards. I mean, they are, but not really, so I struggled for a while coming up with a good significant figures activity to engage my students. In NY sig figs are sort of introduced in chemistry and really paid attention to in physics, the following year. My students need to know how to count significant figures, which isn’t too terrible. My chemistry students also need to know the rules for singular calculations. But I’ve landed on a really fun activity that I use all year long to keep my students fresh on their sig figs skills!
Significant Figures Background
In order to teach significant figures, students need practice with it! I typically spend one day teaching how to count significant figures, using the Pacific-Atlantic method. It’s a really simple method! You simply write the number inside of a map of America. If the decimal is PRESENT you approach from the PACIFIC side of the number. If the decimal is ABSENT you approach from the ATLANTIC side of the number. Then you start counting at the first non-zero number. That number and everything that comes after it is significant.
Why We Need Sig Figs
What even are significant figures? They’re digits within a number that give a measurement REAL VALUE. They are not there as a result of rounding. They are confirmed numbers within a measurement. We need them as a way to determine how our measurements were taken. 1.000 is actually different from 1.0. Those extra zeroes indicate a more precise (and expensive) scale!
At the point that I’m teaching sig figs my students have already learned the difference between accuracy and precision. The students know that calculations and the numbers that we report, all the way down to how we round those numbers is important. My students have a tendency to really understand WHY we need significant figures, but it’s the HOW that gets them. (I find this is a specific issue with my students every year, so it’s gotta be something about the way I teach.)
Practice Makes Perfect
Asking a bunch of 15 year olds to do mindless calculations to get significant figures practice is a mission destined for failure. Nobody wants to do that! Not even me. Plus students are too new at chemistry to really try to tie these skills into a lab activity. My solution? Turn it into a game, of course. And on top of that, make it a competition.
Significant Figures Activity
We do a Significant Figure Race! I organize the students, using these grouping pencils, into groups of two to four (depending on class size and amount of time). Then I give them a series of very simple math problems that require good attention to the details of significant figures rules. A student answers one question and passes it to the next kid. The first answer becomes part of the second question. I tell the kids that they need to check the work of the kid before them, to make sure that their question is correct.
Then the second student will answer their question and pass to the third in the group. Then the fourth answers the final question and passes back to the first student to check the final answer. I usually have the students each have a different color pen or pencil so I can identify who wrote each answer. The group of four who answers their question series first, or the most question series (depending on what I choose) wins!
You can grab this epic significant figures activity for your classroom here! It includes 10 unique worksheets for your students to grapple with, and of course, answer keys!
Other Ways to Use This Activity
Working Silently
You could add in elements of students having to work silently. The condition of silence makes the game that much more challenging! Students have to either write out their answers, or use soem kind of make shift signing in order to communicate their ideas. Great for your first back to school cold when you’ve got a gnarly headache.
Use a Life Line
I also like allowing groups to use life lines. They can ask me to remove a wrong answer from their paper, or ask for a verification on a question that may be tough so they can move forward. When the competition is really tough, I’ve even made the life line of pausing another group’s work for 10 seconds. They have to flip their paper over and can’t work for ten seconds so other groups can speed past them.
Use All Year Long
There’s 10 versions of the worksheet, so you can choose to do this activity once a month. I like to do this to make sure that my students always stay fresh on their significant figures skills. This is super important during units like Atomic Theory and Periodic Table where you sort of take a break from doing so much math. It’s easy to lose the skills if they aren’t being used each day!
Make Boring Skill Drills More Fun
This activity turns something SUPER BORING into something fun – especially if you can award a prize to the winning group (I suggest candy or stickers). You may find that a common theme in my classroom is to trick my students into learning by changing worksheets into games. You can learn more about the test review games I play in my classroom, and how I make drill skills more fun.
