How I Help Students with the Metric System in High School Chemistry

helping students with the metric system

Living in America, the metric system can be super foreign to students. No pun intended. Many of my students are starting to drive, and think in gallons.  They cook, and think in tablespoons and cups.  Trying to help students with the metric system is much easier said than done.  With that being said, there’s a few things I do in my classroom that I think could be helpful if you gave them a try. 

Find Out What they Already Know

This doesn’t have to be an official thing that takes a lot of time. KWL charts are so 2005.  Maybe use a Google Jamboard and have students write the terms they already know.  You could have students come to your physical classroom board and do the same thing.  Turn them to a partner or small group to discuss.  Your students have likely learned two sets of measurements – customary and metric and sometimes get them confused.  Talking to classmates can actually have them pull the metric system from deep in their memories. 

Ask them to do customary conversions

I LOVE to get my students frustrated with the customary system of measurement. Because “inch” is a four letter word in my chemistry classroom. By asking them how many pints are in a gallon, they can get pretty frustrated. Use this for good. As you have them realize there is no straightforward conversion rate (4 quarts in a gallon, 8 pints in a gallon, 128 ounces in a gallon…) they’re quickly on the metric system side. 

I don’t give them a worksheet for this.  I want the pain to come and go quickly.  I’ll usually just drop a conversion or two on my board and ask them to do this from memory. It’s pretty rare that I can get one kid to get all the answers right without the help of Google. I try to aim at volume conversions because they’re the most difficult. 

If you’re interested in length or distance metric measurements I have a good one for you. Have them “cut a piece of wood in half.” The length is 3ft, 7/16 inches. Boom, goes the dynamite. 

Assign Base Units First

Helping students with the metric system will require you to more or less start from scratch.  I do this by reminding them which base units are applied to each type of measurement.  We specifically go over the seven base units, leaving out any derived units. They usually know meter, liter, gram and seconds. I’ll introduce candela, amps, mole and Kelvin.

For the record, in chemistry we almost never use time or candela. Mole sits on the backburner until we get to stoichiometry, and Kelvin doesn’t appear until gases.

I approach this as “the unit tells you what you’re measuring and what tool you’re using.”

Prefixes for Relative Size

Then I give the students the metric prefixes from milli to kilo.  We don’t use much beyond that in high school chemistry. I indicate that small prefixes are used to measure small things, and big prefixes measure big things.  But the prefix sort of just says “hey, this is a big distance, that’s why it’s kilometers.” We talk about the difference between relative size and absolute size.  “Mrs. Reavy is taller than Simone, but shorter than Michael.” vs. “Mrs. Reavy is 5 foot 6 inches. 

I also will relate this to distance on Earth. My desk to the door, vs. my desk to my house, vs. my desk to a nearby city.  “Meter” tells you I’m measuring distance with some kind of ruler, or perhaps odometer tool.  The prefix tells you if it’s a big distance or a small distance.  Last the number tells you EXACTLY the distance. My students have always responded well to this kind of help with the metric system.  This is also great for the physical science students with the term “magnitude.” Like, “what is the magnitude of the speed of the car?” This means “tell me the number only.”

We remember the prefixes with the phrase “King Henry Drinks Unusually Delicious Chocolate Milk.”  I also tell students about other prefixes we won’t be using, like Mega, Giga and Tera, which they quickly recognize as computer storage.  We also add in micro, nano and pico as tiny units we could use if we studied chemistry more intensely. 

Show What You Know

We take all of our notes in interactive notebooks. I try to keep these things super simple. You can read more about how I fake interactive notebooks in this post.  These notebooks are great for helping students with the metric system because it’s so easy for them to flip back to.  There’s no risk of them throwing away these notes, as they’re locked in the notebook. We refer back to these notes throughout the year – especially when we get to Solutions and have to convert milliliters into liters over and over again.  At the end of this lesson, students do some practice problems.  When they’re done I give them all the answers and they have a reference to go back to for the whole year. 

Pixel Art Activity

Of course, one set of 10 practice problems won’t solidify too much. So to help students with the metric system, we do a pixel art activity.  It’s a digital activity in Google Sheets.  There’s 20 metric conversion questions that students have to answer.  The sheet is programmed to mark their answers correct or incorrect as soon as they type the answer.  If they get it wrong, they’ll know to try again or ask for help.  As they answer questions correctly, some colored blocks lift away revealing a secret image.  This is not only great for student engagement – but it’s great for studying!

Students can clear out all their answers OR make a copy of the entire Google Sheet and do the work again.  Since the sheet will immediately mark answers right or wrong, when the students are home and studying, they can do it alone! They won’t need me FOR ANY REASON because the sheet does all the marking.  If they get things right, they know to stop because they understand it. If they get it wrong, they know to head back to their notebook and reread the notes. 

Where Does this Fit in my Chemistry Curriculum ?

If you need a chemistry curriculum, I have one for you! You can get a free copy of my chemistry curriculum outline. This outline explains how I teach chemistry and the order in which I teach the units. There’s also a link to a live document of my day-by-day outline of each and every lesson I teach.

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