The metric system is so important for students to understand in the sciences. And frankly, it's so much easier to use than the imperial system. One issue I've come across when teaching is that students don't always understand what the units represent, and which unit is appropriate to use for each situation (especially when measuring length). Here is an easy way for students to realize why we need different units of measurement.
I was at Ikea furniture shopping and realized that the disposable rulers they have for free all over the store would be an awesome teaching tool. I pulled the "teacher card" and asked if I could have a bunch for my classroom. The employee was happy to give me a class set of 40. (That was enough for me to group students in 4's across my 5 periods).
For this lesson, each group will need:
I started by giving each group one of the blank measuring tapes and asked them to measure the length of the lab table. Most groups came up with answers like "1 1/2 strips of paper", or "1 3/4 strips of paper" long. Next, I asked them to take the same blank measuring tape and measure the length of their school ID. It got harder for them to estimate the length since it was so much smaller. I got answers like "1/10 of the tape." We stopped and discussed that it would be better to have a smaller measuring tape to measure the length of the the ID. I asked them "Would you get a more accurate measurement if you cut the strip of paper in half?" They said that would still be too big. Quarters? Still too big. This went back and forth until we decided that cutting the strip of paper into 10 equal pieces would be just about right. I handed them scissors and asked them to cut it into 10 equal pieces and then measure the ID again.
The opposite scenario is also true: ask them how many strips of paper it would take to measure the distance between school and their house. Students will quickly realize that the measuring tape they have is much too small. Stop and have a conversation with your students about how it is important to have different units of measurement that are appropriate to the object being measured.
Finally, I switched out the blank strips of paper with the Ikea measuring tape. Have them make observations about the tape like:
Next ask them to take the Ikea measuring tape and cut it into 10 equal pieces. It should go much smoother this time now that there are numbers! Then ask them to take the 1/10th size paper (1decimeter, but they don't know this term yet) and ask them to cut it down again into 10 equal pieces (centimeters). Repeat this one more time until you have them cut individual millimeters. (See images below)
Have students discuss when it is appropriate to use each unit of measurement. I had them match objects to each length that are about the same size. For example, the meter strip is about the length of the floor to the door handle. The decimeter strip is about the length of the palm of your hand. The centimeter strip is about the width of your fingernail. The millimeter strip is about the thickness of their school ID card.
Following the activity we took notes on the metric system and units of measurement. I think students remember the units better when they understand that everything is based on powers of 10, and can relate the units to objects. One of my favorite phrases to use in the classroom is "NO NAKED NUMBERS!" It makes them giggle (especially middle schoolers!), but students know to not turn in papers for the rest of the year that have numbers with no units.
I hope this helps you teach the metric system! If you have any other tips and tricks, leave them in the comments! Also, you might want to check out these metric system posters and puzzles in my TpT store:
Ordering class sets of prepared slides can be pricey. Want a fun and free way to make your own? All you need are some slides, clear tape, and some animal hair samples. Put a few pieces of hair on a slide and carefully cover it with clear tape. A couple tips:
(Below: Left image is human hair, Right image is cat hair)
Another way to get some unusual hair samples is by checking with your local game and fish department. In Arizona our Game and Fish department has skull and pelt boxes that they loan to schools for free. I had borrowed the skull box for my ecology unit and had my students compare skulls of different animals. While I had the box, I also plucked a hair or two off the pelts and made prepared slides. It was fun to look at mountain lion, bear, and coyote hair in addition to the everyday pets.
Have you made prepared slides for specimens other than hair? I'd love to hear about it! Leave it in the comments!
It's here! The 3rd annual week of holiday cheer from your favorite TpT science sellers! There will be different promotions every day, so be sure to check back and snag the daily deal! This year's daily deals will include:
Monday: 20% off my entire store! Click here to shop
Tuesday: Download my photosynthesis flip book for free for 24 hours! Click here to snag it
Wednesday: Have you had your eye on my writing prompt activities? They are 50% off! Click here to browse the different bundles
Thursday: BOGO free on all products under $10! Buy a product, send me a screen shot of your TpT cart, and tell me which product you would like me to send you for free! Applies to items under $10, and free item must be equal or lesser value than the purchased item. Ready for your freebie? Email me at email@example.com and please allow 48 hours for your freebie to arrive.
Friday: You really won't want to miss this deal! Click here to download some amazing resources from top TpT science sellers! This link will only work until Monday December 11th at midnight, so act quick!
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