## Tuesday, March 6, 2012

### WEIGHT a minute!

My students have been working on a weight unit.  We cover grams, kilograms, ounces, pounds, and tons in this unit.  The first activity the students completed involved understanding grams and finding benchmarks to help them remember "about" how heavy a gram is.  Of course, my favorite benchmark is a large paperclip.  The activity was divided into 3 parts.  It took about an hour to complete.
Before we began the activity I introduced my class to the concept of grams.  They held tiny gram weights and my favorite gram, a large paperclip.  Next, my students brainstormed other items that might weigh about an gram.

Each group received a balance scale, a basket full of items to weigh, and a recording sheet.  The purpose of the activity was to order the items from the least to the greatest weight.  The first part of the activity was for students to hold objects in their hands and compare the weight of each item.  They wrote their answers on the recording sheet.
Part 1

The balance scales were used for the 2nd part of the activity. Students used the same items but, compared each on the balance scales instead of in their hands.  They recorded their answers in the 2nd column of the recording sheet.
Part 2

The 3rd step involved using large paperclips.  The students placed 1 item at a time on the scales and balanced each item with paperclips.  The idea was to become familiar with associating large paperclips to grams.  They used the 3rd column of the recording sheet to write the number of paperclips used.
Part 3

I threw in an extra challenge.  The heaviest item was a roll of calculator tape.  The box of 100 paperclips was not heavy enough to weigh the calculator tape.  My students had to problem-solve to find a solution to weigh the calculator tape in paperclips without actually having enough paperclips.  All groups eventually realized that if they used other items they already knew weighed a certain number of paperclips, they could successfully find the weight of the calculator tape.
Challenge

Click on the link below to download a FREE Recording Sheet.  The Recording Sheet is divided into 3 sections.  You decide what 5 items you want the students to weigh.  (I use a pencil, small eraser, small bag of rice, small bag of beans, and a roll of calculator tape).  As a challenge, place one item with the other 4 that cannot be measured with all the paperclips.  Your kids will have to problem solve this item and hopefully conclude that they will need to use other items already weighed to help calculate the number of paperclips needed for the larger item.  (I store each group of 5 items in a plastic gallon baggie for easy use next year).