Teaching Measuring Weight with Non-Standard Units

Last week was super busy!  I don't know if Halloween and "trick or treating" that has me tired or if it's just the time change along with the fluctuation in temperature. 

At the first grade level in Virginia, we use non-standard units with the measurement strand of the state standards for measuring length,weight, and volume..  While the balance scales are great for weighing small items, they're not useful for big things such as pumpkins.  This year I wanted to see if I could create something to measure a large object such as a pumpkin.

I used a shelving board for my beam and put a patio block below it. I took a large bag of rice and divided the rice into equal portions in plastic bags. I had six bags of rice in all.  The rice became my non-standard units for measuring the weight of the pumpkin.  I put the pumpkin on one end of the beam and one bag of rice on the other end. The pumpkin's weight was more than one bag of rice which caused the beam to tip to the left as seen in the first picture. Then I put a second bag of rice on with the first bag of rice. This seemed to cause balance as seen in the second picture.  

The pumpkin's weight was more than one bag of rice.

The pumpkin appeared to weigh two bags of rice.  This was not exactly correct!

Finally, I added the other four bags of rice on to see if the weight would cause the beam to tip over again. It did not tip.  I determined my teacher-made seesaw was an inaccurate measuring tool. Nonetheless, it did tell us that the pumpkin was heavier than one bag of rice! Perhaps I should have used smaller units of rice per bag to cause more measuring to take place.  I was wishing for one of those old playground seesaws to test this out more but we don't have them in my location. 

Some children have exercised with "teeter toys".  When using a "teeter toy", you place one foot on each side and then shift your weight from the left foot to the right foot to cause the "teeter" to rock.  While a bit abstract, perhaps a few children could make the connection between the similarities of how the balance worked and that of a teeter toy.

I would love to hear your ideas about how to create a simple device that could weigh large objects with non-standard units.  It can't be too technical or require a lot of carpentry skills though.  Please share!

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