Yesterday's estimation was the roll of pennies. So Today was a roll of nickels. Interestingly the example below has 2 overestimations. Not many students mentioned the thickness of the nickel.
Students worked on comparing the surface area and volume of a square based prism (gym bag model) and a cylinder based. After consulting the standards, volume is the primary focus of the 8th grade Common Core geometry standards. I'm going to quickly make copies of the Making Matchsticks task from map.mathshell.org and give students 10 minutes on the pre-assessment.
Students made sense of how the original piece of paper folded. The perimeter was 52 so the divided by 4 since the base was a square. This example also talks about 4 congruent faces. Once again I focused on the word inside surface, face. The areas are not sides, they are faces of the 3 dimensional solid. Then we reviewed the general volume formula of V=Bh, or volume equals the area of the Base multiplied by the height.
I stressed showing your work and labeling what your calculations meant. Tomorrow we will explore the surface area then volume of a cylinder.
|Stressing the difference between inches squared and inches cubed.|
|Sample of some great student work.|
|I loved this reasoning. Sectioning it off into fourths and saying one section was 10 so 10*4=40.|
When I am on paternity leave students will complete the below task as well as analyze some other students work to justify why it represents 9 3/4.