**The Overview**

I implemented this MARS lesson on 2D representation of 3D objects because I felt like I had not done a good job on covering the topic in the past – plus I thought that the way they teach it using vessels of water would be a natural segway to volume, which was the next topic I was to cover. Overall I very pleased with student engagement during the lesson and I felt like they came away with a deeper understanding and appreciation for the different surfaces of a 3D object.

The basic idea is that students are to sketch what the surface water looks like in a vessel as the vessel fills (or empties) with water. An example of that is pictured above where students were suppose to draw the surface water as the water filled up the cylinder. The second part of the lesson is a matching activity, matching the water vessel with the surface water pattern. They then make a poster that highlights and defends the decisions they make. Then a member of each group goes to another group to compare solutions. Lastly, there is a worksheet that is very similar to the opener that each student completes individually. That worksheet serves as a nice post assessment for the lesson to see how much the students have learned.

**The Advice**

– Having models of the shapes for students to look at is extremely helpful. The effectiveness of this lesson would have been decreased significantly if I had not had models. I wish I had more – I was basically running around to students who were struggling and giving them the model (yup, only 1 per shape).

– It helped me describe to the students that a sphere is composed of an infinite amount of circles, the biggest of which is called the great circle and has the radius of the sphere. The sphere is the first vessel of water that the students work with.

– Expect students to not initially see that as the sphere empties, the surface water starts small, expands, and then ends small again.

– Next year I will not have each pair split up after they create their poster. Rather I will combine two groups of two into a group of 4. At that point I will have that group come to a final conclusion as to what they are matching. I didn’t think the students did any signficant error correcting when the original group of two split up.

**The Goods**

– It’s all here. I created no new worksheets for this one. The only extra material required is stuff for the posters.

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