3D Shapes

I had a hard time finding age appropriate information on 3d shapes online.  I found a lot of information for high school students and beyond, for computer science and things like that also.

However, then I went back to education.com and found a few good lesson plans that were appropriate and first introduced the idea of 3D shapes and differing 2D and 3D shapes.  To me this seemed like something that would be difficult to grasp, but I think by 3rd grade students can understand.

Basically the idea is really just to show the difference between 2D and 3D shapes by example.  Circle vs Sphere, cube vs square.  Once you have begun to explain and introduced all of the 3D shapes you would like to review, the teacher can begin to show these shapes in a 3D manner, with folded papers, with real life examples from the classroom, etc.  

Following this, the class can get into counting the number of sides.  This is how you can really understand the difference.  A 3D shape has multiple sides.

There are multiple worksheets but these are just to identify the shapes and name the properly.

The bigger part of this idea of 3D shapes is calculating and understanding area and perimeter.  I thought this was more of a middle school concept but it seems that this is, in fact, an elementary lesson, specifically it seems like it is introduced in 3rd or 4th grade.

I must admit...I remember the pythagorean theory, A²+ B²=C² but is that the area of a triangle or something else.  I think I need a refresher on some of the basic formulas:

First of all - the pythagoream theorem is not the area of a triangle!  Oops.  It is the relation of the angles in a triangle, specifically a right triangle.  The sum of the squares of the lengths of the "legs" (a and b) of the (right) triangle is equal to the square of the length of the hypotenuse (c).

So, moving on...or actually, moving back, to 2D shapes, here are some formulas I needed a refresher on.  

Diameter of a circle (definition - a straight line going through a circle): D=2R (2x the radius)

Perimeter of a square (definition -  continuous line forming the boundary of a closed geometric figure): P=4s (4 times the length of a side)

Perimeter of a polygon: side + side + side + side

Area of a square: 4S (4 times the length of 1 side)

Area of a rectangle: height x width

Area of a triangle: height x width (or base) divided by 2 (a square but divided in half)

Area of a circle: πR²

This was a very boring PLP, but i needed a refresher on these calculations.  Next week I am going to get a refresher on volume, back to 3D shapes.  And maybe look at some interesting ways to teach these concepts so I do not put my students to sleep!