Sunday, April 19, 2015

Rotational Turns of Angles

I would like to share a mathematics lesson that my students worked on last week.  We had already discussed the type of angles we needed to know:  right, acute, obtuse, and straight.  Before using a protractor, my students needed to know how to measure an angle by rotating it around a circle.  I had them focus on the fraction standards we had already completed.  I put a magnetic circle fraction cut into 4ths on the board.  Each 1/4 was one of our benchmarks to use with rotation.  We then reviewed our angles and the measurements of each.  

After a quick review of angles, I modeled the 4 circles I wanted my students to draw in their interactive notebooks.

We modeled a 90 degree angle.  Our new name was "1/4 turn."  I compared the angle to a 1/4 piece of our fraction circle.  We stood up and demonstrated the turn.

We continued each circle, one at a time, using the 90 degree angle as a benchmark.  Each time we made another turn, the students would say it was one more  1/4 turn, which was another 90 degrees.

I also emphasized the inner curves.  For example, a 270 degree angle is close to 360 degree, which is one complete turn.  Depending on how the inner curve looks, this decides if an angle is a 90 degree turn or a 270 degree turn since an angle can be turned clockwise or counter-clockwise.

I also used examples that many kids are familiar with.  For example, we discussed skateboarding.  Many knew what a 180 and a 360 meant when skateboarding.

Next, each student received an Angle
 Rotation Mat and a trapezoid. 
 We practiced making rotational turns.  

Students recorded the turns in their interactive notebooks, while...

I modeled the turns on the whiteboard.

I feel my students understood the association 
with 90 degree turns.  We called rotations by the turn and also by the amount of degrees each turn was worth.  I want my kids ready for protractors and knowing these benchmark degrees of angles and what they look like will be most beneficial.

The Rotational Angle Mat is included in my angle rotation unit.  If you would like more information about the Rotational Angle Mat, please visit my TPT store by clicking on any picture or this link:  Angle Rotation Unit.  You will be taken directly to the unit! 

Have a great week!

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