Wednesday, March 6, 2019

Last post I talked about shapes. In this post, I want to explore volume. This was a topic that was difficult for me as a student so I really wanted to review it and spent quite a bit of time reading and practicing. I found a few really great resources to help explain how to find the volume of an object.
From what I read, starting with a cube makes it easier for the students to associate the shape to the equation. I think it would be helpful to also have manipulatives for them to build and measure. One page had an example of using sugar cubes...though I'm sure students would love that...I think that having a class that energized would be a unique experience I'm not sure I want to have!

How to find the volume of a cube or a rectangular box of tissues

Volume of a Box 



 

Volume= l x w x h

When trying to find the volume of a box we have to multiply length x width x height
So if our box of tissues was 10 inches long, 4 inches wide and 3 inches wide we would have the equation 10x4x3=120. For the area of a box, it doesn't matter what number is multiplied first, the sum will be the same.

Volume of a Cylinder 


Volume = πr2h

The formula to find the volume of a cylinder is similar to that of a cube because you are using multiplication. The big difference is that you are using the radius squared as well as π, two numbers that students might be less familiar or apprehensive using. 

The equation we would use is 3.14 x radius x radius x height so if our cylinder has a radius of 4 inches and a height of 6 inches we would have the equation 3.14 x 4 x 4 x 6= 301.44.


Volume of a Cone





Volume = 1/3πr2h

Now, we have to change things up a bit when we get to the volume of a cone and do some division! We also can use the Pythagorean Therum to find the slant, pretty cool stuff! The equation we would use is very similar to the one we used to find the volume of a cylinder with the important addition of division, 3.14 x radius x radius x height÷3

Math Joke of the Week: 

Q: How do you make one vanish? 
A: Add a 'g' to the beginning and it's gone!

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For my last post, I wanted to explore why a rectangle or square can have the same area but a different perimeter. This is a trickier concept...