This month Oliver and I are studying Geology with Daily Wonder Home Learning. This week we’ve been learning about the earth’s layers and decided to do a scaled drawing. We had fun (I think) figuring out the math to scale the earth down to fit on our page. This is how we did it.
To calculate what each section of our drawing of the earth’s layers would be, we first needed to create a scale to figure out what 1km would be equivalent to.
For example, our paper size in our Learning Portfolio is 300mm (30cm) high and we knew we would need to leave about 30mm for a title. So we wanted to draw a scaled drawing that was 270mm high.
We used these measurements for each layer of the earth:
Inner Core: 1,250km
Outer Core: 2,200 km
Continental Crust: 45km
Oceanic Crust: 10km
We added all these up and got 6,405km
Then we divided the total km by the total mm of space we had on our page: 270/6405 and got a measurement of 0.042mm
So our scale became:
1km : 0.042mm
And then to calculate each layer we took the actual km of each layer and multiplied by 0.042
Inner Core: 1,250 x 0.042 = 52.5mm
Outer Core: 2,200 x 0.042 = 92.4mm
Mantle: 2,900 x 0.042 = 121.8mm
Continental Crust: 45 x 0.042 = 1.89mm
Oceanic Crust: 10 x 0.042 = 0.42mm
And then we drew it. We really liked this exercise, not only because it provided an amazing math lesson, but also because it put into perspective just how little of the earth we live on and how much earth is beneath our street.