the

The Apple as Planet Earth

I want you to pretend that this Apple

represents our planet okay if the Apple

represents the earth how much of the

Earth's surface about is covered with

water

more than half yeah

it's about three four seven about 75

percent a little less than that but all

you future mathematicians if I'm gonna

get 3/4 of my Apple I'm gonna cut it in

half like this and then what am I gonna

do to it how do I get 3/4 I cut one of

those pieces in half that's right so I'm

gonna cut one of those pieces in half

like this so now then I have about 3/4

of the Earth's surface that's covered

with water and 1/4 that's not better

than 1/4 that's not water half of it is

in polar icecaps and high mountain

ranges we can't use it to produce that

food fiber or lumber so about half of

that again my future mathematicians when

I'm multiplying fractions I multiply the

top times the top and the bottom times

the bottom so now I have one-half of 1/4

what's 1 times 1 1 times 1 wait it's 1

what's 2 times 4 2 times 4 2 groups of 4

is 8 so now I have 1/8 of the Earth's

surface but of this 1/8 3/4 of it it's

too hot too cold too wet too dry too

steep or too shallow

can I be used to produce the food fiber

and lumber to feed clothe and shelter

all those 6.7 plus billion people on the

face of the planet what that means is

that we can't use this much

this is what we got left what I have now

is 1/4 of 1/8 anybody know what 4 times

8 is 4 times 8 it's 32 so what I have

now is 1/32 of the Earth's surface

that's how much of the Earth's surface

we use to produce that food fiber and

lumber but the whole slice isn't really

what we use the soil is just the thin

skin and that thin skin of the soil on

the face of the planet that stuff is

fragile it washes away it blows away can

you Road and so it's important for us to

take care of we build stuff on it we

lose some of this every year and so it's

very important to take care of our soil

because if we don't there won't be

enough food fiber and lumber to feed

clothe and shelter all the people on the

face of the planet so that's why it's

important to take care of your soil

because it's a scarce natural resource

and it's slowly renewable not in your

lifetime if we lose it will it be

restored and repaired