## Monday, June 14, 2010

### Piles of Pallets

Pallets are the unseen workers in our modern economy. They are everywhere, like tiny shipping containers! Take a look in our warehouse and tell me how many you see:

We are a net exporter of pallets. We get loads of our math material on pallets, stacked high and wrapped in plastic. Then we break those down into smaller orders for schools. Because the orders contain a number of different size boxes, and because they have to be delivered into a school environment, we can't stack things as high and they can't be as heavy. So a few high-stacked pallets come in and lots of low-stacked pallets go out. Eventually we run out.

Manuel comes to our aid. He brings us more pallets. Here's a corner of our reserve pallet inventory. We keep them piled high near the loading dock. The machine in the front is called a pallet jack. It has batteries and electric motors, allowing one person to lift and move pallets around the warehouse and onto a truck. We have some big forklifts too.

I'm writing about pallets today because of an incident while driving my old truck to work. It's about 50 years old, and slow. But even slower was an elderly Datsun pickup with a modified flat-bed load area, piled high with pallets and sagging a bit in the rear. He only caught up and passed me when I turned off for our office, but I was able to scan his load in my rear-view mirror.

He had a lot of pallets! (Here comes the math).

Q. How many pallets did the Datsun truck carry?

A. I saw 3 rows across, 3 rows front-to-back, each stacked 10 high. 3 x 3 x 10 = 90 pallets

Q. How much did all the pallets on the Datsun truck weigh?

A. The pallets on the Datsun truck were smaller than the ones we use. The truck's 3 rows x 3 rows pile was square. Knowing the average width of a vehicle is around 6 feet I estimate the size of his pallets at 2 feet x 2 feet, or 4 sq ft each.

They were made of wood - the same kind of construction as the pallets we use for Excel Math.

Our pallets are 3 feet x 4 feet, or 12 sq ft each. I put one on our scale and learned it weighs 36 lbs.
I divide to find the weight per square foot:  36 lbs  ÷ 12 sq ft = 3 lbs/ sq ft.

With this fact I can estimate the weight of the stacks on the truck.

2 ft x 2 ft = 4 sq ft x 3 lbs/sq ft = 12 lbs per pallet.  12 lbs x 90 pallets = 1080 lbs on the truck.