How do wheels and rollers help move things from place to place?


Targets
At the end of this unit, you should be able to answer the following questions:

1. What are simple machines, and how do they make work easier?

1.1 What advantage do I get from using a lever?

1.2 How do wheels and rollers help move things from place to place?

1.3 What role do wheel and axle systems have in moving vehicles and devices?
2. How can I build machines so they move the way I want?

2.1 How force be used to move a vehicle?

2.2 How can you build a machine or device that moves on its own?

2.3 What is needed to design a safe vehicle?

2.4 How can ideas be shared and designs be compared to build the best moving device possible?
Targets
Mail, mail, mail!  Each day, people send millions of packages and pieces of mail.  Can you imagine if all that mail had to be delivered only by people carrying it, without the help of modern sorting or delivery vehicles?  It would be impossible!  Thankfully, we have machines that make mail delivery fast and effective.  Two of the most important parts of those machines are wheels and rollers.

Wheels and rollers have been around for so long that no one knows exactly when they were invented.  Scientists think humans have been using rollers for about 10 000 years.  During all that time, wheels and rollers have been doing something very important – reducing friction and allowing objects to move easily.  Friction is the rubbing that occurs when two objects slide past one another.  Most of the time, friction is bad because it makes things harder to move, it builds up heat, and it wears away surfaces.

Career Connection

A mechanic keeps vehicles in good working order.  When something goes wrong on the vehicle it is a mechanic’s job to fix it.  Modern vehicles have many parts that include wheels and rollers, but to make sure they are safe, all those parts must be checked and repaired. Because wheels and rollers are constantly spinning, they wear out in time.  This makes the job of a mechanic very important.
Wheels and rollers are very similar, but they have one small difference.  Wheels attach to a vehicle and travel with it, allowing it to roll easily.  Rollers are used in many other devices.  Instead of moving along with the vehicle or device, rollers are usually attached in position, and other things roll over top of them.

Look closely at both pictures and you will see rollers at work.  On an exercise treadmill, a belt rolls over rollers at the front and back of the treadmill.  Usually, when a belt is placed over rollers to help us move products, heavy items, or even people, we call it a conveyor belt.  Conveyor belts are used to move items with speed and safety.  The conveyor belt used to load luggage at the airport is a very interesting machine because it has a conveyor belt on top to help workers load luggage and it has wheels on the bottom so the workers can move the whole luggage loader out of the way to get ready for the next airplane.

Agriculture Connection

Farming and the food industry have become very dependent on conveyor belts.  It would be difficult to get all the food humans need planted, harvested, and delivered to stores if it was not for conveyor belts.

Video

Watch this video: Idaho Potato Harvest

Growing and harvesting potatoes is an example of how wheels and rollers make the production and transportation of a lot of food possible.  How do you think this potato harvest would work if everything had to be done by hand instead of with the help of wheel and roller systems?