Aisha is a spirited, energetic girl...  

..who lives in Boston, Massachusetts.  

Aisha and her cousin Tanya can’t wait to visit the potato chip factory where Aisha’s brother Malcolm, an industrial engineering student, is working on a summer internship. Malcolm agrees to take the girls to the factory—on the condition they complete their summer assignment for school. Aisha and Tanya become intrigued by the drawings Malcolm is working on. The drawings show simple machines used in the potato chip factory. Aisha and Tanya decide to focus their summer project on simple machines, too.  

As an example of a simple machine, Malcolm has the girls try to push his heavy pile of textbooks across the table. They have trouble, so he then lines up a bunch of pencils on the table and puts the books on top of them. “Try pushing them now,” Malcolm says. This time, it is much easier to push the books because the pencils act like wheels and make the work easier by reducing friction. Tanya remarks that she studied things that make work easier, like wheels, in school last year and that they are called simple machines. “We use lots of simple machines at the factory,” Malcolm explains. “All the big machines are made up of smaller parts, called subsystems. A lot of the time those subsystems are made up of simple machines.”

This gives Aisha an idea – “That’s what we can do our project on This gives Aisha an idea – “That’s what we can do our project on!” she exclaims. The girls decide to do their project on how simple machines make work at the factory easier. Malcolm explains that simple machines are everywhere, not just at the factory, and suggests they go on a simple machine scavenger hunt. Before they even leave the house, Aisha finds one—a lever on the doorknob.

The three walk to a theater where Malcolm’s friend Sean works The three walk to a theater where Malcolm’s friend Sean works. Sean helps set up the stage for performances. Aisha says she would just dance all the time if she worked there. When they get to the stage, Sean shows the girls how they move the scenery during a performance.

When he pushes a button on the wall, an outdoor scene floats down from the ceiling. Sean points to the machinery hanging from the ceiling and explains that the scenery is moved by using a bunch of pulleys – wheels with ropes that run around them. They are used at the theater to change the direction of forces. When Sean pulls down on one end of the rope, the pulley causes the other end of the rope to pull the scenery up.

Malcolm tells the girls that they are natural engineers, to which they reply, “Engineers who dance!” The two then whirl and twirl around the stage, imagining themselves in fancy costumes with a crowd in the audience.

They then go through the Boston Common toward the State House and see a monument dedicated to Colonel Robert Shaw and the 54th Regiment of the Union Army, which was the first all-black volunteer regiment to fight in the Civil War. Tanya says this is one of her favorite neighborhoods because the houses are so old that she can imagine horse-drawn carriages on the streets. Aisha says cars and carriages aren’t all that different because they both work with wheels and axles. “That’s a great observation,” says Malcolm. “Once you start spotting simple machines, you can start to see how complicated systems, like cars, are just arrangements and combinations of simple machines.”

At the Abiel Smith School and Museum of Afro-American History, Tanya tells Malcolm, “Aisha’s not the only one who can spot simple machines! Check out that flagpole on the schoolhouse. There’s a pulley on it!”

When they get to Aisha’s dad’s restaurant, Aisha and Tanya tell him about the simple machines they have spotted so far. Malcolm mentions that their father’s knife is a good example of another simple machine –the wedge. A wedge is used to push things apart – the thin edge of the knife concentrates the force put on it to make it easier to push the food apart. When Malcolm refers to this as a “technology,” Aisha is confused because it isn’t electric. “Technology is more than just electronic gadgets,” Malcolm explains. “Technology is any thing or process that people design to solve a problem.”

They find more simple machines like wedges, wheels, and axels in kitchen tools like cookie cutters, a juicer, and a hand eggbeater.

After lunch, Malcolm takes the girls to the Museum of Science to complete their simple machine scavenger hunt. They find a sculpture that uses lots of simple machines—a Rube Goldberg machine…  

…and play on a giant lever (or see-saw) in the Science in the Park exhibit. Peeking in at the incubator with baby chicks, Aisha realizes that the chicks have a built-in simple machine—their beaks act as wedges to help them break out of their shells.  

The next day, Malcolm takes the girls to the potato chip factory…

…where they see all of the simple machines in the factory subsystems – the wheels and axels in the conveyer belt that bounces the dirt off the potatoes, the wedge in the slicer that cuts the potatoes, and the sliced potatoes sliding down the inclined plane.

Malcolm tells the girls that once the chips are packaged, they are shipped from the factory to places all over the USA.  

Inspired by their visit to the factory, Aisha and Tanya use what they learned about the factory subsystems to design a model of a factory subsystem that they will show to their class.  

Malcolm introduces the girls to the Engineering Design Process and explains that the steps of the process can be very helpful to engineers as they try to design something. With Malcolm’s help, the girls “Ask,” “Imagine,” “Plan,” “Create,” and “Improve” their factory subsystem design.  

After a few improvements, Aisha and Tanya find success After a few improvements, Aisha and Tanya find success! Their factory subsystem design makes the work of lifting a heavy load of potatoes a lot easier.