CHAPTER 3

Problem Solving and Systems

PROBLEM SOLVING

Humans have always been faced with problems to

solve.

They have always needed food, clothing, shelter and

healthcare.

These needs are met through technology.

People solve their problems using available

resources and knowledge.

HEADACHES

Have been a problem for a long time.

People used to drill hoes in a person’s skull!

This was supposed to let evil spirits escape. People

did not know enough about headaches to solve this

problem.

EARLY HUMANS…Solved problems of food

and shelter by using the

materials around them.

Caves were used as homes.

People gathered roots,

fruit, and seeds of plants to

eat, and made tools to hunt

animals for meat.

TODAY…

Problems are also those of human needs and

wants, but there are many more problems and they

are more complex than ever before. Some of these

problems involve society and the environment, such

as:• How can we dispose of wastes without harming the

environment?• How can we produce enough energy to meet our

increasing needs?• How can we assure a continuing supply of clean,

safe water?

GOOD DESIGN IN PROBLEM SOLVING

Solving a problem is rarely quick and easy.

We must understand exactly what is needed to solve the problem.

We must make our solution as low-cost and easy to use as

possible.

These solutions must be compared so that the best one is chosen.

Then, the best ideas are further refined and improved. Good

solutions to problems are those that work well, are

inexpensive, and cause little or no harm to the environment

and people.

EXAMPLES OF WELL DESIGNED TECHNOLOGICAL SOLUTIONS

Engineers, designers, and scientists solve a huge

number of different technological problems. These

can range from redesigning a stereo to creating new

life forms like a plant that repels insects. Here arte

some well-designed technological solutions:

THE TECHNOLOGICAL METHOD OF PROBLEM SOLVING

Problem solving is faster and easier, and results

are better, if people follow a procedure. The 7 steps

of problem solving are:• 1. Describe the problem as clearly & fully as

you can.• 2. Describe the results you want.• 3. Gather information• 4. Think of alternative solutions.• 5. Choose the best solution.• 6. Implement the solution you have chosen.• 7. Evaluate the solution and make necessary

changes.

STEP 1: DESCRIBE THE PROBLEM CLEARLY AND FULLY

To solve a problem, we must first understand it.

What has caused the problem? Here is an example of

a clearly stated problem:• People with arthritis in their fingers have a hard

time gripping small objects. They need an easy way to carry out such tasks as unlocking a door.

Once we know what a problem is, we can decide what to do about it.

RUBBER-BAND-POWERED VEHICLE

This may be a problem that might be presented in

class.

This vehicle must be able to carry a raw egg safely

over a distance of 50 feet on a smooth, level surface.

We want our vehicle to travel faster than other

competing vehicles.

In this case, the problem is to win a school

competition by constructing an egg carrying device.

To more clearly define the problem, however, we

must consider it very carefully.

RUBBER-BAND -POWERED VEHICLE CONT’D

We must recognize that winning the competition

means:• 1. We must design and construct a device powered

by rubber bands.• 2. The device must carry an egg without breaking it.• 3. The device must be faster than any other

student’s device.

STEP 2 : DESCRIBE THE RESULTS YOU WANT

We may have several goals in mind for the egg

transport problem. Perhaps we want:• To have fun• To improve our technical skills• To get a good grade• To impress our friends• Major goal to build a device that will win the

competition

DESIGN CRITERIA

Our goals should take into account any special

requirements imposed by the problem. The list of

specification must include all the requirements

of the problem. These requirements are called

design criteria.

If we were building a house, our design criteria

would include the kinds of rooms, number for

stories, and whether the house will have a basement

or an attic.

DESIGN CRITERIA FOR EGG TRANSPORT PROBLEM

1. The vehicle must carry a medium-size raw egg

without breaking it.

2. The vehicle must be painted attractively.

3. The vehicle must have an identification number.

4. The vehicle must travel faster than any other

competing vehicle.

Can you think of the other design criteria that was

mentioned?

LIMITATIONS

Problems generally have limitations.

The specifications should include these limitations.• 1. The vehicle must cost no more than two dollars.• 2. The vehicle must weigh no more than 1 pound.• 3. The vehicle must be able to fit into a 12” x 6” x 4”

container.• 4. The vehicle must be powered by no more than

four #6 rubber bands.

STEP 3: GATHER INFORMATION

This information gathering is called research.

Some companies and government agencies constantly perform

basic research into the nature of different materials and

processes. They don’t expect to produce any products immediately

from what they learn, but they save the results and hope that the

new knowledge will be useful at a later time.

Companies often do market research to determine if customers

will like a new product. Companies may ask potential buyers to fill

out a questionnaire to find out what they like or don’t like.

STEP 4 : THINK OF ALTERNATIVE SOLUTIONS

There is almost always more than one solution

to every problem.

We can suggest several ideas., each one of

which might do the job. These different ideas

for solutions are called alternatives.

One way to develop alternative solutions is to use

our past experience.

BRAINSTORMING

Another way of coming up with ideas.

During brainstorming, each person in a group can

suggest ideas.

One person writes all the ideas down; no one is

allowed to laugh at or criticize any idea, no matter

how foolish or unusual it might seem.

TRIAL AND ERROR

Another way to develop alternatives.

This is the way most people do jigsaw puzzles.

INSIGHT

A fourth way to develop alternatives.

Have you ever had an idea just pop into your head?

These sudden ideas are usually followed by the

“Aha!” response.

Insight comes from being thorough in researching

the problem, and from being creative in thinking

about the problem from many different angles.

ACCIDENT

Still, another way to come up with solutions is by

accident!

Some of the most important discoveries, like

penicillin, occur when the inventor goes as far as

possible and still doesn’t solve the problem.

A chance happening then provides the answer.

STEP 5 : CHOOSE THE BEST SOLUTION

Once you have developed your list of possible

alternatives, you need to select the best one.

Each alternative must be examined to see if it

meets the design criteria and constraints that were

defined in Step 2. Usually you can throw away the

alternatives that don’t meet the criteria or

constraints.

You may need to do further research on each

alternative.

OPTIMIZATION P. 56

Sometimes, the testing will suggest that if we

change on alternative slightly or combine two or

more alternatives, we will wind up with a better

solution.

The process of changing or combining

alternatives to improve them is called

optimization.

By optimizing the alternatives, we can get the best

possible solution to the problem.

STEP 6 : IMPLEMENT THE SOLUTION

Once we choose the best solution, we can begin to put it in place.

We are ready to try the solution under actual conditions.

Implementation means actually building or creating the

proposed solution.

Most often a prototype or model of the solution is made.

This is particularly important if the proposed solution is very large

and costly, or if many of the final products must be made, or if the

proposed solution presents risks to people or the environment.

STEP 7: EVALUATE THE SOLUTION AND MAKE NECESSARY CHANGES

We must study the solution and test is to see how

well if satisfies the requirements described in step

two.

Observing (monitoring) the results of the test may

suggest how we can improve the design or

construction of the solution.

The feeedback we get allows us to compare our

actual results with the desired results.

SOLVING REAL-WORLD PROBLEMS

Social and Environmental Concerns

Politics

Risk/Benefit Trade-Offs

Need for Continued Monitoring

Values

SYSTEMS

A system is a means of getting a desired result.

A technological system does this through technology.

For example, an automobile is a technological system for

traveling from one place to another.

A radio lets us listen to music or news.

A computer lets us do calculations quickly.

A system can be huge, such as a space shuttle. Or it can be

small, like a pocket calculator.

TECHNOLOGICAL SYSTEMS ARE ALL ALIKE IN ONE WAY…

Each has:• Inputs• A process• Outputs

THE BASIC SYSTEM MODEL

All systems include inputs, a process, and outputs.

Feedback is added to provide a better way of

controlling the system.

The basic system model can be used to

describe any technological system.

A system diagram can be drawn to show how these

parts work together in a system…..

INPUTS

The input is the command we give a system.

It is also the desired result.

When we turn on a t.v., we are giving it a

command. That command is: “Give us picture and

sound.”

THE PROCESS

The process is the action part of a system. It

combines the resources and produces results.

In an automobile, the process involves both the car

and the driver. The seven technological resources

are used in the process. Energy is stored in the

gasoline. The machine is the car. People (the driver),

information, time, materials, and capital work

together to make the car go 30 miles an hour.

OUTPUTS

The output is what is produced. It’s the actual

result.

We hope that the output matches the command

input.

That is, we hope that the car will go 30 miles an

hour when we step on the gas.

Most systems have more than one output.

FEEDBACK

How does the driver know when the car is going 30 miles

an hour?

The driver checks the speedometer. The speedometer

gives the driver feedback.

Feedback is information about the output that can be

used to change it.

When the car’s speed reaches 30 miles an hour, the

driver lets up on the gas.

MONITOR

The speedometer is a monitor.

A monitor gives feedback about output. It lets

us compare the actual result to the result we

want.

We can control the system, if needed, to get the

output we want.

Systems with feedback are sometimes called

control systems or feedback control systems.

CONTROL SYSTEM

A control system is being used to help you learn.

Your teacher uses homework and tests as monitors

to see how well you are learning.

Your teacher grades and returns assignments

both of you use this feedback to find out where you

are doing well and where you need more work or

perhaps some help.

LOOP SYSTEMS

Systems that have feedback are called closed-loop

systems. Feedback “closes” the loop from input to output.

Some systems don’t use feedback – these are called open-

loop systems. A person who wears a blindfold while trying to

draw a picture of a dog is an example of an open-loop system.

Without feedback, the person cannot compare the output to the

input. When the blindfold is removed, the person can draw the

picture more accurately. Now we have a closed-loop system.

MULTIPLE OUTPUTS

A system may produce several outputs. They

can be 4 types: desirable, undesirable, expected,

or unexpected.

SUBSYSTEMS

Systems are often made up of many smaller

systems called subsystems.

When you are trying to understand a large system,

you might find it helpful to break it into subsystems.

You can study each of them separately.

Suppose you want to look at a transportation

system that carries goods by truck from L.A. to New

York City.

You could break down the large system into smaller

ones.

Some of the subsystems would be the vehicle

system, the management system, and the

communication system.

Each of these could be broken down further into

more subsystems. You would want to create a

subsystem tree.

See figure on page 70.

IN YOUR NOTEBOOK, ANSWER THE FOLLOWING ITEMS

1. What are the 7 problem-solving steps listed in

this PowerPoint?

2. Give an example of how a person’s values might

affect his or her decision about the kind of car to

buy.

3. Name some subsystems that make up a large

railroad system.