Engineering Design and Applied Technology

Lesson: Finding Problems and Understanding Needs

In science and engineering, people look around carefully to find things that are hard, unsafe, or not working well. Then they think about what people need to make life better.

This is called problem identification and needs assessment. That means we first notice a problem, and then we figure out what is needed to help solve it.

Engineers are people who design and build helpful things. Before they make something, they ask: What is the problem? and What do people need?

Introduction: Look, Notice, and Think

Sometimes a problem is easy to see. A floor is wet and someone could slip. A backpack is too heavy to carry. A classroom has no place to put crayons.

Sometimes a need is something people are missing. Maybe a child needs a way to reach the sink. Maybe a pet needs clean water. Maybe people need a safer way to cross a street.

When we look closely at the world around us, we can find problems that need solutions.

Main Teaching Point 1: What is a problem?

A problem is something that is not working well, is hard to do, or could hurt someone.

• Something is too hard to use.
• Something is unsafe.
• Something is missing.
• Something takes too much time or makes a big mess.

We can find problems by using our eyes and ears and by thinking carefully about what we see.

We can ask:

• What is not working?
• What is hard to do?
• What could be unsafe?
• What is missing?

Main Teaching Point 2: What is a need?

A need is something a person must have to be safe, healthy, or able to do a job.

Needs are different from wants. A need is important. A want is something nice to have.

• Need: a lid for a paint cup so paint does not spill
• Want: a paint cup with stars on it

When we think about needs, we ask:

• Who needs help?
• What do they need?
• Why do they need it?

Main Teaching Point 3: Observe the environment

Observe means to look very carefully. We can observe the classroom, playground, home, or school.

When we observe, we notice details.

• Is something broken?
• Is something in the way?
• Is something hard to reach?
• Is something dangerous?

Good observers do not guess too fast. They look first. They think next.

For example, if water keeps spilling near the sink, the problem is not just "water." The real problem might be that the paper towels are too far away, or the sink splashes too much.

Main Teaching Point 4: Identify who the problem affects

After we find a problem, we think about who it affects.

• Does it affect one child?
• Does it affect the whole class?
• Does it affect families or pets?

This helps us understand the need better. If many people have the same problem, it may be important to solve.

Main Teaching Point 5: Say the problem clearly

It helps to say the problem in a clear sentence.

We can use this frame:

The problem is...

• The problem is our books fall off the shelf.
• The problem is students cannot reach the soap.
• The problem is toys are left on the floor and people can trip.

Then we can say the need:

People need...

• People need a way to keep books standing up.
• People need a safe way to reach the soap.
• People need a place to put toys away.

Main Teaching Point 6: Some problems are safety problems

Some problems can cause accidents. These are safety hazards. A safety hazard is something that could hurt someone.

• A wet floor
• Sharp edges
• Toys on stairs
• A loose chair leg

If we notice a safety problem, we should tell a grown-up right away.

Main Teaching Point 7: Some problems are about making things work better

Not all problems are dangerous. Some things are just slow, messy, or hard to use.

• Pencils roll off desks.
• Markers dry out because caps are lost.
• Lunch boxes get mixed up.

These are problems too. Engineers can design things to help.

Worked Example 1: A simple classroom problem

Let us look at the art table. Crayons keep falling on the floor.

Step 1: What do we observe?

• Crayons are on the table.
• The table gets bumped.
• Crayons roll off.

Step 2: What is the problem?

The problem is crayons fall on the floor.

Step 3: Who does it affect?

It affects the children using crayons and the teacher who has to pick them up.

Step 4: What is the need?

People need a way to keep crayons in one place.

Step 5: Could we design something?

Yes. We could design a crayon holder.

Worked Example 2: A safety problem

Now let us look near the sink. Water is on the floor.

Step 1: What do we observe?

• The floor is wet.
• Children walk there.
• Someone could slip.

Step 2: What is the problem?

The problem is the wet floor is not safe.

Step 3: Who does it affect?

It affects everyone who walks by the sink.

Step 4: What is the need?

People need a safer way to keep the floor dry.

Step 5: What should we do first?

Tell a grown-up. Safety problems need quick help.

Worked Example 3: A harder example with a missing tool

In the reading corner, books keep falling over because the shelf is wide and the books are few.

Step 1: What do we observe?

• The books do not stand up well.
• They slide and tip over.
• Students have trouble finding books.

Step 2: What is the problem?

The problem is the books fall over and are hard to use.

Step 3: Who does it affect?

It affects students who want to choose books.

Step 4: What is the need?

Students need a way to keep books standing up.

Step 5: What might be designed?

A book divider or a small book holder could help.

Worked Example 4: Looking carefully before deciding

At recess, children are waiting a long time for turns at the ball box.

At first, someone might say, "We need more balls." But let us observe carefully.

Step 1: What do we observe?

• The line is long.
• The box is hard to open.
• Only one child can reach inside at a time.

Step 2: What is the problem?

The problem may be that the box is hard to use, not only that there are too few balls.

Step 3: What is the need?

Children need an easier way to get the balls.

Step 4: Why is careful observing important?

Because if we do not look closely, we may try to solve the wrong problem.

How to Identify a Problem and a Need

1. Look around carefully.
2. Notice what is hard, unsafe, messy, or missing.
3. Say the problem in a clear sentence.
4. Think about who is affected.
5. Say what people need.
6. Then think about a design that could help.

Helpful sentence starters

• I notice...
• The problem is...
• This affects...
• People need...
• A design could help by...

Quick Practice

Read each one and think: What is the problem? What is the need?

• Lunch bags all look the same, so children grab the wrong one.
• Rain boots drip water by the door.
• Blocks are mixed together, and it takes a long time to find the right one.

Possible answers:

• The problem is lunch bags get mixed up. People need a way to tell whose lunch bag is whose.
• The problem is water drips by the door. People need a way to keep the floor dry.
• The problem is blocks are hard to find. People need a way to sort and store the blocks.

Remember

Good solutions start with good problem finding.

If we do not know the real problem, we cannot make the best design.

That is why engineers observe carefully, identify the problem clearly, and understand what people need.

Brief Summary

Problem identification means finding something that is hard, unsafe, missing, or not working well.

Needs assessment means figuring out what people need to help solve that problem.

We observe carefully, say the problem clearly, think about who is affected, and then decide what kind of design could help.

Defining Criteria and Constraints

When people make or build something to solve a problem, they need a plan.

Before they start, they ask two important questions:

• What does it need to do?
• What limits do we have?

The answers help us learn about criteria and constraints.

What are criteria?

Criteria are the things a design should do. They are the goals.

Criteria help us know if a design is working well.

For example, if we make a paper bridge, one criterion might be that it holds 3 pennies. If it holds 3 pennies, it meets the goal.

That is something we can check and measure.

What are constraints?

Constraints are the limits. They tell us what we cannot go past.

Constraints can be about:

• Time — maybe we only have 10 minutes.
• Materials — maybe we can only use paper, tape, and straws.
• Money — maybe we can only spend a little.
• Size — maybe it has to fit in a small space.
• Gravity — things can fall down, so the design must stay up.

Constraints are not the goals. They are the rules and limits we must follow.

Criteria and constraints work together

A good design tries to meet the criteria while staying inside the constraints.

Let’s think about making a tower.

• Criterion: The tower should stand up by itself.
• Constraint: You may only use 10 blocks.

If the tower stands up but uses 14 blocks, it did not follow the constraint.

If the tower uses 10 blocks but falls down, it did not meet the criterion.

To solve the problem, we need to do both.

How do we find criteria?

Ask, “What does this need to do?”

You can also ask:

• Does it need to be strong?
• Does it need to move?
• Does it need to hold something?
• Does it need to stay dry?
• Does it need to go fast or slow?

Good criteria are clear. We should be able to test them.

For example, “The boat should float for 1 minute” is clearer than “The boat should be good.”

How do we find constraints?

Ask, “What limits do we have?”

You can also ask:

• How much time do we have?
• What tools can we use?
• What materials can we use?
• How big can it be?
• How much money can we spend?

Constraints help us make smart choices.

Worked Example 1: A hat for the rain

Problem: Make a hat to help keep rain off a toy.

First, ask what the hat needs to do.

• Criterion: The hat should cover the toy’s head.
• Criterion: The hat should stay on for 1 minute.

Now ask what limits we have.

• Constraint: You may only use paper and tape.
• Constraint: You have 15 minutes to build.

If the hat covers the head and stays on, it meets the criteria.

If it uses cloth or takes too long, it breaks the constraints.

Worked Example 2: A paper bridge

Problem: Make a bridge for a toy car.

Let’s choose the criteria.

• Criterion: The bridge should let the toy car cross.
• Criterion: The bridge should hold 2 toy cars.

Now the constraints.

• Constraint: Use only 1 sheet of paper and 2 pieces of tape.
• Constraint: The bridge must go across a space 10 cubes wide.

We can measure if it works. If 2 toy cars can stay on the bridge, then it meets one criterion.

If the bridge is too short for the 10-cube space, then it does not work, even if it is strong.

Worked Example 3: A small boat

Problem: Make a boat that floats.

Criteria are the goals.

• Criterion: The boat should float in water.
• Criterion: The boat should hold 3 pennies.

Constraints are the limits.

• Constraint: Use only foil.
• Constraint: You get 1 square of foil.

We can test the boat by adding pennies, one at a time.

We might count like this: \(1\), \(2\), \(3\).

If the boat floats with 3 pennies, it meets the criteria.

If we use extra foil, we did not follow the constraints.

Worked Example 4: Build a tall tower

Problem: Build the tallest tower you can.

This problem is a little trickier because we need to think carefully.

What is the goal?

• Criterion: The tower should stand up by itself.
• Criterion: The tower should be taller than 8 cubes.

What are the limits?

• Constraint: Use only 12 straws.
• Constraint: Use only 4 small pieces of tape.
• Constraint: Build in 20 minutes.

If the tower is very tall but falls over, it does not meet the criterion.

If it stands and is tall enough but uses too much tape, it breaks the constraint.

The best design does the job and follows the rules.

How to tell the difference

Sometimes criteria and constraints can feel similar. Here is a simple way to remember:

• Criteria = goals
• Constraints = limits

You can think:

• “Need to do” means criterion.
• “Need to stay within” means constraint.

Let’s sort some ideas

Suppose we are making a kite.

• “It should fly in the wind.” → Criterion
• “Use only paper, string, and tape.” → Constraint
• “It should stay together.” → Criterion
• “Finish in 15 minutes.” → Constraint

Why this matters

Engineers solve problems for people. They build things like bridges, toys, tools, and shelters.

They must know the goals and the limits before they begin.

That helps them make better choices and build designs that work.

Try these steps when you design

1. Read or listen to the problem.
2. Ask, What does it need to do?
3. Write the criteria.
4. Ask, What limits do we have?
5. Write the constraints.
6. Build and test.
7. See if your design meets the criteria and follows the constraints.

Quick check

Problem: Make a chair for a toy bear.

• It should hold the toy bear. → Criterion
• It should not tip over. → Criterion
• Use only 6 craft sticks. → Constraint
• Use only glue and paper. → Constraint

Summary

Criteria are what a design must do. They are the goals we can test.

Constraints are the limits we must follow, like time, money, size, gravity, and materials.

When we design something, we want it to meet the criteria and stay within the constraints.

Iterative Design and Optimization means we make something, test it, learn from it, and make it better.

Sometimes our first idea does not work the way we want. That is okay. In science and engineering, that helps us learn. A problem can give us clues.

When something does not work yet, we can ask, What happened? Then we can change one part and try again. This is called improving or optimizing.

Engineers often follow a simple cycle:

1. Ask: What is the problem?
2. Imagine: What ideas could help?
3. Build: Make a model or try an idea.
4. Test: See what happens.
5. Improve: Change it to make it better.

This cycle can happen again and again. That is why it is called iterative. Iterative means repeating the steps.

Let us think about a tower made of blocks. The problem is: Can we build a tall tower that stays standing?

You build a tower, but it falls down. Is that the end? No. Now you learned something. Maybe the bottom was too small. Maybe the top was too heavy.

Next, you can try a new idea:

• Make the bottom wider.
• Use bigger blocks on the bottom.
• Use fewer blocks on top.

Then you test again. If it stands longer, your new design is better.

Failure helps us learn. Failure means something did not work yet. It does not mean we should quit. It gives us information.

We can say:

• I tested it.
• I saw what happened.
• I changed my design.
• I tested again.

That is how engineers solve problems.

When we test, it helps to change one thing at a time. Then we can tell what helped.

For example, if a paper airplane does not fly far, we might change only the wings first. Then we test. After that, we might change only the nose. Testing one change at a time helps us notice what works best.

We can also compare results. Maybe one test goes 2 steps, and the next test goes 4 steps. Since 4 is more than 2, the second design went farther.

We can write it like this:

$$4 > 2$$

That means 4 is greater than 2.

Main ideas to remember:

• Your first try does not have to be perfect.
• Testing helps you learn.
• If something fails, you can still use that information.
• Redesign means changing your idea.
• Optimize means making it work even better.

Let us look at some examples.

Worked Example 1: A block bridge

Problem: Build a bridge that can hold 3 toy cars.

First design: You make a bridge, but when you put on the cars, it bends too much.

What did you learn? The bridge is not strong enough.

What can you change? You can add another block under the middle.

Test again: Now the bridge holds all 3 cars.

So what happened? The first test showed the problem. The second design was better because you improved it.

We can count the cars:

$$1 + 1 + 1 = 3$$

The bridge needed to hold 3 cars, and now it does.

Worked Example 2: A paper airplane

Problem: Make a paper airplane fly farther.

First test: Your airplane flies 2 steps.

Second design: You fold the wings a little flatter.

Second test: Now it flies 5 steps.

What did you learn? The flatter wings helped the airplane fly farther.

We can compare:

$$5 > 2$$

The new design is better because 5 steps is farther than 2 steps.

Worked Example 3: A cup tower

Problem: Build the tallest tower from cups.

First design: The tower is 4 cups tall, but it falls.

Second design: You make the bottom wider.

Second test: The tower is still 4 cups tall, and now it stays up.

Third design: You keep the wide bottom and carefully add 1 more cup.

Third test: Now it is 5 cups tall and stays up.

We can compare the heights:

$$5 > 4$$

You improved the design step by step.

Worked Example 4: Keeping an ice cube cold

Problem: Which wrap helps an ice cube stay cold longer?

First test: An ice cube with no wrap melts fast.

Second test: You wrap an ice cube in cloth. It lasts longer.

What did you learn? The cloth helped keep the ice cube cold longer.

Now you can improve again. You might try thicker cloth next time.

This is iterative design because you test, learn, and change your idea.

How to be a good young engineer:

• Look closely at what happens.
• Talk about what worked and what did not work.
• Draw your idea before and after changes.
• Keep trying.
• Use what you learned from each test.

Here are some helpful sentence starters:

• My problem is...
• My first idea is...
• When I tested it, I saw...
• Next I will change...
• My new design is better because...

Remember, engineers do not always get it right on the first try. They learn from each test. They use mistakes to help make things better.

Brief Summary

Iterative design means trying again and again to improve something. We build, test, learn, and redesign. If something fails, we can use that result to help make a better design next time.

Friction Reduction: Wheels, Axles, and Ramps

We use simple tools to make work easier. Three very helpful tools are wheels, axles, and ramps.

These tools help us move things. They can help us push, pull, or lift with less effort.

One reason they help is called friction. Friction is a force that makes things rub and slow down when they touch.

Think about sliding a box across the floor. The box rubs on the floor. That rubbing makes it harder to move.

Now think about a toy car. Its wheels turn and roll. Rolling is easier than sliding, so the car can move more easily.

What is friction?

Friction happens when two things touch and push against each other. Friction can be helpful or not helpful.

• Friction helps your shoes grip the ground.
• Friction helps you hold a pencil.
• Too much friction can make pushing something feel hard.

When we want to move something, we often want less friction.

Wheels and axles

A wheel is the round part that turns. An axle is the rod in the middle that helps the wheel spin.

Together, a wheel and axle help objects roll. Rolling usually has less friction than sliding.

That is why bikes, wagons, cars, and shopping carts have wheels and axles.

If you drag a heavy toy box, it may feel hard. If you put it on a wagon with wheels, it is easier to move.

Why rolling helps

When something slides, a lot of its bottom touches the ground and rubs. When something rolls, the wheel turns, so it does not scrape along in the same way.

Less rubbing means less friction. Less friction means less effort to move the object.

Ramps

A ramp is a slanted surface. Another name for a ramp is an inclined plane.

A ramp helps lift or lower things. Instead of lifting something straight up, you can move it up the ramp.

Using a ramp means you move the object a longer way, but it can feel easier because you do not have to lift it straight up all at once.

So a ramp trades more distance for less lifting effort.

You may walk farther on a ramp than straight up stairs, but the climb can feel easier.

Wheels on ramps

Wheels and ramps often work well together. A cart with wheels can roll up a ramp more easily than a box can be lifted straight up.

This is a smart way engineers solve problems. Engineers think about how to make moving things easier, safer, and faster.

Look for these ideas

• Sliding usually has more friction.
• Rolling usually has less friction.
• Wheels and axles help things roll.
• Ramps help move things up or down with less lifting.
• A ramp means going a longer way to make the job easier.

Worked Example 1: Slide or roll?

Lina wants to move a heavy box across the room. She can:

• slide the box on the floor
• put the box on a small cart with wheels

Question: Which way will likely be easier?

Answer: The cart with wheels will likely be easier.

Why? Wheels roll, and rolling has less friction than sliding. Less friction means Lina does not have to push as hard.

Worked Example 2: Lift or use a ramp?

Ben needs to move a box into a truck. He can:

• lift the box straight up
• push the box up a ramp

Question: Which choice can make the job easier?

Answer: Pushing the box up a ramp can make the job easier.

Why? The ramp is a slanted path. Ben moves the box a longer distance, but he does not have to lift it straight up all at once.

Worked Example 3: Which has less friction?

Maya tests two toys:

1. A block she slides across the table
2. A toy car she rolls across the table

Question: Which toy has less friction while moving?

Answer: The toy car has less friction while moving.

Why? The car uses wheels and axles. The wheels turn, so the car rolls instead of slides. Rolling reduces friction.

Worked Example 4: Picking the best tool

A worker wants to move many heavy books to a higher shelf area. Which tool is the best helper?

• a wagon with wheels only
• a ramp only
• a cart with wheels and a ramp

Answer: A cart with wheels and a ramp.

Why? The wheels help the cart roll with less friction. The ramp helps move the books higher with less lifting. Using both tools together makes the job easier.

Try thinking about real life

• Suitcases have wheels so we can roll them.
• Wheelchairs use wheels to move more easily.
• Moving trucks use ramps to load heavy things.
• Strollers use wheels and axles to carry babies.

Engineering connection

Engineers design things to help people solve problems. If something is too hard to carry, engineers may add wheels. If something is hard to lift, engineers may add a ramp.

They ask, “How can we make this easier to move?” Wheels, axles, and ramps are smart answers.

Quick review

• Friction is rubbing that can slow things down.
• Rolling usually makes less friction than sliding.
• A wheel turns around an axle.
• A ramp is a slanted path that helps lift with less effort.
• Ramps make the path longer, but the lift easier.

Summary

Wheels and axles help objects roll, and rolling reduces friction. This makes heavy things easier to move.

Ramps help us move things up or down without lifting straight up. They make the trip longer, but they make the work easier.

When we use wheels, axles, and ramps, we use science and design to solve everyday problems.