Problem-Solving: Step 3

This week, we’re going to learn about the third step in the problem-solving process.

Step 3: Select a solution

Now that we’ve defined the problem and have some ideas, it’s time to evaluate our ideas and decide which one is the best solution to our problem. We didn’t evaluate our ideas during the previous step, so some of them may not be very good. That’s OK – it’s part of the process.

Task 1

Read the students’ discussion below and answer the following questions:

1. Which idea is selected?
2. What’s the problem with each of the other ideas?

You can download the answers here: ANSWERS.

Sarah: OK, let’s discuss each idea one by one. Let’s see, the first idea was to roll up four sheets of newspaper tightly to make legs. What do you all think of that one?

Peter: I like the idea, but I’m worried about the strength of the legs. If we roll up the newspaper very tightly, the weight of the book won’t be spread over a very big area. The table has to be at least 20 cm tall, so I think the legs will bend. Do you see what I mean?

Omar: Yes, that’s a good point. I didn’t think of that.

Sarah: OK, the second idea was to roll up the newspaper loosely – and horizontally – to make four legs. The goal was to make the legs wider.

Omar: I think that could work. If the top of each of the legs is quite wide, the weight of the book will be spread over a bigger area. That will make the table stronger, won’t it?

Jin: Yes, I think so. There’s just one thing I’m not sure about. If we roll up the newspaper too loosely, the legs may not be very strong. They’ll be wide, but maybe not strong.

Peter: Yes, I see what you mean. If we choose that idea, we shouldn’t make them too wide then.

Sarah: OK, let’s move on to the next idea. I like this one. It was to make four A-shaped legs.

Omar: Yes, I like this one, too. Triangles are usually stronger than squares and rectangles, aren’t they?

Jin: Yes, they are. The only issue I see is the height. Remember that the table has to be at least 20 cm tall. If we use one sheet of newspaper for each leg, will it be tall enough?

Sarah: Good point. I suppose it won’t be. So, the other idea – to turn the A-shaped legs upside down – won’t work either then, will it?

Peter: Hmm, I suppose it won’t. That’s a shame.

Sarah: OK, so the next one was to make a box. What do you all think?

Jin: If we make a box, it will be quite strong, I think. But I don’t think we have enough sheets of newspaper, do we?

Omar: Ah, you’re right. We’ll run out of newspaper if we try to make a box. We’d need 12 sheets.

Sarah: But I think we have enough sheets for the last idea, don’t we? That’s the one like a box but with a triangle at the top and bottom.

Peter: Yes, I think we do. We’d only need 9 sheets for that one.

Omar: Will it be strong, do you think?

Jin: I think so. The triangles will help make it strong, won’t they?

Peter: Hmm, I’m not sure about that. I think triangles only help if they’re used as part of the legs.

Sarah: That’s true, I think. Also, if we make this one, the vertical legs will need to be rolled up quite tightly. Does that mean they might bend?

Peter: Yes, good point. I think they might.

Sarah: OK, well, it sounds like the best idea we have is the table with 4 legs rolled quite loosely. Does everyone agree?

Jin: Yes, I think that’s the best idea.

Peter: I agree.

Omar: Me too.

Sarah: OK, let’s see what happens!

Discussion

Do you think their selected idea will work? Tell us in the comment below!