For TeachersEngineering Design in Oregon Science ClassroomsPage 1 of 2
Read Aloud–Think Aloud for Bricks for Pigs
This document contains the text of the Bricks for PigsReading handout, and includes with reading activity prompts for the teacher. Lesson vocabulary is bolded when it is defined.
Do you know the story of the three little pigs?
[Give students a chance to share their knowledge of the story.]
Do you remember how it ends?
[Let a student describe how the story ends.]
That’s right. After the first pig’s straw house and the second pig’s stick house got blown away by the big bad wolf, they all ended up living in the third pig’s brick house.
The pigs have a problem, though. They can’t seem toget along. In fact, they fight all the time over things likewhose turn it is to do the dishes, who tracked mud intothe house again, and who drank the last of the milk.
[Let students share their ideas about what the pigs can do about their problem.]
The pigs decide to build two more houses, so they take a trip to the Piggly-Wiggle General Store to buy bricks.
If bricks cost 20 cents each and it takes 500 bricks to build a house, how much will it cost to build a house out of brick?
[Answer: $100]
Mother Goose gave the pigs $50 for their birthdays. If they pool their money, how much do they have to spend on each house?
[Answer: $75 for each house]
Do the pigs have enough money to make two more houses out of bricks?
[No—they are short by $50]
What can they do?
[Let students share their ideas about what the pigs can do about their problem.]
While the first and second pig argued over how to make more money, the third pig had the idea to act like engineers.
“I know! Let’s use the Engineering Design Process!”
“How do we do that?” asked the first pig.
[Let students share their ideas about bricks and how they are made.]
“How do we do that?” asked the first pig.
“Engineers make their own solutions to problems. Let’s make ourown bricks! We can mix sediments like sand, gravel or stones with asticky binder like glue.”
“Yes, but how do we know how much of each item to use?”
[Let students share their ideas about how to figure this out.]
“Its easy. We’ll figure it out by using engineering design process.”
“That doesn’t sound easy.” Remarked the first pig.
“But it is! If you follow the steps. I’ll break the process down foryou. First you make a problem statement—the thing you need to fix.
[Ask students what the pigs’ problem statement might be.]
“We need bricks to make two more houses, but can’t afford to buythem.” Cried out the second pig. “Is that our problem statement?”
“Exactly. Next you determine your criteria and constraints. Criteriaare the goals you want to meet. For example, the bricks we makeneed to be strong enough to withstand weathering and erosion—things like the wind and the rain, and the big bad wolf!”
“My criteria is style. I want a house that’s really stylish!” Said thefirst pig.
“That’s fine,” said the third pig, “as long as it still meets our othercriteria. Remember how much you cried when the wolf blew yourhouse down?”
“Why do you have to keep bringing that up?”
“Anyway,” said the third pig. “Next we have to think about ourconstraints—the limitations that make it harder for us to solve theproblem.”
“Like cost?” said the first pig.
“Yes. Our biggest constraint is cost. Let’s see... if we have 75dollars to spend on each house and it takes 1,000 bricks to builda house, how much money do we have per brick?”
[Answer: 13.3 cents per brick]
“Okay, well the third step of the engineering design process is to brainstorm solutions. Given our budget, I think we should trymaking bricks out of sand and gravel.”
“Oh, what about these colored pebbles?” Asked the second pig.“They’re cheap and I can use them to make striped bricks. Thatwould be so cool.”
“That’s a good idea,” said the third pig, “things like color andhardness are called properties. You want to pick materials withproperties that meet your criteria—the stripes sure would be stylish!”
“The first pig remembered something. He said, “We also need some sort of binder that will hold the different piecesof sediment—the rocks, sand, and pebbles—together.”
“Oh, I know,” cried the second pig. “We can hold everythingtogether with clay. That stuff gets really hard if you let dryout. That’s a good property, right?”
“Good idea!” Said the first pig.
“It’s a good idea, but the only way we’ll know if it’s a goodproperty is to make a prototype, our first try at making thesolution,” said the third pig.
“Then what?” asked the first pig.
“After we make the prototype, we test it. If it’s good, wehave our solution, and we can start making all the bricks weneed. But if it doesn’t meet our criteria, we’ll have to keeptrying different materials and new prototypes, until we finda brick that works”
“Then let’s get to it!” cheered the second pig.