With their wrecking ball tests complete, first graders are reflecting upon the results of their tests. Materials engineers need to analyze the results from their materials tests.

What angle did their wall last to?  Did the walls crack?  Did they use enough of their mortar?  Where were the rocks once their walls fell?  What mixture did they use?  

But ultimately, what could they do to improve their walls? And why?

As they walk through the Engineering Design Process, first graders are developing improved solutions to their walls!  See their improvement ideas below! Awesome thinking 1st grade!

With their mortar mixtures all dried, first graders began testing the strength of their walls using a wrecking ball.  A wrecking ball is brought up to different angles, and with each increasing angle comes more force.  Will their mortar mixtures last? 

First graders are hoping that their mortar mixtures withstand the force of the wrecking ball up to Angle 4, which is the highest angle.  

With their mortar mixtures in hand and their rocks ready to be staggered, first graders built their walls today!  As materials engineers, they made a new mortar because their original mortars failed all of the tests.  First graders suggested that a new mixture will help keep the rocks in place.  

We'll have to wait for the mortar to dry in order to test our walls' strength!  Check back next week for the results!  We wonder which mortar mixture will stand up to the greatest angle of the wrecking ball!

Mortar mixture recipes...check!
Staggered rocks are better than stacked rocks...check!
Knowing where to put rocks...check!

First graders investigated the rocks they'll be using to build their walls, thinking about each rock's unique properties.  Some rocks were pointy, making them good to sneak between jagged areas.  Other rocks were small and couldn't support a lot of weight at the base of the bottom, leaving a first grader to acknowledge their future use at the top of a wall.  Great thinking first graders!

Since first graders have analyzed the results of their mortar tests, they know they have to design a new mortar mixture!  Each pair of first graders has created a "recipe" for the earth materials they want to use in their mixtures.  They could choose different combinations of sand, clay, and soil.  

The next important part comes at looking at the structure of their walls.  Before students actually use the mortar mixture and rocks, it is important to know how to stack the rocks they'll use in their wallsl.  In lieu of using rocks for their initial tests, first graders used Legos to build walls with blocks that were both stacked and staggered.  Using a wrecking ball to test the strength of their walls, students quickly discovered that staggered walls disperse the force and stay standing a lot longer than their stacked wall counterparts!

First graders spent time today completing the three tests they designed for each of the three mortars--sand, soil, and clay.  Testing materials is an important part of an engineer's work, and today, the results of our tests surprised us.  Not one mortar passed all three tests.  This means none of them will be a strong and sticky enough mortar for our walls.  What should we do now materials engineers?  

Now that first graders have made observations for both dry and wet mortars, they still have questions about what happens to it after it dries.  Will the clay still be the stickiest mortar once the moisture is gone?  There's only one way to find out!  Test it (and the others)! 

Each class came up with their own tests to see if the mortars stay strong and sticky once they dry.  Ms. Hall's class came up with the wall test, the sandwich test, and the earthquake test.  Ms. McDonald's class also had the sandwich and earthquake tests, and named their third test the up-and-down test.  We will wait until the mortars dry to test each of them.  

None of the earth materials were sticky enough when they were dry.  So first graders wanted to add water to them and make a mixture.  Would making a mixture make them stickier?

Adding water to each of the earth materials, first graders observed how the properties changed.  Every earth material got darker, and they also all got stickier, too!  There was a range of colors and stickiness, making students think about how some mixtures would make a better mortar than others.

First graders' next steps will be designing tests to find out which earth material is truly the stickiest and strongest once it dries!

As materials engineers, it is important to know and understand the types of materials available for creating a technology.  Remember that as materials engineers, first graders will be making their own mortars to build a wall out of rocks.  Their walls will keep a hungry bunny out of a school garden!

It is more affordable to make our own mortars than buying them, so we're looking to use earth materials.  We're first exploring the earth materials when they are dry, identifying the distinguishing properties between clay, sand, and soil.  Are they smooth?  Soft?  Sticky?  What size are their particles?  Are the particles the same size or different sizes?  

Materials engineers are constantly exploring materials.  They think about how they can use materials differently and for different purposes.  First graders are working on expanding their "imagination" skills to see how different materials can be used for the same purpose.  Then, they are thinking about how some materials are better for one purpose more so than another!