I begin this lesson by leading a discussion with students about what kinds of materials are used to make buildings. I tell students that some buildings are made of wood, stone, steel, concrete, brick or adobe and I list these list these on the board.
Next I ask students to think about which of the materials on the board come from a rock, soil or mineral? Almost all of them are directly made from rocks, soils and minerals. From the list we made, only wood is not actually a rock, soil or mineral. However, since trees need soil to grow, wood is closely related.
I tell students that when building any type of structure, engineers need to make sure they pick the right material for the job. I lead a brief discussion about those various structures and materials. For example, I might ask students to think about why they think engineers do not build airplanes out of marble? (Marble is too heavy, and the plane might not be able to lift up into the air! So engineers use aluminum, which is still strong, but much lighter.) Then I might ask why don't engineers build big skyscrapers out of wood? (Wood is not strong enough to hold up such a tall structure. We can use wood to build houses, because they are shorter.) I also ask students to think about why engineers do not build bridges out of diamonds? (Diamonds are very strong, but they are incredibly expensive, and building a bridge out of diamonds would be very difficult.)
Next, I tell students that today they are going to create the materials they will use to create buildings. In a future lesson, students will be engineers who figure out which materials are best for the buildings they are making, taking into consideration all the properties of materials that we have discussed (weight, strength, cost, appearance). However the remainder of this lesson students will spend the time prepping for the actual building.
Part I: Building
Students spend the rest of the lesson constructing four buildings as follows:
1. Carefully measure out glue and mix 4 tsp. of glue with 4 tsp. of water in the mixing bowl.
2. Next, add two full Dixie cups full of sand to the glue/water solution and stir until you have a completely damp sand mixture.
3. Then spray the inside of two bathroom cups with the non-stick spray. Then, place this mixture into the two bathroom cups so that they are nearly full. With a permanent marker, write "B" on the sides of the bathroom cups.
4. Set the cups aside so they can dry for at least four days.
5. Next, mix 1 tsp. of white glue with 6 tsp of water in a large bowl.
6. Add two full bathroom cups full of sand to the glue/water solution and stir until you have a completely damp sand mixture.
7. Spray the inside of two bathroom cups with the non-stick spray. Place this mixture into the two bathroom cups so that they are nearly full. With a permanent marker, write "C" on the sides of these bathroom cups.
8. Set the cups aside so they can dry for at least four days.
Students will create their "A" sand cups during the "testing" part of this lesson in about four days.
You can see students mixing glue and water mixture in this video.