How to Build on Mars!

Making a Hypothesis

You will make bricks from a mixture of regolith and glue. You will use coarse regolith for four bricks and fine regolith for four bricks. Before you start, look at the two types of regolith and make a hypothesis (or educated guess). Which type of regolith will make the strongest bricks, and why?

Figure 1. Coarse and fine Mars simulation regolith.

Making Regolith Bricks

1. Place the liners in your baking pan.
   
   Figure 2. Mini-loaf baking pan filled with liners.
   
   
2. Pour the following ingredients in a cup, in the order listed:
   • 3 tablespoons (tbsp.) of coarse regolith
   • 2 tbsp. of glue
3. Mix with a disposable spoon until all the regolith is wet and well-mixed, as shown in Figure 3.
   
   
   
   Figure 3. Three tbsp. of regolith simulant mixed with 2 tbsp. of glue.
   
   
4. Mix in another 2 tbsp. of coarse regolith. Figure 4 shows what the result should look like.
   
   
   
   Figure 4. A total of 5 tbsp. of simulation regolith mixed with 2 tbsp. of glue.
   
   
5. If your mixture does not hold its form, add more regolith until it holds its shape and does not spread.
6. Divide the contents between 2 mini-loaves or 2 muffin cups, spooning the content in the liners.
7. Use your spoon to press the contents in the pan, flattening the top surface. An example is shown in Figure 5.
   
   
   
   Figure 5. Wet regolith bricks made from coarse regolith and glue.
   
   
8. Repeat steps 2–7, using a new cup and fine regolith instead of the coarser type.
9. If you need the pan to make more bricks, carefully take the liners with the coarse bricks out and place them on a flat surface to dry.
10. Repeat the whole process one more time so you have four bricks made from coarse regolith, and four bricks made from fine regolith. Reuse the first cup to make coarser regolith bricks and the second cup for finer regolith bricks.
11. Make notes in your lab notebook about the process. Was it easier to make one type of brick compared to the other? Do the bricks look different when wet?
12. Let the bricks dry in a warm or sunny, dry spot. If they are still in the pan, take them out after a few hours, or up to a full day, so they can dry on all sides. You might want to rotate them part-way through so the bottom dries.
13. Once dry, carefully peel off the paper liners from the bricks.
14. Make notes in your lab notebook about the appearance and feel of the two types of bricks. Did you notice if one type dried faster than the other?
15. The bricks should be totally dry before continuing. If they feel soft, wet, or sticky, let them dry longer. You can put them in the oven on the lowest setting to speed up the drying.
    
    Figure 6. Fine (left) and coarse (right) regolith bricks ready to be tested.
    
    

Testing Regolith Bricks for Strength

1. Find a place where you can drop the bricks from a set height on a hard surface, like a driveway, tiled floor, etc. A window or balcony on the second floor is ideal. Standing on a chair or table works, too. Important: Before you try this out, explain your test idea to an adult and ask permission to drop the bricks from that location and height onto the hard surface. Explain that you will cover the floor with paper to protect it.
2. Once you have permission, cover the area where the bricks will touch the hard surface with scrap paper, butcher paper, newspaper, etc. The paper is there to protect the floor. Avoid using cardboard or carpet, as that will cushion the fall. A large, thin sheet of paper or cloth is fine.
3. Make a data table in your lab notebook, similar to Table 1. It will help you to neatly record the data.

4. Bring your bricks to your test location and choose one to test first. Identify if it was made from coarse or fine regolith.
5. Measure its mass on the digital scale, preferably in grams. Write down the mass for Brick 1 in the column labeled "Initial Mass." It is fine to round all measurements to the nearest gram; that will make the calculations easier, too.
6. Hold the brick horizontally, make sure no person or animal is below the brick, and release.
   
   Figure 7. Side (left) and top-down (right) view of the test setup.
   
   
7. Look at the dropped brick. Did it break? Select the largest (heaviest) piece of brick and sweep all the other pieces to the side. If the brick did not break, the whole brick counts as the heaviest piece.
   
   
   
   Figure 8. Regolith brick after a drop.
   
   
8. Measure the mass of the heaviest piece. Write your measurement down as the mass of Brick 1 after 1 drop.
   
   
   
   Figure 9. Measure the mass of the largest remaining piece of regolith brick.
   
   
9. Repeat steps 6–8 two more times each time using the largest remaining piece to obtain the mass of Brick 1 after 2 drops and after 3 drops. Add any observations you made in the "Notes" column.
10. Keep the largest piece remaining after 3 drops. Group the largest remaining pieces according to the brick type (for instance, "Coarse"). You might want to take a picture of all the largest pieces remaining for your display board.
11. Choose a brick from the other type (coarse or fine regolith) to test next. Repeat steps 5–10 for this brick.
12. If your remaining pieces are almost identical to the initial bricks, you might have very strong bricks. In this case, we advise you to extend the test and drop the bricks several more times. You can record the mass after each drop or choose to record the mass after 2, 4, and 6 drops, or 3, 6, and 9  drops. Never skip measuring the initial mass!
13. Continue by testing a second brick from the first type, etc., alternating between types after each test until you have tested all the bricks.

Analyzing the Data

You gathered a lot of data! In this section, you will try to make sense of your observations.

1. Calculate the averages. The average is obtained by adding up the measurements (in this case, measurements for Bricks 1—4) and dividing the result by the number of measurements (in this case, 4). An example of the average of the initial mass of coarse regolith bricks together with indications of how to calculate the averages is provided in Table 2.

2. Make a graph of the data. You can make your graph on paper or use a graphing tool. The Bibliography includes a webpage that can help you create graphs. Plot the number of drops on the horizontal axis (or x-axis), and the average mass on the vertical axis (y-axis). Make two graphs, one for the Coarse Regolith Bricks and one for the Fine Regolith Bricks. Make the range of mass (the smallest and largest value displayed on the y-axis) the same on both graphs, as this will allow you to more easily compare. If you can, also plot both measurements on the same graph, as shown in Figure 10. Do not forget to give your graph a title, and to label the axes!
   
   Figure 10. Example graph using fictitious data. Note that your data will look different!
   
   
3. Looking at your data and the graph(s), what can you conclude? Does your data confirm or reject your hypothesis, or is it inconclusive?
4. What could you conclude from the qualitative observations you made? Would one type of regolith be better-suited for some applications compared to the other?
5. What would your conclusion mean for colonies on Mars?
6. If you had more time and resources, would you add anything to your research? If so, what would you add and why?