Action|Sophisticated materials and equipment:

3 trays

All the same size and depth.

Watering can with holes in the lid.

Incliners

Notebooks or other object to give it the inclination.

Suitable for trays

Homemade cylinder: graduated glass with the width of a finger

Colored pencils

Field notebook

Cardboard

Process:

1) 2) 5)

Before starting, Violeta invited her neighbor and classmate Clara to do the experiment together, since they would need a pair of hands, a pair of eyes and a brain to carry it out.

Between the two of them they prepared the place for the experiment and gathered all the necessary materials. Using a glass, a marker, and their fingers, they constructed a homemade test tube, marking the thickness of one of their fingers consecutively on the glass from the bottom to the top edge of the glass.

3) 4)

They filled 3 trays with soil and put them on a table, resting them on the tilters (6 notebooks for the high slope, 3 for the medium slope and 0 for the tray without slope) and leaving the lowest end of the trays at the edge of the table to be able to collect the overflowing water without any problem. They poured a certain amount of water into the watering can and with it Violeta watered one of the trays while Clara, very attentive, collected in a container the water that was not absorbed by the earth and exceeded the tray. Performed this same action in the remaining trays, always using the same amount of water to irrigate.

Then, with the help of the homemade cylinder, they measured the amount of water that Clara collected at the end of each tray and recorded it in the field notebook.

6) 7)

Repeated steps 3, 4 and 5 twice more, and once the data was obtained, they transferred it to the following table:

To see the results of the experiment more clearly, they made the following bar graph on cardboard and stuck it on the wall to show it to Lihuén and reflect on the experience together:

Reflection:

To begin the reflection, Lihuén asked them: what results did you obtain in this experiment?

The girls looked at the graph with their results and after a few seconds Clara said:

* In the trays that were steeper, more water spilled than in the other trays, and in the trays with no slope, no water spilled at all. That means that the soil in the trays with a steep slope absorbed less water —continued Violeta— and that the soil in the trays without a slope absorbed all the water.

Very good! —said Lihuén encouraging them— and what relationship does that have with what you observed in your small plot?

* Mmmm… I know! —answered Violeta very animatedly—, the earth that is in the upper part of the mound is dry because the water doesn't stay there. Gravity causes the water to flow up the lowest part and, as there is no slope there, the earth can absorb it, which is why it is humid.

Great! And what else did you see in her experiment? —the Rara asked.

* Eeeee… We also saw that the water from the trays that had a steeper slope dragged a lot of earth when going down, and it was very cloudy. In the trays with a medium slope, it dragged little soil, and it was slightly cloudy, while in the trays with no slope, the water did not drag any soil —dijo Violeta.

Yes! —Clara exclaimed enthusiastically— then when there is a steep slope, water is lost and land is lost. I remember that teacher Salvatierra told us that when you lose the part surface of the earth is called erosion and that is bad because the most fertile part of the soil is there, there are the nutrients that plants need to live.

— But how clever these little girls are! — Lihuén encouraged them— Surely you remember from your history classes, that the indigenous peoples of the altiplano, such as the Aymara, the Atacameños and the Diaguitas quickly realized this problem with the slopes, so that to grow their food they built terraces, flat and stepped land on the slopes of the mountains, so as not to lose water and soil, elements so necessary for the life of the plants they cultivated.

—How wonderful! Now I do understand about the famous terraces! —Violet said happily.

—Very good job girls!" Do you see that the scientific method was not so terrible? Now that you know the steps of the inquiry cycle, you will be able to answer many of your questions scientifically —said the bird Rara getting ready to fly.

—But don't go yet! —the girls shouted in chorus.

—My homework is done, trust you and, as good scientists, don't forget to share what you know... See you soon... —Lihuén said, taking flight.

After this experience, Violeta and Clara were very happy and enthusiastic about science, so much so that they always looked for the opportunity to observe, ask questions and try to answer them, and, of course, share with their friends this beautiful way of seeing the world.