Sand Honor
Nature Study
Requirements
- What does the word sand mean? Give the name of 2 types of sand.
Answer: Sand is loose granular material, formed by small grains of rock and minerals (mainly quartz), with a size between silt and gravel (about 0.06 to 2 mm). Two types: beach sand (marine) and river sand (fluvial) — one may also mention desert sand and construction sand. — Sand is nothing more than rock fragmented into grains — knowing it helps to understand its many uses.
- Present the origin of sand and its mineral content.
Answer: Origem da areia: a areia nasce da fragmentação das rochas. Pela ação do intemperismo (variação de temperatura, água, gelo, vento, raízes e reações químicas) as rochas se quebram em partículas cada vez menores, que são transportadas por rios, ondas e vento e depositadas em praias, dunas, leitos de rio e fundo do mar. Quanto mais longe e por mais tempo viajam, mais arredondados e selecionados ficam os grãos. Conteúdo mineral: o mineral mais comum na areia é o quartzo (sílica, SiO2), por ser muito duro e resistente a desgaste; também aparecem feldspato, mica, magnetita, e, em areias de origem biológica/marinha, fragmentos de conchas e corais ricos em carbonato de cálcio (areia calcária). Areias vulcânicas escuras contêm minerais como basalto, olivina e magnetita.
- What is the difference between sand and soil?
Answer: Sand is only a mineral component, formed by grains of rock (especially quartz), with no organic matter. Soil is more complex: it is the mixture of mineral particles (sand, silt, and clay) with organic matter (humus), water, air, and living beings — that is why soil sustains plants, while pure sand, on its own, retains little water and few nutrients. — Sand is only mineral; soil is a living mixture of minerals and organic matter — that is why soil is fertile and sand is not.
- What do the size of the sand grain, its shape, surface, and its fragmentation tell us?
Answer: These characteristics tell the 'story' of the sand: the size of the grains indicates the energy of the transport (water/wind); rounded grains with a polished surface indicate that they rolled for a long time or a long distance (more 'mature'), while angular grains are 'newer', little transported; the degree of fragmentation and of sorting shows how and for how long the sand was carried and worn down. — The shape and the wear of the grains reveal where the sand came from and how long it traveled to get there.
- Define and explain the usefulness of each one:
- Glacial
- Calcareous
- Quicksand
- Sand for making glass
- Molding sand
- Polishing sand
- Construction sand
- Filtering sand
- Furnace sand
- Beach sand
Answer: 1) Glacial: sand left by glaciers when they melt; used in geological studies to understand the movement of the ice. 2) Calcareous: rich in calcium carbonate (ground shells and corals); used in gardens and in the correction (liming) of the soil. 3) Quicksand: water-saturated sand that loses its firmness when stepped on; important to know about for safety. 4) Glass-making sand: very pure quartz sand; it is the raw material of glass. 5) Molding sand: used to make molds in metal casting. 6) Polishing sand: abrasive, used for sanding and finishing (polishing) surfaces. 7) Construction sand: mixed with cement to form concrete and mortar. 8) Filtering sand: used in water filters, it retains impurities and particles. 9) Furnace sand: resistant to high temperatures, used in casting molds. 10) Beach sand: coastal sand, used in leisure and, sometimes, in construction. — Each type of sand has a composition that defines its use — from glass to water filtration and construction.
- Memorize Genesis 22:17 and Proverbs 27:3.
- Examine 5 types of sand specimens with magnifying lenses and observe the various characteristics.
- Make a collection of 10 varieties of colored sands and give the name of the locality from which you took them. (Note: Bring small bags, a pencil, and a small spoon or scoop to collect the sand. Present them in small glass jars/bottles).