OBJECTIVES: Observing the three varieties of rocks. Comparing rocks. VOCABULARY: level grain light (weight) glowing smooth MATERIALS: red, yellow, and also black record

Students explain rock samples.

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Mudstone through fossils

BACKGROUND: The surname of a absent reflects details characteristics. For example, obsidian will certainly resemble glass and scoria will generally be dark red v holes. Rock names also refer to a texture. For instance granite will have interlocking minerals and sandstone will have a gritty, sandy feel.

Young kids need to suffer these characteristics before they can internalize the surname of a rock. They need to describe and compare the characteristics, as they learn the rock’s name. Just knowing a surname of a absent is no enough. In this lab, student will usage their observational an abilities to classify rocks. Quite than utilizing a official classification, the focus is top top students arising their very own criteria because that rock classification.

PROCEDURE: evaluation the 3 main teams of rocks with students that they learned indigenous the Pre Lab. Be sure to tell them the there are numerous different types of rocks within each of the three groups. Brainstorm feasible terms for describing rocks v the students. define that identification and classification of one individual absent specimen is based on a selection of characteristics and criteria, and that lock will begin to learn some of this in this lab. provide each team of college student a piece of red, yellow, and also black paper. Write red = igneous, yellow = sedimentary, and black = metamorphic ~ above the board. Pass the end the absent sets. Go through each of the rocks come make certain the students placed the correct absent on the ideal color. Usage the info on every rock together outlined below. You might want to give the college student some clues of each rock, and then as soon as you testimonial the lab, you could want come add much more information.


OBSIDIAN - also known as volcanic glass. Most children recognize obsidian as the rock that plenty of Indians provided to make arrowheads. The Indians decided obsidian for the same factors that a geologist have the right to recognize it. That is an extremely hard, but much more importantly the breaks into sharp edges the easily reduced through plenty of materials. Keep in mind that broken obsidian look at like damaged glass. Obsidian occurs in practically any color, depending upon what trace aspects are present in it. Black and also brown obsidian are most common. Obsidian is one amorphous solid; that, the is a solid rock created of silicon dioxide, yet this material lacks crystalline structures. It is one of very few exceptions to the ascendancy that rocks are made of minerals.

The obsidian that is in her kit comes from volcanoes close to Clear Lake, California. Obsidian is developed when lava is cooled really quickly; that freezes prior to crystals can form. Have your students shot to identify which component of a lava flow will cool easily enough to kind obsidian (answer - the external surface or "skin" of the flow).

PUMICE - Students will certainly immediately an alert that pumice is spongy or "full the holes" or vesciular. This characteristic makes pumice exceptionally lightweight; it also floats in water (you might wish to display this to her students). It is commonly light gray come blackish-gray in color. It is conveniently broken and also has spicy edges. Favor obsidian, pumice is volcanic glass; it therefore looks glassy (especially through a magnifying glass) and also lacks visible minerals.

Pumice forms during eruptions of magma containing big quantities that gasses, such together water vapor, sulfur dioxide, and carbon dioxide. The gas "froths" the magma as it erupts, developing bubbles. This is physically analogous to opening a soda can; carbon dioxide bubbles kind in the drink as the deserve to is opened. Prefer obsidian, the magma climate cools quickly, preserving the bubble shapes. The gas often escapes, leaving many holes in the pumice. Pumice is used as an ornamental building stone. "Pumice rock" is likewise sold in beauty, beauty stores for cleaning dead skin cell from areas like feet or elbows.

SCORIA - Scoria is written of piece of volcano glass and preexisting rock fragments that ended up being incorporated into the magma as it erupted. Many scoria have pieces of basalt contained hence if deserve to look prefer a red vesicular basalt. The volcano glass looks similar to pumice but denser. Scoria is red in color, since contains much more iron than pumice. Scoria lacks big visible minerals; small ones may be the visible with a magnifying glass. Scoria is regularly sold as "lava rock" for usage as a landscaping material.

GRANITE - Granite is written of visible minerals, most commonly quartz, mica and also feldspar. Quartz looks clear and glassy, mica is black and also flaky, and also the feldspars (commonly two or more different varieties are present) room either pale pink/orange or white in color. The relatively huge size of the minerals shows that the magma that created the granite cooled slowly. This took location deep inside the earth, no on the surface, like pumice or scoria; that is a plutonic rock. Ask her students if they think granite is made of the very same minerals together basalt (no, lock cooled differently and came from a various "mother" magma). That may aid to have them imagine that the minerals in the granite to be tiny; would certainly this make them dark?, (No, they would certainly still be irradiate colored). This shows that rocks created of various minerals likely have various magma "mothers." try using the analogy that rocks are choose people, no two room the same! Granite is offered as ornamental and building stone.


CONGLOMERATE - Conglomerate is composed of pebbles, gravel, sand, and also boulders that have actually been cemented together to do a heavy rock. These products were combined naturally in rivers or in some parts of oceans and lakes. Any form of preexisting rock have the right to become component of a conglomerate.

To describe cementation, try telling student that mom Nature has a cement the she sometimes pours top top the beaches of lakes, oceans, and rivers. As soon as it hardens, it i do not care conglomerate, if the pieces room big, or sandstone, if they are small. In reality, the 2 most common cementing substances are natural solutions of calcium carbonate and also silica dioxide. Crystals of calcite and also quartz, respectively, precipitate indigenous these services in the spaces between grains, cementing the absent together.

SANDSTONE - The gritty feeling of the surface ar of sandstone hints that this absent was when sand that has been cemented together. Sandstones have quite differed compositions; some space composed entirely of quartz, and also others space mixtures the rocks, crystals and fossils. Almost any mix is possible. Sandstones hence come in a broad array the colors. By definition, the grains in a sandstone room "sand-sized"; many students will recognize this if you demonstrate "sand size" by reflecting them a bag of sand.

SHALE - Shale is composed of very small particles of mud, which have been compacted and also cemented together. Individual mud grains are very small; castle will hardly ever be visible. Shales are quite variable in color.

CHERT - Chert can range in color from white come red come brown in color and also is mostly composed that very little quartz crystals. The red color comes indigenous trace amounts of iron, and brownish tinges have the right to be resulted in by the existence of essential matter. Chert is really hard. Chert was likewise used by ind (the range called flint) because that making tools. Chert creates from the skeletons of microscope one-celled protozoa referred to as radiolarians. These are sometimes maintained in the rock, but can only be seen v a microscope. Chert forms on the ocean floor, whereby the skeletons of this organisms room deposited after castle die.

COAL - coal is a sedimentary rock written of the accumulation of vegetable issue that has actually been consolidated in between other absent strata to kind coal seams. Coal has several forms relying on the impacts of microbial action, pressure and heat end a substantial time period. Anthracite is the most compressed and also hard form; bituminous is no as hard; and lignite still has vegetable issue present.


MARBLE - marble is composed solely of huge commonly visible crystals the calcite. The gray/white bands in several of the samples are because of impurities within the calcite. Marble in reality comes in a selection of colors, including black, gray, white, and also pink. Marble, prefer all rocks that have calcite in them, fizz if you placed a weak mountain on that (usually 10% equipment of hydrochloric acid). Marble forms when a rock containing calcite in that (such as limestone) was put under high temperature and pressure conditions. Marble has been offered throughout background because that is basic to break and also to carve. Part marble (especially in Italy) is provided for that is smooth, little crystals that make it wonderful for statues. Many of the statues that Michelangelo were made native marble. Marble is additionally used as an ornamental building stone. If girlfriend live near or in a city, have your students try to find buildings made of marble. If you room in one old school, some of the bathroom stalls or floors may be make of marble.

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SERPENTINITE - Serpentinite has a smooth, soapy feel, a environment-friendly mottled color, and also a somewhat flaky texture. It is composed mainly of the mineral serpentine. Serpentinite is for this reason named since of that mottled color, which resembles the back of a sea-serpent. The geologic beginning of serpentinite is tho debated, yet many researchers agree that it developed from a rock like basalt that was put under high temperature and pressure. Serpentinite is the state rock of California. Serpentinite is provided for carving and also as an ornamental building stone.

SCHIST - Schist is written of visible minerals, greatly micas. Schists type under moderately high press conditions; this causes the normally platy mica crystals to line up, giving the rock a platy look. This is a good example for showing the characteristic "squished" look at of metamorphic rocks to her students. Have them imagine that a hefty Mother Nature sat on some rocks - look in ~ what she did!