Teaching and also Learning Focus

In the previous 2 investigations, students examined few of the physical properties the different types of rocks. They started classifying rocks follow to their different characteristics. In this investigation, student think around how rocks readjust through time. They consider the malfunction of rock into smaller and smaller piece through procedures that jointly are recognized as weathering. The specific procedure that students study in this investigation is abrasion, the activity of rocks and sediment grinding against each other and also wearing away exposed surfaces. In nature, abrasion occurs as wind and water rush over rocks, leading to them come bump versus one another and transforming their shapes. Rocks come to be smoother as rough and also jagged edges break off. Students run a design of this procedure by shaking sugar cubes and also gravel with each other in a plastic container. The sugar cubes come to be smoother together their edges break off once they collide in the container.

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Materials Needed

For each student:

2-3 street cubes2-3 piece of gravelsmall plastic container with a lidmagnifying glasspaper (e.g. Newsprint) come cover desktops

For instructional purposes:


This examination is generally thought about safe to perform with students. Perform not provide glass containers to students due to the fact that the shower of the gravel could cause them to break. Students should be reminded no to eat the sugar cubes. Also, review the examination for your details setting, materials, students, and conventional safety and security precautions.

Setting the Scene

Most probably, students recognize that in nature rocks exist in different sizes, native exposed mountain sides and also plateaus to boulders to gravel to seed of sand. The processes by which rocks failure into smaller and smaller pieces, however, may be brand-new to students. Begin the examination by questioning students about the assorted sizes the rocks lock may have experienced or seen.

Describe the different sizes of rocks you check in the vault investigations.How big can rocks in nature get? What are some examples of large rocks? Where can they it is in found?How little can rocks in nature get? wherein are small rocks found?

Have your students discuss these questions, very first in pairs, then groups and also then as a totality class. Document their answer on a flipchart the you deserve to refer to transparent the investigation.

Presenting the investigation Question

After the scene is set, present your students come the examination question: “How execute rocks break down into smaller pieces?

Have her students discuss the inquiry in pairs, then in groups, and also then together a totality class. Document their answers on the flipchart.

Have your students brainstorm ideas around how this investigation question might be investigated.

How would certainly you design an experiment that can be provided to test the examination question?What materials would be needed?What would you have to do?What would be measured?How lengthy would the experiment take?

Tell your students the they will be investigate this question and also at the end of their research they will certainly be may be to administer reliable answers.

Assessing What your Students currently Know

Students will probably have had some personal experiences of breaking rocks apart, such together by hitting a rock through a hammer or throwing a absent onto a hard surface. Some may be able to transfer this understanding to a natural setting, such as rocks grinding against each various other in a rockfall or landslide. Here are some initial inquiries that your students have the right to discuss, in pairs, in groups, and as a totality class:

What happens when rocks smash right into each other?What might reason rocks to smash or grind against each other?Do every rocks rest apart in the exact same way?Some rocks can have stormy edges while others are rather smooth? What could create a smooth rock?

Have your students re-publishing their concepts with the class and also record them together a perform on the flipchart.

Have student think around what lock would favor to learn around the failure of rock into smaller and smaller pieces. Document their principles on the flipchart together a list referred to as “Questions we have about how rocks breakdown.” This perform will provide further insights right into what your students know, and likewise what castle would like to know. By the end of the investigation, few of these concerns will most likely be answered.

Exploring the Concept

Provide the products to the students.Instruct students to cover their desktops v paper.Ask students to place their sugar cubes in the little plastic container and also to near the container v the lid.Ask students come predict just how the sugar cubes will change after they have been shaken within the container for 1 minute. Students must record your predictions ~ above the monitoring sheet.Students shake the container v the sugar cubes within for one minute.Instruct college student to open their containers and to negative the products inside onto their desktops.Students use their magnifying glasses to re-examine the sugar cubes. They have to record their monitorings on the observation sheet.Ask student to put the sugar cubes back into the container together with the gravel provided. Ask them to close the containers v the lids.Ask students come predict how the street cubes will adjust after they have been shaken within the container with the gravel for 1 minute. Students need to record their predictions top top the observation sheet.Students shiver the container a 2nd time because that 1 minute through the street cubes and also gravel inside.Students usage their magnifying glasses to re-examine the street cubes. They must record their observations on the observation sheet.Ask student to develop a conclusion about why the cubes readjusted as they go after every shaking.Hold a class discussion around what the student observed. Ask college student the complying with questions. Record their answers on the flipchart.How go the sugar cubes adjust after the first shaking? What may have caused this changes?Did the second shaking with the gravel reason the sugar cubes to look an ext worn? Why?Which shiver had more or less “crumbs”? Why?How did your predictions to compare to your results.Introduce come students the term weathering. Ask lock the adhering to questions:What might cause rocks in nature to it is in shaken together much like just how you shook the street cubes along with the gravel?How long do friend think this kind of weathering takes? Why?

Applying Students" Understanding

Show the images of Weathering photos to your students. Have your students price the adhering to questions as concerned the pictures:

Describe the surface ar of the rocks in every picture. Room the rocks smooth or rough?

You could also have student conduct one more model of abrasion. But, rather of making use of sugar cubes, lock use little pieces of broken limestone, all about the very same size. They put the pieces into a plastic container filled with water. Lock shake the container because that a total of 700 shakes. After every 100 shakes, lock observe just how the forms of the rocks change. Have actually students predict just how the rocks will adjust before they begin the task to watch if they room able to apply what they learned in the sugar cube activity to this new situation.

Revisiting investigation Question 3

Complete this examination by asking your students to reflect top top this question and how their answers might have changed as a result of the investigation. Because that example, they have to note the rocks break down into smaller and smaller pieces as they bounce, collide, and also grind against each other. Castle also readjust shape, becoming rounder and more smooth.

Digging Deeper

The complying with passage provides much more detailed info related to this examination that you may pick to define to her students.

Physical Weathering

Physical weathering, sometimes called mechanical weathering, has all the processes which rest rocks personally without an altering their chemistry composition. Adhering to are instances of physics weathering processes.

Rock Abrasion

Rock abrasion occurs as soon as rocks collide through one an additional or rub versus one another. Collisions, if they are solid enough, can cause pieces of absent to break into two or an ext pieces, or cause little chips to be damaged off a large piece. Once two pieces of rock space rubbed together, the mineral seed in the rocks deserve to be damaged away from the rock surface. Rock abrasion occurs frequently in landslides whereby pieces of absent slide past one one more as the mass moves downhill. It likewise occurs in ~ the base of a glacier whereby pieces of absent that are frozen right into the ice space dragged follow me beneath the glacier. In fast-moving streams and also rivers, pieces of rock that are being relocated by the flow rub against one one more and against other pieces relaxing on the flow bed.

Ice wedging

Ice wedging describes the repeated freezing and melting of water within tiny cracks in rocks close to the surface. The water in the crack freezes as the temperature drops listed below freezing. Together the water freezes, that expands. This expansion exerts tremendous pressure on the neighboring rock and acts like a wedge, making crack wider. After repeated freezing and thawing of water, the rock division apart.

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Plant roots

Plant root can flourish in cracks. Together the tree grows, the root becomes larger. The pressure of a confined growing root deserve to be substantial. This pressures make cracks in the rocks larger, and, as roots grow, they deserve to break rocks apart.