Objective: To illustrate the differences between weathering and erosion and to strengthen understanding of these concepts.
Standards: Changes in Earth and Sky (slow erosion, weathering) and Properties of Earth Materials (physical and chemical properties of rocks and soils).
Materials: Enough bite – sized Snickers candies for all students in the classroom.
(1) Pass out one bite – sized Snickers to every student in the class.
(2) Instruct the students to put the Snickers in their mouth but to not chew or swallow them.
(3) Have the students make note of what is happening to the Snickers in their mouths as their saliva begins to dissolve it.
(4) Once the students have dissolved the candy down to only nuts allow them to chew the nuts while making continued observations of how the nuts are being
(5) Allow the students to now swallow the snickers.
Science Behind It: This demo effectively illustrates three processes that readily confuse many students. The first process illustrated was chemical weathering. This occurred because the Snickers remained in situ as chemicals of the mouth broke it down without movement or work. This part of the demo can be compared to such things as acid rainwater dissolving limestone, for example. The second process was mechanical or physical weathering and this occurred as the students worked to break down the nuts of the candy through chewing. A real life example of this process would be any situation where something is broken down through the direct action of heat, water, ice and pressure. The third process in this demo was erosion and occurred as the students swallowed the snickers. This illustrates erosion because it involves the movement or transportation of materials from one place to another (from the mouth through the esophagus and into the stomach). It is important for teachers to distinguish between weathering and erosion in this demo as these concepts are usually misunderstood by students. The main difference between erosion and weathering is that erosion involves the movement and transportation of sediments from one place to another while weathering happens in situ and does not involve transportation.