Misconceptions in chemistryPresentation Transcript
Misconceptions in Chemistry Particulate Nature of Matter Amelia E. Punzalan University of the Philippines National Institute for Science and Mathematics Education Development September 2012
This presentation is based on the book chapter: Particulate Nature of Matter by Amelia E. Punzalan and Elizabeth L. Marasigan inAddressing Misconceptions in Mathematics and Science edited by Josefina G. Belen, Aida I. Yap, Ester B. Ogena and Merle C. Tan.The book is published by the University of the Philippines NationalInstitute for Science and Mathematics Education Development and the Department of Science and Technology - Science Education Institute in April 2008. The book is UP NISMEDs contribution to the centennial celebration of the University of the Philippines. Communications may be sent to: email@example.com
Particulate Nature of Matter Matter is made up of discrete particles. These particles are called atoms and molecules. There are empty spaces between these particles. These particles are in constant random motion.
Matter is made up of discreteparticles.SURVEY:Draw how air, water, and sugar would appearthrough a very powerful magnifying glass.
Atoms and MoleculesAn atom is the smallest particle of an element thattakes part in a chemical reaction.An element is made up of one kind of atoms. An atomconsists of a nucleus and the surrounding electrons.The nucleus contains protons and neutrons.
Atoms and MoleculesA molecule is the smallest particle of a substancewhich can exist freely with all the characteristics bywhich the substance is recognized The substancemay be an element or a compound.
Atoms and MoleculesA compound is made up of molecules that are alikeand contain more than one kind of atoms (at a laterstage, students will learn that some compounds aremade up of ions).
Students’ misconception about atoms and moleculesThey either equate atoms with molecules or do notrecognize the hierarchy between molecules andatoms. They seem to confuse one for the other andcould not distinguish one from the other.
Sample ResponsesAtomsElla, 3rd yr student: Atom is the simplest form of matter.Examples: proton, electron.Rico, 4th yr student: An atom is composed of small spheressurrounded by molecules.Ed, 3rd yr student: These are small particles in the middleof axis. Example: nuclear
Sample ResponsesMoleculesEster, 3rd yr student: The particles in a particular atom.Examples: hydrogen, oxygen.Ria, 4th yr student: A molecule is the smallest part.Romel, 3rd yr student: Smaller particles that can be seen inmicroscope. Example: bacteria, fungi
Empty space between particlesResearch on student conceptions revealed that eventhough some students recognize the particulate natureof gases, they still resist the notion of empty spacebetween the particles (Whitfield, 2006). Studentswould therefore, find it difficult to comprehend the veryconcept of a void in space in a solid in discussionsabout the atomic level structure of crystalline solids.
Students’ misconception about the space between moleculesStudents think that there has to be something in thespace between particles. They have difficultyaccepting the notion of an empty space. Studentshold the view that any “empty” space must containair, dust, and other gases.
Students’ misconception about the space between moleculesEvidenceMost of the students mentioned that a solid substanceis made up of only one kind of particles and that thereis no empty space between them. They explained theiranswer by stating that no place is completely empty.
Particles are in constant random motion.That matter is made up of moving particles is a keyidea of the kinetic theory. The theory explains thetendency of gases, liquids, and solids, to spread(though very slowly in the case of solids) in alldirections.
Explanations on three familiar events:Event 1: A toy balloon becomes smaller and softerafter two days.Event 2: Without stirring, ink/food color drop spreadsevenly in water.Event 3: Bagoong or perfume smells.
Misconceptions about the motion of particlesInstance 1: Gas moves through tiny pores in the rubber balloon.Students’ responses:“Espiritu” is lost.Powder is no longer effective.Air sticks to the hand of the player.Air is evaporating.Air is compressed.
Misconceptions about the motion of particlesInstance 2: Liquid diffusion (ink spreading in water)Students’ responses:Something is pushing the ink.Ink follows shape of bottle.Ink atoms are lighter than water.Ink is colored.They just spread.Water is evaporating.There are spaces between molecules.
Misconceptions about the motion of particlesInstance 3: Gas diffusion (odor spreading in the room)Students’ responses:Odor is caused by the fish/perfume.It always smells.There is air in the bagoong/perfume.It is spreading in air.There is evaporation and mixing in the air.There are open spaces in the air.
Suggestions:1. Use suitable metaphors, modes, and analogies to make the idea more experiential. The following might be good analogies of random intrinsic motion: Random, frenzied movement of players in the heat ofa basketball tournament. Fast, random movement of bees in a disbursedbeehive.
Suggestions:2. Give more examples for students to see and from which intrinsic particle motion can be inferred. The diffusion of india ink or dye in water can beobserved through a microscope. The colloidal particles areseen to move around in a constant jerky dance.
Suggestions:3. Allow students to discuss in groups the explanations for the three instances given in this study. Listening to students can enhance teaching if theteacher takes time to consider the ideas students bring intothe classroom and helps them construct knowledge basedon these ideas.
References Marasigan, E.L. & Pili, A.S. (Feb. 9-10,2007). The use ofparticulate drawing in exploring students’ misconceptions on the natureof matter [CD]. Distributed during the Feb. 9-10, 2007 National SeminarWorkshop on Misconceptions in Science and Mathematics Educationheld at the University of the Philippines NISMED, Diliman, Q.C. Whitfield, M. (2006). Demonstrating void space in solids: Asimple demonstration to challenge a powerful misconception. Journal ofChemical Education, 83, 749-751.