Author:
VCU STEM Project 3, VCU STEM Project 1, VCU STEM Project 2
Subject:
STEM/STEAM, Science, Matter
Material Type:
Lesson Plan
Level:
Middle School
Grade:
8
Provider:
Virginia Commonwealth University (VCU)
Tags:
  • Atoms
  • Matter
  • Physical Science
  • Science
  • VCU CISTEME STEM
  • VCU STEM Project
  • License:
    Creative Commons Attribution Non-Commercial
    Language:
    English
    Media Formats:
    Text/HTML

    The Evolution of the Atomic Model

    The Evolution of the Atomic Model

    Overview

    As technology has evolved over time so has the understanding of the structure of the atom. This module focuses on how the model of the atom has changed over time using The Atomic Theory Timeline including the historical contributions of the scientists involved. This module was developed by Tracey Nipper as part of a Virginia Commonwealth University STEM initiative sponsored by the Virginia Department of Education.

    Introduction

    As technology has evolved over time so has the understanding of the structure of the atom.

    This module focuses on how the model of the atom has changed over time using The Atomic Theory Timeline including the historical contributions of the scientists involved. 

     

    Overall goal of the model

    The student will distinguish and describe similarities and differences of 2D atomic models from earliest model to the most modern model.

    The students will place the historical contribution of each Atomic Theory scientist into an atomic theory timeline, place the correct model of the atom with each scientist, and list the characteristics of each model.

    This goal supports Virginia SOL PS.2 The student will investigate and understand that matter is composed of atoms. Key ideas include:

    a) our understanding of atoms has developed over time.

     

    Prerequisites for this module:

    Prerequisites for the module include assessed ability to locate the location of aton structures (nucleus, energy levels, electrons)

    Materials:

        Small craft pompoms (or dyed cotton balls)

        Wire clothes hangers

        String

        Sticky labels (like address labels)

        Index cards

        Sharpies

        Hot glue gun/hot glue sticks

    Scaffolds

    It might be necessary for some students to receive small group/1:1 instruction for memorization of scientists into their correct location on the timeline. It might also be necessary for some students to work with individual table sorts to place the atoms in order.

     

    Engagement

    Begin this lesson by reminding students about the atom and its structure.  Possibly have students come to the board to label an atom (nucleus, energy levels, electrons) or have students complete a table sort on atom structure to do a quick formative assessment to make sure that students are prepared to move forward with placing atom models on The Atomic Theory Timeline.  Remind students that even though we are able to draw a model of an atom now, that in the past there was no technology for scientists to make these discoveries.  They made their discoveries based on inferences. 

    Discuss inferences with students.  Explain any time in your life when someone has made an inference about you such as, “You must be smart because you wear glasses.”  Have students volunteer to share out any time in their life when they have experienced people making inferences about them (students might site race, religion, income status, etc.)

    Also, discuss that everything around us is made of matter (atoms).  However, states (solid, liquid, gas, and plasma) and types (elements, compounds, and mixtures) will be discussed after The Atomic Theory Timeline.

    Discuss the question, “Do you think that our understanding of the structure of the atom has changed over time?”  Have students form opinions and share out.  Come to the conclusion with the students that our understanding of the structure of the atom has changed over time because of the invention of technology and because of the historical contributions of previous scientists. 

    After discussing the question, take out a box that has multiple small holes on all sides.  Place varying size marbles in the box (make sure that two of the marble sizes can fit through the holes.  At least one other marble size should be bigger than the holes.  Shake the box around into a larger box.  Have students observe the marbles that come out the holes.  Shake the box again until no marbles come out of the holes.  Discuss how some of the marbles are outside of the box and that others are inside of the box.  Much like the structure of the atom.

    Exploration

    Students will explore the particle model before beginning their atomic theory timelines.  Students will be grouped into groups of 3-4 students.  Each group will receive a beaker with 200 mL of water.  The teacher will visit each group placing 5 drops of blue food coloring into the water.  Students should record their observations of the movement of the food dye.  Through these observations a class discussion can be conducted about the movement of particles (the food dye) through another substance (water).  This will lead to the idea that the atom is a particle that is in motion.

    Students will be grouped into groups of 3-4.  Students will receive Atomic Theory Sort Cards (attached), already cut and in individual groups, with illustrations of the different models of the atom from earliest model to most modern model.

    Students will sort the cards into a timeline using prior knowledge of atom structure.  

     

    Students will then justify why they placed the atoms into their timeline.  The teacher will complete small group instruction placing the atoms into the correct timeline (if needed) and completing an oral characteristic review with each group asking the following questions because students should have noticed a pattern of nucleus/no nucleus and electrons/no electrons and energy levels/no energy levels.

    1. Which atom illustrations have a nucleus? (Once sorted into nucleus/no nucleus go to question #2)

    2.  Which of the no nucleus illustrations contains electrons?  (Once separated, move to #3)

    3. Which of the nucleus atom illustrations shows no pattern in the energy levels (empty space)?  

    4. Which of the nucleus atom illustrations shows a pattern of energy levels?

    5. Then the modern model should be left as #5 on timeline.

     

    Explanation

    Whole class instruction:  Have students share out their “take-aways” from the small group table sort/small group instruction.  Provide students will an outlined copy of Atomic Theory Timeline Notes (attached).

    During the Notes Review discuss how our knowledge of the structure of the atom has changed over time due to the invention of technology and historical contributions of each scientist.

    Students will use completed notes to complete Atomic Model Worksheet (attached).

    Elaboration

    Students will further explore the atomic theory models by completing a jigsaw activity.

     

    1. Before students begin exploration:  The teacher will show the students a scoop of chocolate chip ice cream.  Students will observe the round sphere.  Students will observe the vanilla ice cream and the chocolate chips.  The teacher will ask the students to describe which scientist’s atomic model the scoop of ice cream reminds them of from their research in Lesson One.  Students will answer (answer is Thomson).  Teacher will then slice the ice cream scoop sphere in half to show how the chocolate chips are embedded in the ice cream like Thomson thought the electrons were embedded in the solid atom.  This model will allow students to begin to visualize and think about the structure of each scientists’ model.

    2. Students will be placed into groups (divide your class size by 5 to determine group size).

    3. Once groups have been set, explain directions for jigsaw activity.  Assign each group a scientists’ atomic model.  Students will work cooperatively to complete the Atomic Theory "Phasebook" Pages (attached).

    4. Students should choose 1 student in their group to be the jigsaw-teacher.

    5. This one student will move to the 4 other groups reviewing their assigned scientist atomic model with the other groups.  Set a time to switch groups every 10 minutes (estimate).

    6. While the jigsaw student teacher goes to each group, students in those groups will complete the Phasebook Jigsaw Summary Page (attached).

    7. Once each group has completed their entire jigsaw page, come together as a whole class review to go over their take-aways from the Jigsaw activity

    8. Students will complete Atomic Theory Model Graphic Organizer Grade (attached) as an assessment of any needs for reteach.

    Evaluation

    Atomic Theory Model Summative Assessment (attached).

    Review

    Students should be able to identify each scientist's atomic theory model using illustrations and descriptions. 

    Students should be able to continue to identify the parts of atomic structure.

    Students should be able to explain that our understanding of the structure of the atom has changed over time with the invention of new technologies and the historical contributions of the scientists.