Summary

In this activity, students will view an animation that explores the idea that everything is made of atoms, and that since atoms are so extremely small, even small objects contain vast numbers of atoms. They will see several examples to illustrate this point. Then they will be given a brief overview of the evolution of how people thought about atoms from the ancient Greeks through Dalton.

Grade Level

Middle School, High School

Objectives

By the end of this activity, students should be able to:

• Identify that all matter is made of one or more of the 118 types of atoms listed on the periodic table.
• Begin to understand how small atoms are, and how many of them are in even small objects.
• Explain some of the ways different people have thought about matter throughout history.

Chemistry Topics

This activity supports students’ understanding of:

• Matter
• Atoms
• Atomic scale
• History of the atom

Time

Teacher Preparation: minimal
Lesson: 10-30 minutes

Materials

• Computer and projector with internet access
• https://teachchemistry.org/classroom-resources/atoms-the-building-blocks-of-matter
• Student handout

Safety

• No specific safety precautions need to be observed for this activity.

Teacher Notes

• All of the animations that make up the AACT Animation collection are designed for teachers to incorporate into their classroom lessons. Intentionally, these animations do not have any spoken explanations so that a teacher can speak while the animation is playing and stop the animation as needed to instruct.
• If you assign this to students outside of class time, you can create a Student Pass that will allow students to view the animation (or any other video or ChemMatters article on the AACT website).
• We suggest that a teacher pause this animation at several points, including when questions are posed before the answers are revealed, or watch it more than once to give students the opportunity to make notes, ask questions, and test their understanding of the concepts presented. The student activity sheet can help activate students’ prior knowledge, guide them through the animation, and provide a chance for after-viewing reflection and optional extension questions.
• This animation was designed primarily with a middle school audience in mind, but it could also be used in an introductory high school chemistry course. It does not address ideas in modern atomic theory beyond Dalton’s “Billiard Ball Model” from the early 1800s (so no subatomic particles are mentioned), but it could be used to introduce a unit on atomic theory. With this in mind, more advanced ideas such as dark matter and dark energy are not addressed when discussing the makeup of the universe.
• If you have already taught about measurements and unit conversions and wanted to practice some conversions, you could have students verify the calculations used to arrive at the numbers given in the animation (the atoms in a drop of water, the size of a penny if atoms were tennis ball-sized) with the extension questions. Students will likely need to look up some of the conversion factors if they don’t know them off-hand. See the answer key for sample calculations.
  • To dig deeper into scale, there is a really cool resource, developed by high school students, called The Scale of the Universe, which allows you to zoom in and out to the smallest and biggest things in the universe – all the way into a string theory string and all the way out to the entire observable universe itself! It includes measurements and informational blurbs on objects at various size levels. My students have loved exploring it. It is also available as an iOS app.
• The “four elements” (fire, air, earth, and water) theory of matter stuck around for quite a while before the idea of tiny particles became more widely accepted. Famous philosopher Aristotle was a believer of the four elements theory. As he was perhaps one of the original “influencers,” his views influenced a lot of other people. You could use this to draw a social studies connection and discuss the role influential public figures can play in science, for better or worse, using the last extension question, or something similar.
  • It is important to note that Greek philosophers were not experimentalists – they thought a lot about their natural world but did not often use the scientific method to test their ideas out. You could discuss the important role of the scientific method, repeating/verifying experiments, and peer review in the modern scientific process.
• Be sure that your students understand the difference between the ancient Greek notion of “atoms” and the modern understanding. While both propose that atoms are indivisible, we now know that atoms are not unique to each type of substance (ex: there are no “stone atoms”) instead there are 118 elements that combine in different ways to create all the different substances. (So in this sense, the Greek concept of atoms might be likened to the modern-day molecule – the smallest unit of something that retains that substance’s properties. It can be broken apart further into its component atoms, but not without changing the substance.)
• The image used for carbon dioxide is dry ice – students may be more familiar with carbon dioxide as an invisible gas, so seeing carbon dioxide in this form might need some explaining.
• There are now 118 elements on the periodic table – we do not distinguish between naturally occurring and synthetic elements. However, if you wish to discuss this with students, you can talk about the first 92 elements occur naturally (except technetium, #43!) and elements after atomic number 92 are produced in laboratories (although a few were found in very, very small quantities in nature after being synthesized).
• Classroom resources from the AACT Library that may be used to further teach this topic include:
  • Simulation Activity: Building an Atom
  • Unit Plan: The Periodic Table Unit Plan
  • Lesson Plan: Modeling Atomic Theories with Food
  • Lesson Plan: Acting Out Atomic Structure
  • Activity: Atomic Structure RAFT
  • Project: Elemental Art: A Visual Periodic Table