To explore atomic structure.
This lesson is the first of a four-part series on static electricity. These lessons are meant to help students understand that static electricity is a phenomenon that involves positive and negative charges.
An understanding of static electricity must begin with the concept that all matter is composed of atoms, and all atoms are composed of subatomic particles among which are the charged particles known as electrons and protons. Protons carry a positive charge (+), and electrons carry a negative charge (-). The number of electrons in an atom—ranging from one up to about 100—matches the number of charged particles, or protons, in the nucleus, and determines how the atom will link to other atoms to form molecules. Electrically neutral particles (neutrons) in the nucleus add to its mass but do not affect the number of electrons and so have almost no effect on the atom's links to other atoms (its chemical behavior).
To further understanding about static electricity, you should help your students to make connections between their day-to-day experiences with static electricity—such as lightning, receiving shocks after shuffling across a carpet, taking clothes that cling to each other out of the dryer, combing their hair in the wintertime—with the static activities conducted in the classroom. Ask them to try to describe and explain their everyday experiences with static in the terms they are learning: repel, attract, static charge, electron transfer. It is important that students grasp the concept that oppositely charged objects attract each other and like charged objects repel each other. It is less important that they are able to recall which materials tend to acquire negative or positive charges.
When two different materials come into close contact, for example, felt rubbing against a balloon or two air masses in a storm cloud, electrons may be transferred from one material to the other. When this happens, one material ends up with an excess of electrons and becomes negatively charged, while the other ends up with a deficiency of electrons and becomes positively charged. This accumulation of imbalanced charges on objects results in the phenomena we commonly refer to as static electricity.
When students first begin to understand atoms, they cannot confidently make the distinction between atoms and molecules. Students often get the idea that atoms somehow just fill matter up rather than the correct idea that the atoms are the matter. Middle-school students also have trouble with the idea that atoms are in continual motion. Coming to terms with these concepts is necessary for students to make sense of atomic theory and its explanatory power. (Benchmarks for Science Literacy, p. 75.)
In Static Electricity 1: Introducing Atoms, students are asked to review websites to learn about the atom's basic structure and the positive and negative charges of its subparticles. This lesson lays the groundwork for further study of static and current electricity by focusing on the idea of positive and negative charges at the atomic level. Due to the amount and complexity of the information related to this topic, students will gain an understanding of these concepts over time. It is important that they explore this topic in a variety of contexts.
Static Electricity 2: Introducing Static Electricity helps expand students' concepts about atoms and how they relate to static electricity. In this lesson, students perform some simple experiments, creating static electricity to demonstrate how opposite charges attract each other and like charges repel each other. Then, students explore a website that further explains these concepts.
Static Electricity 3: More About Static Electricity helps expand students' concepts about atoms and how they relate to static electricity. In this lesson, students explore a website to investigate concepts related to static electricity. Then, students perform experiments in which they create static electricity and demonstrate how opposite charges attract each other and like charges repel each other.
Static Electricity 4: Static Electricity and Lightning introduces students to concepts about lightning and how they relate to static electricity. In this lesson, students explore a variety of websites to learn about lightning and then explain in their own words what causes lightning and how it is related to static electricity.
Before exploring the websites introducing students to the structure of matter and atoms, conduct a general discussion to familiarize them with some basic terms and concepts.
Ask students these questions:
- What do you think everything is made of?
- What is matter? (Matter is anything that has weight and takes up space.)
- What is mass? (Mass is a quantity or an amount of matter.)
- What are atoms? (Atoms are one of the tiniest particles of any material or element. Atoms are the building blocks of matter.)
- How can scientists guess what atoms look like? (Scientists use special tools to be able to "guess" what atoms look like. They also use a special microscope called an electron microscope that gives them ideas about what atoms look like. They do experiments to understand how atoms behave with each other.)
Begin this part of the lesson by telling students that they will explore webpages to learn more about the nature of atoms, including electrons, protons, and neutrons.
Distribute the Introducing Atoms student sheet. Ask students to answer the questions as they use their Introducing Atoms student esheet to explore the webpages. Students can use their notes during the class discussion.
- Structure of Matter—Instruct students to read only the first four pages.
- All About Atoms—This resource has only a couple of pages to it. Students can click on a particle to learn more about it.
After students have explored the resources, lead them through a discussion of the questions they answered on their student sheets:
- What makes the elements in the Periodic Table different? (Each element has a different number of electrons, protons, and neutrons.)
- What is the name for the center of the atom containing the protons and neutrons? (Nucleus)
- What kind of electrical charge do protons, electrons, and neutrons have? (Protons have a positive charge, electrons have a negative charge, and neutrons do not have any charge.)
- What does it mean if an entire atom has a neutral charge? (It has the same number of protons and electrons.)
- Describe the movement of the electrons. (The electrons move in a random orbit.)
- What can happen to the atomic particles when you rub two objects together? (It is possible to transfer some of the outer electrons from one object to another.)
- What happens to an object that loses electrons? (An object that loses electrons has a deficiency of electrons, leaving it positively charged.)
- What happens to an object that gains electrons? (An object that gains electrons is negatively charged.)
- What happens when an object with a positive charge and an object with a negative charge are near each other? (The two objects will attract each other because of the electric force between them.)
- What causes the particles of the atom to stay together? (The particles have opposite electrical charges and are attracted to each other, causing the particles of the atom to stay together.)
Assess students’ understanding by asking them to define in their own words what an atom is. Students should be able to explain that all matter is made up of atoms that are so small they can only be seen with special microscopes. In each atom there is a nucleus that consists of neutrons and protons. Electrons move around the nucleus.
Ask students to draw a picture of an atom and to label the parts. Students should be able to draw an atom and label the nucleus, protons, neutrons, and electrons. There should be an equal number of protons and electrons.
To further explore topics related to atomic charges and static electricity, continue with these Science NetLinks lessons:
- Static Electricity 2: Introducing Static Electricity
- Static Electricity 3: More About Static Electricity
- Static Electricity 4: Static Electricity and Lightning