To help students understand concepts related to static electricity, based on a single example: lightning.
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 asking students to explore the websites related to lightning and static electricity, discuss with them their current knowledge of the topic.
Distribute the Static Electricity and Lightning activity packet. Students should complete Part 1 of the packet at this time. Ask students to write down their answers using their own words. Inform them that they will revisit these answers later in the lesson, after they complete their webquest. Discuss with students how they answered the questions from Part 1 of their activity packet.
In this lesson, students will use their Static Electricity and Lightning student esheet to go on a webquest, exploring the following websites to understand more about lightning and static electricity:
- Static Electricity and Lightning
- Basics of Static Electricity
- Static Electricity Sparks
- Uses for Static Electricity
Have students work together in pairs or small groups so they can help each other understand the facts and concepts in the Internet exploration.
After students complete Part 2 of the activity packet, lead a discussion to help them process the ideas. Below are the questions from the packet with suggested responses.
- Explain what causes lightning. How does the principle of opposite charges attracting help to produce lightning? (Air, water droplets, and even ice crystals rub violently against each other inside a thundercloud, creating two opposite kinds of electrical charge: negative and positive. When the attraction between charges is so strong that they push through the air towards each other, you have lightning.)
- Draw a diagram to illustrate what happens to the electrons in the clouds and on the ground during a lightning storm.
- What is a simple way to estimate how far away lightning is from you? (Light travels faster than sound. If you see a flash of lightning, count the seconds until you hear thunder. Divide the number you get by five, and that tells you how many miles away the lightning is.)
- Describe some of the effects static electricity has on matter. Use some examples from your everyday life. (Static electricity can cause materials to stick or cling together. For example, you can observe "static cling" on clothes coming from the dryer. It can cause materials to repel or move apart. You can see your hairs repel each other after combing on a dry day. It can create sparks that fly from one object to another. For example, after you walked across a rug, you can observe a spark jump from your finger just before you touch the doorknob. You can also see extremely big sparks when you see lightning during a thunderstorm.)
- Describe how an electroscope works to detect static electricity. (When static electricity is present, charges go down the rod of the electroscope and collect on the foils. Since each foil collects the same type of charge, they will separate, or repel each other.)
- Why is it better not to use metals to create static electricity? (Although it is possible for friction on metal objects to result in some static electricity, it does not really work well. This is because the electricity will usually conduct through the metal and not collect on the surface as it does with a material that does not conduct electricity, such as plastic.)
- Describe how Ben Franklin proved that lightning was static electricity. (Ben Franklin proved that lightning was static electricity by flying a kite in a storm and detecting static electricity by seeing the hairs on the kite string stand on end and create a spark on a metal key attached to the kite.)
- How can static electricity damage a computer? (If you touch a computer circuit board, causing a static electricity spark, it can severely damage the circuitry. The sudden surge of electrons can easily destroy the microchips in the computer.)
- Describe what causes a spark. (A spark is the sudden rush of electrons through the air from one conductor to another, heating up the air until it glows white-hot. As the number of electrical charges near the surface of materials increases, the attraction between the positive and negative charges becomes greater. If the attraction is great enough, some electrons will leave their material and fly to the other object. The electrons moving through the air cause it to heat up. As the air gets heated, more and more electrons start jumping over to the other side, causing even more heat to build up until it actually gets white-hot. That is the spark that you see and feel.)
- How is lightning different from a spark? (Lightning works the same way as a spark, except that it happens on a massive scale. Lightning is created when water drops are churning around in a thundercloud. They gather either positive or negative electrical charges, so that soon one cloud may be positive and another cloud may be negative. The electrical pressure that builds up must be extremely high for lightning to start. Lightning can go from cloud to cloud or from the ground to a cloud.)
- What causes thunder? (Thunder is caused by the air expanding and contracting very rapidly.)
- Name several beneficial uses of static electricity. (Uses of static electricity include pollution control, copier machines, and painting.)
- Describe how static electricity can be used to control air pollution. (Factories use static electricity to reduce pollution by giving the smoke an electric charge. When it passes by an electrode of the opposite charge, most of the smoke particles cling to the electrode. This keeps the pollution from going out into the atmosphere.)
After students have completed the webquest, answering the questions in Part 2 of the activity packet, ask them to refine the definition of static electricity and lightning they developed in the Motivation section.
In Part 3, students should explain what changes they made and why they made them. Have students list any evidence they found in the webquest that prompted them to change their definition.
In addition, ask students to explain how static electricity, lightning, and sparks are all related phenomena. Then, draw a diagram illustrating the negative and positive charges that occur in a lightning storm.
The following Internet resources can be used to further explore the topics related to lightning and static electricity:
- Lightning the NOVA Online site, has an Indoor Lightning Activity that provides directions on how to conduct an experiment that involves lightning and sparks.
- Static Electricity discusses static electricity in terms of the potential effects of electrostatic discharge, including preventing electrostatic discharge in electronic manufacturing, materials for electrostatic solutions, and reducing electrostatic discharge nuisance.
- Theater of Electricity at the Boston Museum of Science website has a variety of lightning related topics, including History, Franklin's Kite, Safety Quiz, and Teacher's Resources with experiments.