Comets
Teacher Page: Lesson Plan

 

Index:

Goal/Purpose
Desired Learning Outcomes
Prerequisites
New Vocabulary
General Misconceptions
Preparation Time
Execution Time by Module
Physical Layout of Room
Materials
Procedure / Directions
Evaluation / Assessment
Solutions
Follow-up Activities / Interdisciplinary Connections
One-Computer Classroom
Classrooms without Computers
Home Schooler

 

Goal/Purpose:

The purpose of this lesson is for students to explore the nature and composition of a comet. The student will select ingredients to create a comet. They will learn to identify ingredients responsible for a comet nucleus, and how changes in the nucleus when the comet approaches the Sun causes two different kinds of tails to form. Students can explore some facts, myths, and legends linked to the appearance of comets throughout history.

 

Desired Learning Outcomes:

  1. Identify the parts that make up a comet.
  2. Describe what happens to a comet as it travels closer to the Sun.
  3. Identify the different types of comet tails.
  4. Read about facts, legends and myths related to comets.

 

Prerequisites:

Before attempting to complete this lesson, the student should:

 

New Vocabulary:

Ammonia (NH3)—
A chemical compound consisting of four atoms: one of nitrogen and three of hydrogen. At standard temperature and pressure on Earth, ammonia is a gas. In the cold vacuum of space, it is a solid; when hit by sunlight, it becomes a gas. Ammonia has been observed in comet comas.

Noncrystalline carbon (C)—
A solid state of carbon in which the atoms are arranged at random, having no crystal or layer structure. On Earth, charcoal is a type of noncrystalline carbon. Very small particles similar to noncrystalline carbon atoms have been observed in comet comas and tails.

Carbon Dioxide (CO2)—
A chemical compound consisting of three atoms: one of carbon and two of oxygen. At standard temperature and pressure on Earth, carbon dioxide is a gas. In the cold vacuum of space it is a solid; when hit by sunlight, it becomes a gas. Carbon dioxide has been observed in comet comas and tails.

Coma —
The cloud that forms around a comet's nucleus. This cloud is made by solar wind striking the surface of the nucleus, causing a mixture of gas and dust to form around it.

Diamond (C)—
A state of carbon in which the atoms are arranged in crystals. Diamond is a solid on Earth and in space. It is believed to be a part of a comet's nucleus. Microscopic amounts of this substance have been found in small meteorites that have landed on Earth —some of which may have come from comets.

Dust Tail—
This type of comet tail forms when the solar wind separates dust from the coma, pushing it outward away from the Sun in a slightly curved path.

Formaldehyde (HCHO)—
A chemical compound consisting of four atoms: two of hydrogen, one of carbon, and one of oxygen. At standard temperature and pressure on Earth, formaldehyde is a liquid. In the cold vacuum of space, it is a solid; when hit by sunlight, it becomes a gas. Formaldehyde has been observed in comet comas.

Gas-Ion Tail—
This type of comet tail forms when the solar wind separates gases from the coma, pushing them outward away from the Sun in a straight path.

Graphite (C)—
A state of carbon in which the atoms are arranged in layers, graphite is a solid on Earth and in space. Very small particles similar to graphite, like carbon atoms, have been observed in comet comas and tails.

Methane (CH4)—
A chemical compound consisting of five atoms: one of carbon and four of hydrogen. At standard temperature and pressure on Earth, methane is a gas. In the cold vacuum of space, methane is a solid; when hit by sunlight, it becomes a gas. Methane has been observed in comet comas.

Nucleus of a Comet—
The solid rocky part of a comet.

Sodium (Na)—
A chemical element whose atoms are arranged in crystals. Sodium is a solid on Earth. In the cold vacuum of space, it is also a solid, probably in the form of a chemical compound. When hit by sunlight, sodium becomes a gas. Sodium has been observed in comet tails.

Silicon Dioxide (SiO2)—
A chemical compound consisting of three atoms: one of silicon and two of oxygen. Silicone dioxide is a solid on Earth and in space. It is found in rocks, and is the primary ingredient of sand on Earth. In space, it is very often found as dust. Silicon dioxide has been observed in comet comas and tails.

Solar Wind—
A stream of charged particles ejected from the surface of a star.

Water (H2O)—
A chemical compound consisting of three atoms: two of hydrogen and one of oxygen. In the cold vacuum of space, water is a solid; when hit by sunlight, it becomes a gas. Water, which is a comet's most abundant compound, has been observed in comet comas.

Meteor—
The flash of light that we see in the night sky caused by the friction of a meteoroid passing through the atmosphere.

Meteoroid—
An interplanetary chunk of matter that is smaller than a kilometer in diameter and most frequently measured in millimeters.

Meteorite—
Any part of a meteoroid that that survives its fall through the atmosphere and lands on the Earth.

Asteroid—
A small solar system object composed mostly of rock. Many of these objects orbit the sun between Mars and Jupiter. Their size can range anywhere from 10 meters in diameter to less than 1000 kilometers.

Comet—
A small solar system object consisting of ice and other compounds that form a coma and sometimes a visible tail whenever they orbit close to the Sun.

 

General Misconceptions:

Students may not realize that comets are a part of the Solar System. They may think that all comets look the same and are not that much different than other small interplanetary objects such as asteroids and meteoroids.

 

Preparation Time:

  1. Provide time to download computer software to support the lesson.
  2. Allow time to preview all of the activities and to read the science background pages.

 

Execution Time by Module:

The amount of time needed to complete any of these modules will vary depending on the length of available teaching time and the ratio of computers to students in the class. One possible way to jump-start your lesson and eliminate the trial-and-error that is sometimes needed to become familiar with a new lesson is to have the students do just one activity or a part of a module. Use an overhead, an LCD, or a TV monitor to project the lesson to the class. The following are estimated times:

 

Physical Layout of Room:

Teachers may decide whether students will work in small groups of two or three, or individually. To maximize learning, no more than three students should share a computer. Adaptations can be made to accommodate classrooms having a single computer with Internet access. These might include using an overhead projector with an LCD to project the computer image onto a screen or hooking up a computer to a television monitor.

You can also do Comets off line. Different software programs provide off-line access to the Internet. Their programs allow you to save Web pages to your local hard drive. Using your Web browser, you can open the Web pages locally and experience the lesson as if you were on the Internet. Using this option, however, will deny students access to the rest of the pages available on the World Wide Web.

 

Materials:

This lesson requires a computer with a color monitor and Internet connection. The Web browser must be capable of running Netscape's Navigator 3.0 (or better) or Internet Explorer 4.0 (or better). For additional information, read the Computer Needs section.

 

Procedure / Directions:

This is a self-directed interactive computer activity. Students may work independently or in small groups to complete each activity.

Suggested Engagement Activities:

  1. Use images of comets, which can be found at the Space Telescope Science Institute's Web site, http://www.stsci.edu, and project them on a screen or television monitor. In a class discussion, ask students to describe what they already know about comets and planets and what they can learn from the images.
  2. Organize an informal debate or discussion on the topic, Comet Collisions with Earth: Fact or Myth?

Step-by-step Instructions:

Comets consists of three activities, "Make a Comet," "Comet Tails," and "Facts, Myths, and Legends." It is suggested that students do the activity "Make a Comet" first. The information provided in the activity teaches some basic information about the structure of a comet and identifies two different kinds of comet tails. "Comet Tails" is an assessment activity that is based upon what the students observed about comet tails in "Make A Comet."

Make a Comet asks students to create their own comet by selecting from a choice of possible ingredients. The comet will include a nucleus, a coma, and either a dust tail, a gas-ion tail or a combination of dust tail and gas-ion tail(s). Students should draw the conclusion that the comet's ingredients affect the way it looks. After making their comet, students can watch their comet go on an imaginary trip around the Sun. Three things can be observed: (1) The comet moves faster as it gets closer to the Sun; (2) The comet's tail always points away from the Sun; (3) The comet's tail becomes longer as the comet gets closer to the Sun, and eventually disappears as it moves farther away from the Sun.

Comet Tails shows real images of comets and challenges students to identify the different types of tails. Clues are provided if students need extra help recalling what they learned about comet tails in the "Make a Comet" activity.

Facts, Myths, and Legends is a reading activity that offers interesting facts about famous comets. Also included are myths and legends linked to the appearance of comets.

Evaluation / Assessment:

The activity Comet Tails is an assessment activity that is based upon what the students observed about comets in the "Make A Comet" activity. It challenges students to observe images of different comets and asks them to identify what type of tail or tails the comets are showing.

Solutions:

Before beginning the activity "Make A Comet," students should click on the "Help" button, which will provide information on how to operate the comet - making mixer machine. When the proper combination of ingredients has been put together, students will see what their comet looks like and will learn some facts about it. There are six possible types of comets that can be made using the mixer machine. They include: (1) a comet with no visible tail (2) a comet with a dust tail (3) a comet with one ionized gas tail (4) a comet with two ionized gas tails (5) a comet with a dust tail and one ionized gas tail and (6) a comet with a dust tail and two ionized gas tails.

Solutions can be found for "Comet Tails" within the activity. Before starting students should read the directions called "Identify Comets." Based upon what students have observed in "Make A Comet," they now observe images of actual comets and are asked to select one of five possible comet tail choices. If they are not certain about which choice to make, clues are provided by clicking on a magnifying glass. When the choice is correct, students are rewarded with some additional information about the comet.

 

Follow-up Activities / Interdisciplinary Connections:

You can find other images of comets and planets at the Space Telescope Science Institute. These images could be shown directly to the class using an overhead projector, an LCD, or a TV monitor. Paper-copy versions of images taken by the Hubble Space Telescope and other NASA missions also are available at your closest NASA Educator Resource Center.

Connections to other disciplines can be used to broaden classroom discussion of Comets.

Biology: Some scientists think that a comet or asteroid collided with the Earth and killed the dinosaurs millions of years ago. Research and discuss this idea.

English: Ask students to write a poem or a story about a comet.

Social Studies: Ask students to research the relevance of comets in different cultures. Create a hypothetical situation in which a comet collides with our planet. What steps would the survivors have to take to live in a post- collision world?

 

One-Computer Classroom:

It is recommended that teachers project the images from the computer onto a classroom screen using an overhead, LCD or television screen. To facilitate a more organized and predictable large-group presentation and avoid last-minute glitches, consider bookmarking the lesson (such as one of the pages you wish to use) and downloading it onto your hard disk. This will eliminate the inconvenience of unexpectedly going off the Internet.

 

Classrooms without Computers:

Here are some suggestions:

  1. If you have access to a computer with World Wide Web capabilities at home or in the school library, you may print selected parts of the lesson as paper copies or transparencies.
  2. If your school has one or more computers located outside your classroom, students may experience the lesson individually or in small groups as a learning station.
  3. Some students might have computers at home with access to the Internet. If that's the case, you might consider assigning sections of the Comets activity as homework or extra credit.
  4. NASA offers FREE comet and Solar System-related lithographs and posters, which are available at your closest NASA Educator Resource Center. They can be used as teaching tools in the classroom.

Home Schooler:

This lesson is easily followed without additional teacher support if the prerequisites are met. Parents can preview the lesson and examine the teacher pages ahead of time. A wealth of information can be found at Hubblesite, the Hubble Space Telescope's website at the Space Telescope Science Institute. Here you can find background information on the telescope, pictures and news releases of past and present stories, education activities, and other science resources.

More information for the home-schooled can be found at:

 

Send your comments related to this page to: amazing-space@stsci.edu