Lesson: Crawling the Web (6-8)

Introduce

ASK: What search sites have you used? (Students may name Google, Yahoo, or Bing, among others.)

ASK: What do you like about each site? What made you decide to use it? Sample responses:

• All my friends use it
• I like the way it looks
• I usually get the information I need when I use it
• I didn’t know I had a choice
• Results are easy to read

Record the student responses so you can refer to them at the end of the lesson.

DISCUSS with students that search sites have different benefits and drawbacks, so it is important for them to make informed decisions about which ones to use depending on the situation. Explain that they will now look at some search sites to find out how each one works and how they are different from one another.

Teach 1: Three-Way Search

DISTRIBUTE the Three-Way Search Student Handout.

GUIDE students through “Do you know how a SEARCH ENGINE works?” Review the three programs a search engine uses to collect information from webpages, index the information, and match the webpages to their keyword searches. Though optional, you are encouraged to model the three types of online searches for the class.
Conduct searches with the sites suggested below and show students what you find.

REVIEW the Key Vocabulary with students.

ASK: Why do you think the first program is called a spider? (Because it crawls around the Web, exploring webpages and their links and collecting information.)

ASK: Can you think of another good name for it? (Students may suggest a snake, which also crawls, or a dog, which fetches things.)

ASK: Why do you think the spider has to keep crawling the Web, over and over again? (Students should understand that information on the Web is always growing and changing, and the spider needs to constantly check for updates.)

READ through “Do you know how a DIRECTORY works?” with students. Point out that directory editors, like spiders, are always looking for new information on the Web. However, they can’t look at quite so much as spiders, or do it so quickly. Explain to students that editors sometimes add new subject categories and sites based on the number of information  requests users make for certain subjects.

Conduct a search for the class in either or both of these kid-friendly online search engines: Factmonster and Quintura. You could search the term “search engine,” or something else of interest to the class. Project the results for class discussion.

ASK: How is the information in a directory different from the information retrieved by a search engine? (Students should understand that people, not computer programs, select the sites that are included in directories.)

ASK: What are some of the advantages and disadvantages of using a directory instead of a search engine? Sample responses:

• Advantage: People carefully choose the sites in a directory, so they might be better sites
• Disadvantage: The editors who create directories can’t index everything on the website, so they might miss some relevant sites

Conduct a search for the class in either or both of these kid-friendly online directories: Yahoo (kid directory) and ipl2. You could search the term “directories,” or something else of interest to the class. Project the results for class discussion.

REVIEW “Do you know how a META-SEARCH ENGINE works?” with students. To help them understand the difference between a “narrow” topic and a broader one, provide them with the following examples of keywords they might use for each type:

Broad

• Abraham Lincoln
• World Cup

Narrow

• Abraham Lincoln Abraham Lincoln 1860 Cooper Union Speech
• World Cup 2010 World Cup United States-England match

Tell students that they will have a chance to investigate some search sites on their own.  Conduct a search for the class in either or both of these kid-friendly online meta-search engines: Dogpile and MetaCrawler. You could search the term “meta-search engine,” or something else of interest to the class. Project the results for class discussion.

Teach 2:Compare Your Hits

ARRANGE students into groups of three or four and give each group one copy of the Compare Your HitsStudent Handout.

ASSIGN to each group one of the search sites mentioned on the Three-Way Search Student Handout. To ensure that different groups sample each different type of search engine, you may wish to assign the following sites in order. The number of sites used will vary depending on the size of your class, but make sure to assign at least the first three.

EXPLAIN to students that they will be looking at some of the features of their assigned sites and answering questions about them. They will try out two searches, see what results or “hits” they get, and then compare and contrast the results from different sites.

1. Google (search engine)
2. Yahoo Directory (directory)
3. Dogpile (meta-search engine)
4. Ask (search engine)
5. Dmoz (directory)
6. MetaCrawler (meta-search engine)
7. Quintura for Kids (search engine)
8. Yahoo Directory for Kids (directory)

Have each group of students follow these steps, allowing a total of 10 to 15 minutes:

READ through the Compare Your Hits Student Handout
 

DRAW their site’s logo, or print it out and cut and paste it onto their handouts

EXPLORE their assigned sites and answer the first two questions on the handout. (Students can return to the Three-Way Search Handout for help if they are not sure which type of site they have.)

SEARCH for the keywords on their search sites

PRINT OUT or copy the main items on the first page of search results

INVITE students to post their handouts, with results below them, on a bulletin board, blackboard, or wall.
Give students 5 to 10 minutes to look at the results posted by other groups.

DISCUSS the similarities and differences among the results from each search site. Ask students to identify one
thing they liked about the site they investigated, and one thing they prefer about the results from another site
visited by their classmates.

Wrap Up & Assess

You can use these questions to assess your students’ understanding of the lesson objectives.

ASK: How do search engines and directories differ? (Search engines are indexed by computer programs, and directories are indexed by people. Search engines usually have many more sites indexed than do directories.)

ASK: What was one feature you liked about the site you visited? (Have students refer to the data they recorded on the Compare Your Hits Student Handout.)

ASK: Why is it a good idea to try more than one search site? (Because no one search site covers the entire Web. Also, search sites offer different search options.)

REVISIT the questions you asked students in the lesson introduction. (What search sites have you used? What do you like about each site? What made you decide to use it?) Ask them to respond to the same questions again.

REFLECT on the value of trying the same search on the three different types of sites. Students should begin to grasp that different types of sites – and different sites within each type – may be more effective for different kinds of searches. They should understand that no one site, no matter how popular, offers the “definitive” search results. They can and should experiment with them to learn how to make informed choices about which search sites to use.

Extension & Homework

EXTENSION ACTIVITY
Students practice being directory “editors.” Remind students that one of the jobs of a directory editor is to place websites in different categories, depending on the information they contain. Invite students to choose a simple keyword to submit to a search engine that relates to a topic they are learning about in your class. Have them click through to each of the first five search returns they believe are high-quality sites. Ask students to assign each site to one of the subject categories from a popular directory, such as Yahoo Directory.

HOMEWORK
Have students make a three-part “blueprint” showing the three steps a search engine uses to collect information from the Web, index information, and match the information to keywords. The three parts of the blueprint should show: (1) an example of a word that they are searching, (2) what happens when that word is searched, and (3) the results or “hits” they get. When they are finished, they should describe to their parents how the three different types of search engines work. They should also explain how searches are performed in the blueprint that they drew.