Search technologies | Year 5 Computing PDF Download

Search Technologies

• Definition of a Search Engine: A search engine is a computer program that locates webpages on the Internet.
• Function of a Search Engine: It is a tool that enables users to access and retrieve information from websites and other online resources.
• Importance of Search Engines: Search engines are heavily utilized globally, with billions of searches conducted daily to gather information from the web.

Search Engine Indexing

• When we enter keywords, a search engine looks through its index for webpages containing relevant information.
• This index is created by web crawlers.
• These are automated programs that record key information from webpages.
• A web crawler records the webpage's URL, keywords, and any links it has to other webpages.
• All of this information is stored in the search engine's index.
• Web crawlers are constantly visiting webpages, as new content is added to the web all the time.
• This ensures that the search engine is using an up-to-date index.
• Some webpages are not visited by web crawlers.
• This is because the owners of the websites have requested that these pages are not placed in a search engine's index.

Returning results

• Search engines also rank the pages they find for you. They use an algorithm to identify the most useful pages and place these at the top of the list. The algorithms use ranking signals to determine which webpages will be most useful to you.
  These signals include:
  • The number of links from other webpages to this webpage
  • The number of times the keywords appear in the text on the page (although too often is a bad thing)
  • The use of the keywords in the URL
  • How often the webpage is updated
• You might find it useful to think of this ranking as giving each page a score based on its performance in the ranking signals above. The higher the webpage's score, the higher it is ranked.
• Have you ever seen the letters "AD" next to one of the results from a search engine? This means it is an advert. The company has paid the search engine to place their result at the top of the list. The search engine shows "AD" next to the result to let you know this.

Other Ways of Utilizing Search Engines

People have been typing keywords into search bars for over twenty years. Now, there are other ways to use search engines:

• Voice Search: Some wireless devices allow us to use our voice to ask questions and use search engines to find answers.
• Image Search: We can use a smartphone camera to provide a search engine with an image, which it can then:
  • Identify the image
  • Find similar images
  • Translate text in the image into different languages
  • Locate shops that sell the item in the image
• Song Identification: You can even use a search engine to identify a song that is playing on your radio.