lesson
A service is not the whole network
1 · Learn
The internet connects networks that exchange data. The web is one service using it, based on linked resources accessed with browsers and servers. Other services can use the internet without being web pages.
A URL identifies a resource location; it does not by itself prove trustworthiness. A secure connection helps protect data in transit but does not guarantee that the site's claims or intentions are safe.
2 · Worked example
I distinguish a browser displaying a page from the underlying connection carrying data. I do not treat a padlock as proof that an unknown seller is honest.
3 · Your turn
Does an encrypted connection prove every statement on a page is true?
Check your answer
No. It concerns transport protection, not the truth or trustworthiness of the content.
4 · Apply your learning
Draw a simplified browser-server exchange and mark where questions about identity, content and transport differ.
Adult guidance and safety
Use an approved private programming or authoring environment and fictional data. Do not install unknown software or enter personal credentials for these exercises. Trace first, then run and test where a suitable tool is available; these text examples do not themselves provide an executable assessment environment.
Open your writing and drawing pad
Write, draw or show your working. Use a mouse, pen or finger. This pad is not a submitted answer.
Not saved to your account. Download your drawing as PNG and your typed notes as TXT before leaving or refreshing. They are separate files. Do not enter private information.
Open a picture saved on this device to draw on it again. Opening replaces the drawing, but Undo can restore it. PNG only, up to 4 MB and 4096 × 4096 pixels. The picture stays in this browser; it is not uploaded. Paper lines in a saved picture become part of that picture.
Clear the drawing? Your typed notes will stay. You can undo this action.
Your pad is empty.
Open a UTF-8 TXT file from this device, up to 40 KB and 10,000 characters. It stays in this browser. Opening can be undone until you type again. Downloads keep a new copy; they do not change the file you opened.
Replace the notes on this page with the opened file? Download the current notes first if you want to keep them.
Typed notes are not submitted answers.
Check a calculation · Year 5 onward
Use this only when your teacher or adult allows a calculator for the task. Show your thinking first. It does not replace mental or written arithmetic and does not mark your lesson answer.
Powers, roots and trigonometry · Year 7 onward
Use only when the task allows a calculator. Choose one operation at a time and record your working. Trigonometry here always uses degrees (DEG), not radians. Inverse sine, cosine and tangent return an angle, not a reciprocal. Keep exact fractions and π in answers when requested.
Approximate numerical results use up to 12 significant digits. Inverse sine returns −90° to 90°, inverse cosine 0° to 180°, and inverse tangent −90° to 90°; these are principal values, not every possible solution of a trigonometric equation.
Practice this lesson
Lesson resources
Browse the available practice activities and worksheets for this lesson.
Your progress