Exercises: Reliable sources

From this list of elements on a web page, state which ones help assess its reliability and which do not, justifying each response: known authorship, publication date, number of "likes", attractive design, cited sources, spelling mistakes.

For a project on the solar system, you have found these sources: a specialised encyclopaedia, an anonymous forum, a science museum website, a social media video with no known author, and an article in a scientific journal. Order them from most to least reliable and justify the order chosen.

To keep only the sources that are trustworthy, you can pass the results through a series of filters, as shown in the diagram, but one of the filters is covered up.

Propose the missing filtering question in the covered step and explain why it is important to apply it before using a source in a project.

An article shows two dates: "published on 3 March 2019" and "updated on 12 January 2026". Explain the difference between the two and which one you would check to decide if the information is up to date, giving an example of a topic where updates are crucial.

Many websites have an "About us" or "About" section. Explain three things you would check in that section before trusting the web page, and what you would suspect if that section did not exist or were empty.

Classify these four headlines as "fact" or "opinion" and justify each decision: (a) "The Ebro River is 930 kilometres long", (b) "The Ebro is the most beautiful river in Spain", (c) "Yesterday it rained 23 litres per square metre in Zaragoza", (d) "Cities by the river are the best places to live".

Explain the difference between a primary source and a secondary source using this scenario: for a project about life in the 1960s, your grandmother tells you what her school was like, and you also read a history book that summarises that era.

Write down three red flags that would make you doubt a web page at first glance (for example, a headline written to cause fear or shock), and give a made-up example of each.

Two web pages contradict each other regarding the height of Mount Teide: one says $3715\ \text{m}$ and the other says $3718\ \text{m}$. Explain step by step how you would decide which figure to use in your project, and what might cause two sources to give different values.

You find an article written in 2012 titled "Mobiles of the future". Explain whether the date of publication affects its reliability and give two examples of topics where the date is crucial and one example of a topic where it hardly matters.

On a collaborative online encyclopaedia, almost anyone can edit articles. Explain the advantages and risks of this, and describe how you would use it correctly as a starting point for a project without relying on it completely.

A basketball match ends in controversy in the final minute. A newspaper from one city runs the headline "Scandalous theft in the final second", while the rival city's newspaper headlines "Deserved victory in a thrilling finish". Explain what source bias is, how it is detected in this case, and how you would write a neutral summary of the match.

A photo of an impressive flash flood is circulating on social media, presented as "from this week in your town", but the image is actually from another country and six years ago. Explain what a reverse image search is, how it would help you uncover the deception, and what other two checks you would carry out.

Web addresses end in domain extensions such as .edu, .gov, .org, or .com. Explain what usually lies behind each of these domain extensions and reason why the domain extension alone does not guarantee that the information is reliable, giving an example for each case.

Cross-checking information does not mean finding it repeated on three websites, because those three websites may have copied it from the same incorrect source. Explain what it means for sources to be "independent", and describe how you would verify a statistic about the population of your province using three genuinely independent sources.

An article states: "80% of teenagers use AI to do their homework", without indicating where that figure comes from. Describe how you would try to track down the original survey or study and what questions you would ask about that study (how many people were surveyed, who they were, when) before believing it.

A nutrition blog enthusiastically recommends a "miracle" smoothie, and all its links lead to the online store selling it. Analyse the reliability of that page taking into account authorship, potential financial interests, and the cited sources, and propose where you would cross-check the information.

Design a checklist of six to eight questions to evaluate any internet source. Then, make up a description of a specific web page (topic, author, date, appearance, adverts) and apply your checklist to it, stating your conclusion.

A false statement appears copied, almost word for word, across twenty different websites. Explain why the fact that an idea is repeated in many places does not guarantee that it is true, and describe how you would attempt to track down the original source of the statement.

You are looking for information for a project on urban mobility and you find an article titled "Why this electric scooter is the safest on the market", signed by "Editorial Staff" and with a small tag at the end stating "Sponsored content by EcoScooters". The text only highlights advantages of the product and includes a link with a discount code to their store. Justify why this article lacks neutrality compared to an independent journalistic report, explain what biases it presents, and design a search strategy (with specific keywords, operators, or types of sources) to find the weak points or actual failures of that model.

The school's digital magazine wants to publish news about an alleged closure of the local library. Design the verification protocol that the editorial team should follow before publishing it: which sources to consult, whom to ask directly, and what to do if the accounts do not match.

A headline reads: "Ice cream consumption causes drownings: both rise together every summer". Explain the difference between correlation and causation, what third factor explains this case, and write a correct headline that informs without misleading.

On the high school's social network, a ten-second video goes viral where the mayor appears to announce that classes are suspended tomorrow due to an extreme cold wave. Looking closely, the voice sounds metallic and the outline of the mouth shows a blurry flicker that does not match the pronunciation of certain words. Technically justify why these clues point to a "deepfake", predict what consequences sharing it without verifying would have, and design a three-step protocol that students should follow to verify the news before staying home.

The same content creator can be a good source for some topics and a poor one for others: a famous athlete speaking about training versus vaccines. Establish a criterion to decide when someone's personal experience is sufficient as a source and when it is necessary to consult specialists, and apply it to two further examples.