You have already practised spotting when a picture, clip or recording has been changed. Today's question is harder. Can we still tell when something was never filmed, photographed or recorded in the real world at all?

You will learn about deepfakes and synthetic media, which means pictures, sound or video made by a computer. Then the class will vote on items as "real", "likely synthetic" or "cannot tell", and talk about what this means for news, evidence and trust.

Synthetic media is pictures, sound or video made fully or partly by a computer, not recorded from real life. A deepfake is media made or changed by AI so that a real person seems to say or do something they never did.

There are three answers you can choose from:

• Real: recorded from real life, with small natural flaws and a source you can check.
• Likely synthetic: strong signs that a computer made or changed it.
• Cannot tell: not enough evidence in what you can see or hear.

A sharp, clear picture does not prove something is real. Sometimes "cannot tell" is the right answer.

This is a class vote challenge. Start with Item 1 in the activity below. Look at it closely with a partner and talk about what you notice. Then the class agrees on one answer, "real", "likely synthetic" or "cannot tell", so be ready to say why. After the class has decided, the reasoning is shown. The reasons matter more than a score.

In the next step, everyone votes on every item on their own device. Item 1 comes first again so that everyone gets their own vote. Be ready to say which detail helped you most. If you chose "cannot tell", be ready to say why there was not enough evidence to decide.

Now everyone votes on every item on their own device. Round 1 is the item you just worked through together.

• Read the item and choose your answer.
• When the reasoning comes up, compare it with the reason you gave.