When a printable and an interactive activity belong together

When pupils move a slider and watch the result, you can see what they’ve tried. A few questions on paper can help you follow their thinking: what did they expect, what happened, and why?

If the activity already saves their predictions and explanations, you can use those for the same discussion.

Start with one question

Choose the question you want to explore with your class. In the Photosynthesis Lab below, you could ask: “What happens when we increase the light but leave carbon dioxide and water as they are?”

Pupils can try the change on screen. On paper, they have somewhere to explain what they expect before they try it, then make sense of the result afterwards.

For this comparison, a few questions will do. Leave room for pupils’ own words, as PhET’s guidance on activity sheets suggests.

Try it with the Photosynthesis Lab

Have a go with the Lab below. Set light to 50, carbon dioxide to 50 and water to 80. You’ll see 30 beside the label “relative model index”.

Before increasing light to 80, give pupils a moment to decide what they expect. Ask them to write a prediction and a reason. Then move the light slider, leaving the other two settings as they are, and look at the result together.

Using a small screen? Scroll sideways inside the activity to reach the sliders.

Here are three questions you could put on a sheet, with the starting settings at the top.

Three questions to try
Start with light at 50, carbon dioxide at 50 and water at 80. The score is 30.
Increase light to 80, keeping carbon dioxide and water at their starting settings.

When to ask	Question for pupils
Before moving the slider	Will the number go up, go down or stay the same? What makes you think that?
After the change	What number can you see now?
Talk it through	How do the light, carbon dioxide and water settings explain what happened?

Teacher notes: what happens in this example?

The score stays at 30. The model uses the lowest slider setting to calculate it. Light and carbon dioxide both begin at 50. Raising light to 80 still leaves carbon dioxide at 50, so the score doesn’t rise.

This is a simplified model. Changes in temperature are left out, and the animated bubbles aren’t measurements.

Talk through the answers

The explanation is where you can pick up the conversation. A pupil might write “30” accurately but still be unsure why the number stayed the same.

You could ask: “Let’s look at the settings again. Which one is lowest now?” Give pupils a chance to reconsider their first idea and add to their answer. PhET’s facilitation guidance describes using written responses to check pupils’ ideas.

Some pupils may find it easier to explain aloud or mark up a picture of the settings. You can note their explanation and return to it during the discussion.

Get it ready for your class

Before the lesson, try the activity yourself and answer the questions. Use words your pupils know, and leave enough space for them to give a reason.

Check the activity on the device you’ll use. If you’re demonstrating it on a shared screen, pause for everyone’s prediction before moving the slider. If pupils are working in pairs, let both share a prediction before one takes the controls.