Last week I finally got round doing something I had wanted to do with my Yr11 classes for a long time. We acted a Displacement – Time graph. This might not sound amazing to you and I have done a similar activity in the past, but this time the difference was that my learners could actually check their outcomes very quickly and without having to guess if their movements reflected the D-T graph faithfully, as they could use what I think is one of the best iPhone/iPad App for Physics, the Vernier Video Physics app!

Indeed, we could have used cameras to record the videos and upload the videos on our laptops to use with Tracker, but the versatility of an iPad and the simplicity of the Vernier Video Physics app made things very easy and intuitive.

So, what’s this activity about? Well, the learners split into groups of 3-4 and analyse the graph below.

Then, they organise themselves to act the graph. So, one person will walk along a straight line to mimic the graph, whilst the others in the group could help signposting important parts of the graph, as well as keeping the time.

You can see how the Vernier Video Physics app renders the video after tracking the object in each photogram. The images at the end are the displacement and velocity analysis after the tracking has been completed!

What do you think? Is this group representing the graph well?

  1. Mike says:

    They certainly seem to have a good understanding of motion graphs Alessio

    Two questions though
    Why not use ‘displacement’
    Does it beat using an ultrasound detector with a data logger?

    • Alessio Bernardelli says:

      Hi Mike,
      Using an ultrasound sensor and data logger is a really effective way of doing this and it has the advantage that the learners can see the graph plotting as they move, which would reinforce many aspects of D-T graphs, but I think the advantage of using a video tracking app like Video Physics is that the learners need to really think in abstract terms when they Plan and act the graph, as they can only imagine in their heads what the graph is going to look like when they will track it. Also, I think it is quite useful for them to see the dots spreading out when they move faster, etc. it makes it very visual and memorable I believe.
      Thanks for your feedback,

    • Alessio Bernardelli says:

      Hi again Mike,
      Yes, you’re right! It should be displacement on the y-axis! Thanks for pointing it out!

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