A First Try at Green Screen


The first and second graders at our school have just finished their engineering units. First grade studied how to make high quality play dough by testing out different quantities and proportions of the ingredients to formulate a good recipe. While second grade tried to find out how to build a strong wall by testing different recipes for mortar and different wall designs. Both grades used the Engineering Design Process to guide them through their units:

Photo Credit: kjarrett via Flickr cc

At the end of their units the students reflected on their learning by creating a video. When collaborating with each of these teams, the teachers thought this was a good opportunity for the students to reflect on and summarize their learning throughout the unit. It was also a chance for us to try out the green screen that I had put in my computer lab.

The Preparation

Students:

In first grade, the teachers and I decided not to have the students write down any scripts but to use sentence starters as prompts on a chart instead. This way students could focus on what they remembered as they recorded their reflection rather than just reading off a piece of paper. At the beginning of their Playdough unit, their class teacher created a batch of playdough that was too sticky, grainy and/or watery, this would initiate the entire unit as students then would try to create a better recipe. The prompts to reflect on this experience were:

  • Ask: (What was the problem?)  The problem was…
  • Imagine: (How did you think you could make it better?)  We thought we could make it better by…
  • Plan: (What materials/ingredients did you need?) We needed…
  • Create: (How did you make the playdough? What was the result?) First… next… then…etc. Our first batch was…
  • Improve: (How did you improve your first batch? What did you change?) For our second batch we…Our second batch turned out…

In second grade, the teachers and I thought that students should have more ownership over the video so they prepared their own scripts and wrote out an explanation for what happened for their group at each stage of the Engineering Design Process. The unit begins when the class teacher reads a story to the class about a rabbit that keeps eating the vegetables in a garden. They decide figure out how to build a wall to keep the rabbit out of the garden.

Background Images:

The first grade team decided that since this was everyone’s first time green screening that we would use a common set of background images through all the classes. One image for each stage of the process.

The second grade team again decided that students should have more ownership, they had their students use their iPads to take photographs to document their wall designs throughout the unit. Then when it came time to build the video, students chose 5 images, one to represent each stage. This way, as students talked about what happened through the video, the image behind them would correlate to what they were talking about.

The Set Up

Students came down to the lab two groups at a time, one group would watch in preparatio while the other was filming. We filmed in short clips, one clip for each stage.

 

Piecing Together the Puzzle

Using the app Green Screen by DoInk, students worked in groups to piece together their movie. They had a lot to remember but they really enjoyed learning about the chroma filter and how to adjust it.

Here is a great “how to” video on the app:

In this video the teacher scrolls back through the video to the change backgrounds at different points. BUT it can be difficult to figure out exactly where you want the image to change unless you playback the video. This is why we made individual video clips, one for every image. We added one video and its corresponding background image, then scrolled to the end of the video, added the next video and its corresponding image, till all five sets were pieced together.

The other thing was, the app DOES NOT automatically switch off the chroma filter for images. So, I had to remind students to remember: chroma filter ON for videos, and OFF for images (otherwise anything green in your background image disappears!). 

We have the app on only eight iPads in the school that belong in my lab. We used the same eight devices for all of first grade (7 classes) and second grade (6 classes).

Once the students were done piecing together their videos, we had them export them to YouTube, grab the link and paste it into their individual WordPress blogs so that they could compose a short blog post on the video. All of this was done on iPads.

The Final Product

Here is an example of one first grade video and one second grade video.

You can see that the first graders had a bit more trouble remembering to adjust the chroma filter! Although they found it hilarious when they made themselves invisible. You can see that in some of the clips here they adjusted a little too much and you can kind of see through the kids. Then there’s that clip where they forgot to get rid of the green entirely 😛 Oh well…at least it’s authentic student work!

You’ll notice there are shadows of the curtain to the right side of the video. Lesson learned, we need to pull that curtain tighter so there are less ripples (velcro to the rescue!)

Overall, I think the students did a pretty good job working in small groups to put these videos together themselves. Considering it was also their first time on the app, I think they did well! I would highly recommend this app to anyone thinking of green screening in their classroom. It is super simple and I’m sure some green paper stuck to a wall would work just as well. Enjoy!

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