Thursday, April 1, 2010

Scratch - Take Three

I continue to enjoy working with student using Scratch. This year, I upgraded all the computers to the newest version 1.4. I will begin working with grades five through eight after Easter break. I started with sixth grade this past week, and found that we hadn't used it last year. I'm starting over with the sixth in a different way.

Laying the Foundation - Lesson One
I introduced the program as I usually do: we gave the cat a move 10 steps block and double clicked the block. Next we added a goto x: 0 y: 0 block to the screen and double clicked it to bring the cat back to the center of the screen. We added the when green flag is clicked icon to the move 10 steps block and saw its effect and added a turn 15 degrees right. I asked them what forever means and showed them how to include a forever block with the commands. Then they took some time to play with the two numbers seeing what happened if they made the number larger and smaller. They double clicked the goto x: 0 y: 0 block when they lost their cat.

The Sprites and the Stage
We brought on another sprite of their choice with the Choose new sprite from file option. This year, I made sure to tell the students *not* to select a sprite with a script attached. This kept me out of the problems I ran into in the past with unexpected scripts. They tested out the Costumes tab above the script area and used the Edit button to customize their character. The students have no end of fun customizing. I kept the time very short - just two minutes - so that we could test out a couple of extra options.

I had the next sprite react to a click. Sprite two was given a when sprite2 is clicked control block with a look of think Hmm... for 2 seconds. While they worked on those commands, I explained how to create a stage of their choice. They are very familiar with drawing tools from their work in Kid Pix and Gimp, so I simply had them click on the stage. I pointed out that the Costume tab changes to a Backgrounds tab and they went to work. Immediately, they wanted to test importing a stage and enjoyed looking at the possibilities.

One of the students found the point towards mouse-po
inter motion block, so we did that as a group as well.

Continuing the Process - Lesson Two
In our second 42 minute period, I wanted to teach the students some commands that would allow the sprites to interact. We started a new file with the cat.

This time, we started with the concept of repeating a certain number of times versus doing something forever. I asked them what they thought would happen if we told the computer that when the green flag was clicked the program would have the cat move to x:0 y:0 10 times. We teste
d their opinion and saw that the cat didn't appear to do anything, but it was told to move to 0,0 ten times.

I asked a few students to pick a number from 0 to 100. We discussed that I had no idea what they would say. They could have picked the same number or different ones, but it would be from 0 to 100.

We dragged a pick random 0 to 10 operator blo
ck into the x slot of the goto command. We tried to predict what would happen and then the students tested it. The cat randomly moves left and right. I asked them to follow that by placing a random operator in the y slot of the goto command. Now the cat jumped all over the stage. I wanted the students to understand that they could slow down the operation, so we added a wait 1 secs control block beneath the goto block.

Copying and Adjusting Commands
Next, I wanted the cat to be chased, so we added another sprite and dragged our cat's script to the second sprite. A few students needed help recognizing the light white line around the second sprite that signaled the script would be copied.

I wanted the students to become aware of the sensing feature. I asked Student A if they were sitting next to Student B and they said yes. I asked Student C on the other side of the room if they were sitting next to Student B. They said no. I told student A that if they were sitting next to Student B to please clap. I did the same for Student C. We moved on to the if touching block.

We added an if block to the repeat loop. I pointed out the hexagon shape in the if block. We moved to the sensing commands, dragged in a touching block, and set it to Sprite2. We added a command from the previous class to think Hmm for 2 seconds. If Sprite1 sensed Sprite2, we would see the message.

Closing the Lesson and Testing Sprite Changes
I wanted to make another very visual change to the sprites if they touched. For this, we used Sprite2. We added an if block with a touching option just as we did to the cat, but instead of using the think block, we went to the Looks commands and dragged in a change color effect by 25. We tested the new option and found that every time Sprite2 sensed Sprite one, the color changed by 25. If we wanted Sprite2 to go back to the original color, we would have to tell it to clear the graphic effect. When those commands are placed one after another, the change happens too fast for us to recognize it, so we needed a wait 1 secs block between the two commands.

They finished the lesson by testing the other change options: fisheye, whirl, pixelate, mosaic, brightness, and ghost. Some students tried random numbers in the effect by 25 portion of the block. Many customized the stage and sprites.

Overall, I felt that this was an effective way start to Scratch with the sixth graders. A number of them told me that they had already downloaded the program at home.

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