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Nov 17 / PK

Lesson Six: Holiday Present Maker

We are at the home stretch of the end of the first trimester. With four weeks left it is time for a larger scale project that we can show off what we have learnt. Going with a holiday theme I found a present maker project on that I adapted.

Key New Concepts

This is a complicated project. I am introducing several key and more difficult concepts:

  1. broadcast — have one sprite communicating with another sprite will open up a new level of ability, but this will be a difficult concept for the young scratchers to comprehend, or so I thought
  2. multiple costume — I thought this is a medium difficulty concept. Turns out this concept is actually equally hard, compare to broadcast. I tried using a “different T shirt” metaphor.

Lesson Plan

  1. Show the example project.
  2. Explain the concept of multiple costumes, taking the present aparts — the fact that there are three sprints each with at least three costumes each
  3. Explain the concept of broadcast
  4. Work on drawing the present sprites with costumes — show switching the costumes, with the “next costumes” block
  5. Work on drawing the buttons
  6. Put in the scripts and test out the broacasts


Nov 11 / PK

THE MIT MUSEUM’S 13th Anniversary Friday After Thanksgiving (F.A.T.) Chain Reaction

This event should be of interest to all Scratchers. It is a great event for anyone who love to build things. The event is more than just to watch the Chain Reaction machines, but to participate in may different building and playing activities.

See their website for more details.


Nov 10 / PK

Lesson Five: Cat and Mouse Game

We are getting a lot of mileage out of these movement blocks. The scratchers seems to really enjoy them. So for the “final” week on movement blocks, I showed them a cat chasing the mouse game. By introducing the “point towards” block, I gave them a hint as to now to make something pointing towards, and perhaps chasing after, another sprite that they are controlling.

I was hoping that someone will figure out how to change the simple “point towards” script into a “point towards, then move” script. Only a few of the more advanced scratchers managed to do that with a little bit of suggestion. I was a little disappointed, but it also reinforce the difficulty in understanding the script is a set of direction for the sprite. It is somewhat independent of the scratcher. I have a feeling that is a hard concept to grasp. i.e. the scratcher cannot either put themselves in the shoes of the sprite, or to truly “program” the sprite as an object.

Nov 3 / PK

Lesson Four: Maze Games

Continuing on last week’s “who moved my plane” project, we are going to take the cue from some of the scratchers last week, and build a maze game. It is actually as simple as:

  1. drawing a maze background (how to use the stage), and
  2. doing a collision detection script that check for touching a color — hopefully the color of the maze wall

Most sratchers got it right away. One very cool variation a scratcher did was to move a basketball into a basketball hoop (which is one of the standard background image). Using the same technique, the scratcher test for touching the hoop and said “score” !


I always want to add some extra challenges to the basic project so that the more advanced scratchers have something more to create. I showed them a different version of the maze game, where the main sprite moves constantly, and the keyboard scripts will just change direction. This makes for a more realistic “game” as one does not have to keep pressing the keys to move the sprite. (The mouse in the kitchen version).

The extra challenge part of this week’s project is then to figure out how to do it. Since they know how to make the mouse move constantly already, it is a matter of combining that concept with the keyboard response/action concept.

For the really advanced Scratchers, I also introduced the concept of adding another sprite to chase the mouse, preparing for next week’s lesson.

Oct 27 / PK

Lesson Three: Who Moved My Plane?

This week I want to continue with movement blocks, but finding a way to keep the lesson simple. This new lesson is presented as a challenge. First I show a very simple “when a key pressed, point direction and move 10 steps” script. This way one can “drive” a script (an airplane in this case) in a single direction using a single key.

The challenge is then how to turn that into a game. The first answer is of course to program all four cursor keys so that one can fly the plane in all directions. Then the follow on challenge is to make this basic game more interesting in anyway one wants.

Most scratchers needed a little help to realized one can program other keys by duplicating the basic scripts for other keys. One minor issue is that most scratchers do not understand angles yet. So the “point in direction 90″ block does not make any sense to them. Although the block actually show “up, down, left, right” with the angles as a clue if they click on the angle drop down? Once the angle is set the hint is not visible. At this stage we have helped most scratchers with setting up the script, but I am not sure how many Scratchers actually understand the angles part.

Once a few Scratchers setup the basic “game”, two variations surfaced — I was hoping that this will happen — and several of them figured it out! The first one is – if you put two sprites, two person can drive two different planes around the screen. The second one is, draw something (e.g. a maze) on the stage so that one can have a better “goal” for flying the plane. One or two Scratchers also asked about setting up the project so that when the plane hits the walls of the maze, maybe something should happen…

This week’s lesson was quite successful — partly because the script is short, so we could fit the building part in the one hour time nicely. Also, the driving the plane part is just plain fun.

The class was structured so that I let the Scratchers who did not finish the race from last week catch up with help from myself and Mr. Loefstedt. I don’t want them to fall behind, and also loose their sense of accomplishment. That was a good decisions. At the end everyone finished the racing game from last week.

Since we actually have time left near the end of the session, I got everyone to help shutdown and put away the laptops as well. That saved us a lot of time. Until now we had to spent another 30 minutes or so tearing down and putting the laptops back into the cart, which was a lot of work. I was worried that the younger Scratchers will drop a laptop accidentally when moving them around. Luckily so far we did not have any accident.


move_plane lesson hand out