Today bump cars were made at a 5th grade, 2 first and second TAG classes, a kindergarten, and a 4th grade.
The challenge is to make a car bounce back to the place it starts.
Try one foot, 2 foot, and so on.
The three 5th graders this morning quickly made ones like the version I had made with the Simple Machine sets.
They are doing the Miss Adventure in LEGO CAD and are doing the car (5) so this will work right in.
Perhaps they will get it CADded on Friday.
They did the project out in the hall where there is one foot tiles.
I was interested that they almost immediately could start one foot and return one foot, two foot and return,
. three foot and return with just a few trails, and then go on to do up through 12 feet without having to make any practice pushes.


This piece stayed on pretty well. Just plates did not stay on well.

To get a long distance they had to move back into the room.
The Green C directions gives some ideas on wheel placement.

Next was a very polite 1st and 2nd Grade TAG class that were quiet and well behaved the entire hour.
Again there were one foot tiles on the floor and again they have Simple Machine set in the classroom.
The tried short and long cars.  The group that tried the weight went back to without it.

They had had much experience with 2 plates between to beams and made their cars stable.
One student said the plates were "clamped on" by the beam.  I will have to try to remember that good wording.

Since one of the cars had two bumpers we tried out the bump one end to see the first car move.

Does the wheel need to be kept from turning?

Then I went to another 1st and 2nd Grade TAG class with my Simple Machine sets and
worked with the two grades separately so there were two small groups.  They followed the idea I built and went on to other changes.
That room does not have tile but rather 2 inch wood slats.  They counted out 6, set their cars and made a few trials and could do one foot.
Then they counted out 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24 and could get back to on that line in only a few trials.
And so one to about 5 feet in the time we had.

We had to work out a "wall".

There was a drawer that worked.

One plate between 2 beams does not give the right vertical spacing but 2 plates does.

They checked out the difference between short and long cars.
I brought the cars to Highlawn kindergarten.

  I had 5 quiet students in the hall with one foot tiles again.

From 3 feet - we did it!

Perfect!

They could get the car to return to the 1 ft line after more than three trials, 2 ft after about 3 trials,
3 ft at about  3 or fewer trials.
But when they tried 4 and especially when they tried 5 ft they all over shot.

Putting on little wheels is hard. I wonder how to do this with DUPLO.

I was right about the project being chaos in a large class.
The 4th grade class has 22 kids, usually does robotics, and is currently doing the Mars Mission.
But we took a small break to do the bump car with the team sets and the pieces from the NXT sets.
There were huge differences in the built projects but less than one third actually stayed together after one bump.
The teacher does not mind a little bit of chaos and she got them back on track for putting projects up at the end of the class.

Successful cars


Ok if not pushed too hard


I now have more questions I would like to figure out answers for.
Now I wonder what it is about the force that is needed to go increasing distances.
Is it linear?  How can it be tested? - Perhaps a rubber band launcher like in eLab or a pull back plunger like in Early Simple machines.
Or like the egg flinger I have been doing lately.

Things that helped keep the wild crashing to a minimum - I added a requirement at if in testing a piece came off they could try to "fix it"  but a second crash and they had to go back and take apart their car and redesign.
Each set I own I have put a number on the 1 by 4 tiles.  Those pieces were placed somewhere on the cars to keep track of which set they were from.
Getting kids together for a picture with their car keeps them still for a moment.
I think I will try this at camps after the kids get good at keeping track of pieces and learn about sturdy structures.
Bumper
April 17, 2007
April 18 to 20, 2007