Fun with Roller Coasters

We had planned to have a fun science/engineering day back in December just before winter break with the 3rd graders.  But a bug struck our family and had us down and out for the two weeks before break, so I had to cancel this session.  I spoke with the teachers and we decided to go ahead and use this one out of sequence for our session this week.  What a great time the kids had!  They all proclaimed that this was their favorite activity we have ever done (which is saying a lot since I have been doing science with these kids since kindergarten!).  I used a writeup from teachengineering.org called Building Roller Coasters.  The grade level rating on this exercise is grade 7, but the third graders did great with this activity.  I have also seen something similar written up in Exploratopia (pg. 155).  Both activities use pipe insulation cut in half.  Each team of three was given a cup with a glass and a steel marble, a 6 foot piece of pipe insulation, 12 inches of masking tape, a pencil, and a scoring table.

Roller Coaster Scoring

Roller Coaster Features	Points	Your Design
Height	1 point / 12 inches
90 degree turn	1
180 degree turn	2
270 degree turn	3
Loop	3
Corkscrew	4
Each marble in cup	3
TOTAL POINTS

We talked a bit about potential and kinetic energy, asking the students if they could explain what each meant, and we also talked about acceleration and deceleration.  We then let them go build.  The most points awarded was for a corkscrew, which is the most challenging to build with the six feet of pipe.  Here are a couple of examples of corkscrew designs that worked.

The most popular design by far was the loop.  It also resulted in some good learning, too.  One group in particular was struggling with their loop.  The marble was making it about 2/3 of the way up the loop and falling out.  They couldn't figure out what was wrong.  I sat with the group and started asking them questions:

Why is the marble falling out?

          Ans:  It is not going fast enough

How can you help it get up the loop?

         There was a bit of discussion among the group, I hinted that there were a couple of solutions, so finally they decided to make the ramp or beginning of the coaster higher.

They tested it again, and it made it up a bit farther up the loop, but was still dropping out.  We discussed the problem some more, but they didn't have enough track to make the coaster any higher.  After more discussion among themselves and some gentle hinting on my part, they decided to make the loop smaller.  

Voila!  It worked!

Another group that had a valuable lesson was the group below.  They built a loop with a 90 degree turn.  I asked at the end of the session if anyone had had any problems to overcome and they said yes.  They first had the track flat and the marble flew off the track.  After some trial and error and thinking on their part, they realized they had to bank the track to get it into the cup!  Good thinking girls!

The biggest challenge of the day, besides the noise (which was all very joyful), was keeping some of the groups from changing their design constantly.  Some groups felt that they had to try every possible design and in the end had nothing to share with the class.  I tried to get the groups to experiment, decide upon a design, get it working and stop to share with the class.  A couple of groups just couldn't stop experimenting, they were having too much fun!  The other challenge was that a couple of groups just wanted to get the marble down the track with no twists or turns, so they needed a little encouragement to try new things, and step out of their comfort zone.

This was a great experience for all of us, students, teachers, parents, and me!