Research Project - Separating Things

Good work today, folks!  First things first: there’s some homework we need done for next week.

Homework:

Amy/Olivia/Tara: Investigate separating silicon from silicon carbide based on particle size.  Amy, could you ask your dad for his expert opinion?  What are the sizes of the particles in silicon wire-saw slurry? Are there filtering techniques for separating particles of those sizes?  Is anybody already doing this?  Are there existing methods for silicon recovery from wire-saw slurry?  Maybe you could search Google, including patents.google.com and books.google.com.

Neshaya: Investigate separating silicon carbide from silicon based on density.  What are the densities of silicon and silicon carbide?  Is there a liquid with a density in between the densities of silicon and silicon carbide, that would allow one to float and the other to sink?  Is anybody already doing this?  Are there existing methods for silicon recovery from wire-saw slurry?  Maybe you could search Google, including patents.google.com and books.google.com.

Erika/Jadzia: Investigate separating silicon from silicon carbide based on magnetic properties.  Dr Linton suggested that because silicon is more conductive than silicon carbide, maybe you could separate it with a magnet.  Could you look up repelling conductors with a magnet?  Youtube and Google could be good places to look.

Nick: Investigate separating silicon from silicon carbide based on melting points. What are their melting temperatures?  If one melts at a lower temperature than the other maybe we could strain the solid out of the liquid like we do with coffee.  Or maybe the one that melts last would float or sink in the one that melts first, and the liquid could be poured out or drained.

Amy/Olivia: We need a timeline, pricing, and a decision on t-shirts. 

Tara/Amy: We need a Comet Warriors logo for the shirts.

As background to the homework, here’s a summary of what we did today:

We announced that Neshaya’s letter to the parent council got us $701.00!  Quite a letter and great job Neshaya!  The word for this week is “Neshaya”.

We reviewed the schedule and saw that we had only four weeks left before the tournament, including this week.  We’ve made good progress on the robot so far so we’re not too worried there.  We’re doing well on the core values and did another exercise on a) learning what those values are, and b) putting them to use in a card sorting exercise.  Remember: UPS!

We’re way behind on our research project so today we worked a lot on that.  The project is salvaging silicon sawdust, which is created when wafers are sliced from blocks of silicon.  Last week Olivia identified some things we might need for the project and we ordered them.  Based on Dr. Linton’s description, the problem is to separate silicon sawdust from the grit used to cut it, and the liquid it is mixed in.  The grit he said is used to cut it is “silicon carbide”, and the liquid it’s mixed in is “polyethylene glycol”.

Based on that description we ordered:
a) Silicon wafers
b) Powdered silicon
c) Silicon carbide dust
d)  Polyethylene glycol

Today we made a mixture of silicon, silicon carbide, and polyethylene glycol in a bottle to see what we had to work on.  It looked like a bottle of dirty water.

To get some ideas of how to separate things in general, we tried some experiments on a few more familiar mixtures. 

Separating Sawdust, Iron Filings and Sand

Sawdust, Sand, and Iron Filings

We started with a mixture of sawdust, iron filings, and sand and brainstormed ideas on how to separate them.  The ideas were:

Nick: Sift the mixture, or burn the sawdust.

Erika: Put the mixture in water to make the sawdust float.

Jadzia: Shake the mixture to make the iron and sand sink to the bottom.

Olivia: Use a magnet to pull out the iron filings.

We tried a combination of the different ideas.  We put the mixture in water, and the sand and iron sank to the bottom.  We then dragged a magnet along the bottom and pulled out the iron.  That left the sawdust floating, the sand at the bottom of the tank, and the iron stuck to the magnet.  Problem solved!

Separating Golf Balls, Ping Pong Balls and Mochi Ice Cream Balls

Mochi Ice Cream, Ping Pong, and Golf Balls

We then looked at a second problem: Separating a mixture of ping pong balls, golf balls, and mochi ice cream balls.  We brainstormed again and the ideas were:

Olivia: Heat them to make the ice cream melt

Nick: Give them to squirrels, who would eat the ice cream balls

Neshaya: Raffle them off and separate them by price

Olivia: Bounce them to see which bounce the highest

Nick: Separate them by color.

Olivia: Run them over grates with different size holes and the ping pong balls would fall through the smallest holes, the golf balls through the next larger holes, and the mocha ice cream through the biggest holes.

We again tried a combination of ideas: we ate the ice cream, and bounced the ping pong and golf balls.  The golf balls bounced highest, and if we bounced both types of ball on the floor the golf balls could bounce into a garbage can and the ping pong balls wouldn’t.

Our Research Project

Silicon, Silicon Carbide, and Polyethylene Glycol

We talked about how we came up with the different separation ideas. We had looked at the differences in the things we needed to separate: size, density, weight, melting point, color, magnetic properties, elasticity, color, smell.  We call these things "properties" or "attributes".

We decided to investigate the properties of silicon, silicon carbide, and polyethylene glycol and see what differences in properties we could use to separate them.  As described above in the Homework section, people volunteered to study certain properties and see if we might be able to solve our problem based on those properties, and to see if others had tried or were already using similar methods.

Let’s see what we can learn by next week and bring the information to our Tuesday meeting.  Thanks!