GRNG Exploratory Sept 30th- Protests, DC Motors

Discussion of Confederate flag issue and student meeting; tension in the school. School should be a neutral zone.

Students are better connected than the teachers via social media.

Next- Solar and the economics of solar. Next week- solar chimney challenge.

How do brushless DC motors work?-See http://electronics.howstuffworks.com/brushless-motor.htm--
permanent magnets are on rotor, stator fields controlled electronically:

Related to Stepper Motors:

Windmill challenge--see Kidwind Curriculum Material
 http://www.kidwind.org/windwise-1 

Experimented with DC Motors- connecting a load makes them harder to turn.

Lego RCX motors very efficient generators.

GRNG 201/301 Sept 30th Aquaponics System, Paper Rocket Launcher

Students worked on aquaponics system plumbing and clay pellets.

Next steps- add controls. Mr. P will get plants ( mint, basil) to begin planting. Adjustments were made to the pumping system using a less powerful pump, which runs on 12V-- will need a power supply.

Students added hydroton clay pellets to the system. When done, pellets are surrounded by water, but not floating.

How can we get students to redesign system to make it more cost-effective and modular? People stick to what they have done in the past.

At MakerFaire NYC: Martha's Vineyard Regional High School- Natalie Munn
 http://www.need.org//Files/Youth%20Awards/2016projects/MarthasVineyardRegionalHighSchool.pdf

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Worked on Paper rocket launcher- pressurized system- found leaky joint using soapy water, sealed using plastic epoxy, sealed other joints.

Leak remained at electric valve-- replaced with manual valve, which then held pressure.

GRNG 101- Sept 29th- Prototyping Backpacks

Students began prototyping their designs for backpacks, using recycled materials.

Many designs had complex pockets, webbing, and other features.

Several students utilized closed-cell foam for padding and other features.

Cordura is the brand name for a collection of fabrics used in a wide array of products including luggage, backpacks, trousers, military wear and performance apparel. Cordura fabrics are known for their durability and resistance to abrasions, tears and scuffs.

Originally developed and registered as a trademark by E.I. du Pont de Nemours and Company (DuPont) in 1929, it is now the property of Invista (a wholly owned subsidiary of Koch Industries).^[1] Cordura fabrics are usually made of nylon, but may be blended with cotton or other natural fibers.

LL Bean:

 
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Other notes: Glued cap with tire valve onto paper rocket launcher.

Dr. Tupper recommended:

•  Installation of a pressure relief valve before the flow valve in case of overpressurization- http://www.homedepot.com/p/3-4-in-Cast-Iron-Water-Pressure-Safety-Relief-Valve-374A/100532582?cm_mmc=Shopping%7cTHD%7cG%7c0%7cG-BASE-PLA-D26P-AirCirculation%7c&gclid=CIfoz_autc8CFc5ahgodkYgI_g&gclsrc=aw.ds  ?
• Taping the pressurized chamber in case of fracture
• Orienting the launch tube at an angle of 37 degrees.

Sept 28th- Grng 201- Aquaponics Tank, Rocket Launcher

Students worked on aquaponics system, experimented with pump. Mr. P. wants drawings and blogposts to be done.

Also worked on NASA-Based Paper Rocket Launcher. Cut PVC with hacksaw, glued together. Scott Rosenhahn supplied a lawn sprinkler valve. Glued in tire valve with plastic epoxy.

GRNG Exploratory Sept 26th - Solar Cell Challenge

Photovoltaic cells produce electricity by photons dislodging electrons from n-type semiconductor:

Each individual cell can produce up to 0.5V at 500 mA:

The challenge is to light an LED. An LED has a forward voltage drop of 1.5V to 3.5V, depending upon color, and requires between 15 mA and 35 mA of current:

Direct sunlight has significantly more light intensity than sunlight through a window.

"Green" solutions to energy needs may or may not be the most efficient or eco-friendly....you have to anylyze the complete life-cycle costs, etc.

Determining maximum power efficiency

Grng 101 Sept 26th- Sewing and Prototyping

Demonstration of Janome DC2010 Sewing Machine, for sewing backpacks:

Thread on top, bobbin on the bottom.

For sewing edges, find a zig-zag stitch- #10 or #11; press button to select stitch.

Don't sew too close to the edge. Some material will fray- use adhesive.

Control speed with the foot pedal.

Raise the presser foot with the lever.

For straight seams use a straight stitch- #1. The material will feed itself.

Put the right sides together. Set tension to 3 or 4.

How to thread a Janome Sewing Machine:

GRNG Exploratory Sept 23rd- Batteries Part 2

Students continued working on penny batteries-

Some more groups got LEDs to light:

Another group was able to power a calculator:

I experimented with a new version of the aluminum/bleach battery:

It produced about 60 mA at 4.5V.

Another version of the copper-aluminum-bleach battery used baggies. It was able to run a small motor, but it had some leakage issues.

8.2V! The voltage slowly increased with use...

Mr. Peloquin opened up a 9V alkaline battery, and showed how it composed of multiple cells...

GRNG 201 Sept 23rd

Students worked on Aquaponics design-- need to do a CAD drawing of new system.

Showed students CAD drawings of InterMetro Shelving available at manufacturer's website.

Discussed building paper rocket launcher:

Sept 23rd GRNG 101- Design a Backpack

Review of IDEO "Deep Dive" Video  https://youtu.be/2Dtrkrz0yoU

See also: https://youtu.be/-SLk0CZjAw4 Ohio State

See http://steamcurriculum.weebly.com/uploads/2/5/5/8/25586003/201btcmpdeepdive.pdf

Assignment: By the end of class today,

1.  Come up with a list of requirements and constraints for your backpack design--

• Cost
• Range
• Weight capacity
• Special features- compartments for laptop, drink, etc.

   2. Make a sketch of your design, and share via Google Docs or on paper....

...."How Might we..."

   3. Make a list of who you want to interview for design --users, experts, etc.

     Survey Data-  look for contradictions and commonalities- should include what others tell you they want.

   - Be in contact with each other, go out and do surveys:

By end of class on Monday, be ready to start building your prototypes.

Why replace a backpack?

• Style
• Price
• Weight capacity

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Lunch Box compartment- insulated for heat

Kelty pack- excellent but expensive $$$-- ended buying a used Kelty for 50% off.

Process--what was your methodology?

-A lot of good work going on-

      - one group did online survey with pie charts

      - One group reverse-engineered existing backpack

      - one group did verbal surveys

Share your methodology-- how are you coming up with your ideas?

You Will learn the most from other students, not the teacher-- i.e. how did you make the Google Forms?

Links- Museum of Science Engineering the Future- backpack design.

Changing students from worksheet mindset to self-directed mindset-- takes time, doing many design challenges, not giving complete instructions- make them figure it out!

Weighing backpack . . .

Exploratory Sept 20th- Penny Batteries

Today-

We will be trying to light a light-emitting diode(LED) with the materials on the table-- pennies, cardboard, salt water, aluminum foil, LED's.

http://www.instructables.com/id/How-to-Turn-Spare-Pocket-Change-into-DIY-Batteries/

(1)Split into groups of 3 by counting off by 1 to 6.

(2) Spend time doing research, create a plan, and write it down, then show it to Mr. Peloquin before you start building.

• http://www.exploratorium.edu/snacks/penny-battery

• https://www.khanacademy.org/partner-content/exploratorium-ddp/exploratorium-chemistry/penny-battery/v/build-your-own-penny-battery-materials-steps

• Half-cell potentials
• http://hyperphysics.phy-astr.gsu.edu/hbase/chemical/electrode.html#c2

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What do you notice as you go?

• Materials touching
• Voltaic pile that worked- the soaked cardboard was cut off
• You have to sand the pennies thoroughly to expose the zinc--technique matters!

Voltage: A Measure of electrical force

Current: A measure of the flow of electrons

LED's have minimum specifications to work-

• 15- 20 mA
• 2V forward voltage drop
• On an LED, the long wire is positive

Electricity- The Basics https://itp.nyu.edu/physcomp/lessons/electronics/electricity-the-basics/

Sept 16th-Exploratory--Shop Safety/Capacitive Stylus

Shop Safety- wear safety glasses! Report Injuries! Avoid dangly things around power tools! Don't run!

up·cy·cle

ˈəpˌsīkəl/

verb

gerund or present participle: upcycling

1. reuse (discarded objects or material) in such a way as to create a product of a higher quality or value than the original.

   "the opportunity to upcycle trash, or turn it into new products, was vast"
2. 
   

UpCycling Resources:

http://www.upcyclethat.com

http://www.hgtv.com/design/topics/upcycling

http://www.diynetwork.com/how-to/make-and-decorate/decorating/19-upcycling-projects-from-salvage-dawgs-pictureshttp://www.diynetwork.com/how-to/make-and-decorate/decorating/19-upcycling-projects-from-salvage-dawgs-pictures

Capacitive Stylus
http://www.instructables.com/id/DIY-Capacitive-Stylus/

thin picture wire 

pen parts

 sponge 

(Scotch brite?)

 aluminum foil 

dowel/pencils

https://www.cnet.com/how-to/how-to-make-a-free-ipad-stylus/

Sept 16th- GRNG 101- Boat Design Challenge

The Greenengineering 101 students did another introductory design challenge:

Working in teams of 2, design a boat structure that will carry at least 25 pennies, and that will fit within the aquarium.

Available Materials: 

• Large Plastic Cup
• Duct Tape- 12"
• 10 plastic drinking straws
• 10" of plastic wrap
• 1 item from the prototyping bin.

The design above was very stable, as the pennies were below the waterline, lowering the center of gravity....

Straws serve to increase the initial stability of the boat....

Discussion:

Large variety of designs- in engineering, there are often many possible solutions.

Some design solutions tended to converge.

Ship stability - low center of gravity helps ship be more stable

https://en.wikipedia.org/wiki/Ship_stability

The ship is stable because as it begins to heel, one side of the hull begins to rise from the water and the other side begins to submerge. This causes the center of buoyancy to shift toward the side that is lower in the water. The job of the naval architect is to make sure that the center of buoyancy shifts outboard of the center of gravity as the ship heels. A line drawn from the center of buoyancy in a slightly heeled condition vertically will intersect the centerline at a point called the metacenter. As long as the metacenter is further above the keel than the center of gravity, the ship is stable in an upright condition.

Video:

Discussion: The Swedish ship Vasa  sank a few minutes into its maiden voyage due to an excessively high center of gravity:



https://en.wikipedia.org/wiki/Vasa_(ship)

"...Vasa sank because it had very little initial stability, which can be thought of as resistance to heeling over under the force of wind or waves acting on the hull. The reason for this is that the distribution of mass in the hull structure and the ballast, guns, provisions, and other objects loaded on board puts too much weight too high in the ship. 

The center of gravity is too high, and so it takes very little force to make the ship heel over, and there is not enough righting moment, force trying to make the ship return to an upright position. The reason that the ship has such a high center of gravity is not due to the guns. These weighed little over 60 tons, or about 5% of the total displacement of the loaded ship. This is relatively low weight and should be bearable in a ship this size. 

The problem is in the hull construction itself. The part of the hull above the waterline is too high and too heavily built in relation to the amount of hull in the water. .."