Demonstration (Vilasinee)

Title: The title should be descriptive so others will know what it is about

Nitinol: memory metal

Principle(s) Investigated: List all principles that apply to this activity

Super elasticity

v rubber-like deformability of shape memory alloys

v will not experience deformity

Shape memory alloy

v takes (1) form at a certain temperature & transforms into another shape when heated

Austenite

v "parent stage"

v simple cubic structure in an ordered crystal lattice

Martensite

v "daughter stage"

v homogenous movement of atoms that results in a change in crystal structure at one temperature

v recovers its original undeformed shape upon heating

v the soft, bendable, low-temperature phase of nitinol

Standards: Paste in the appropriate California content standards

5th grade

(Physical science)

1. Elements and their combinations account for all the varied types of matter in the world. As a basis for understanding this concept:

a. Students know that during chemical reactions the atoms in the reactants rearrange to form products with different properties.

b. Students know all matter is made of atoms, which may combine to form mol­ecules.

c. Students know metals have properties in common, such as high electrical and thermal conductivity. Some metals, such as aluminum (Al), iron (Fe), nickel (Ni),copper (Cu), silver (Ag), and gold (Au), are pure elements; others, such as steel and brass, are composed of a combination of elemental metals.

d. Students know that each element is made of one kind of atom and that the ele­ments are organized in the periodic table by their chemical properties.

e. Students know scientists have developed instruments that can create discrete images of atoms and molecules that show that the atoms and molecules often occur in well-ordered arrays.

8^th grade

(Physical science: Forces)

Unbalanced forces cause changes in velocity. As a basis for understanding this concept:

d. Students know how to identify separately the two or more forces that are acting on a single static object, including gravity, elastic forces due to tension or compression in matter, and friction.

e. Students know that when the forces on an object are unbalanced, the object will change its velocity (that is, it will speed up, slow down, or change direction).

f. Students know the greater the mass of an object, the more force is needed to achieve the same rate of change in motion.

9^th-12^th grade

(Physical science: Conservation of Energy and Momentum)

2. The laws of conservation of energy and momentum provide a way to predict and describe the movement of objects. As a basis for understanding this concept:

h.* Students know how to solve problems involving conservation of energy in simple systems with various sources of potential energy, such as capacitors and springs.

Materials: Include a list of materials and sources from which they may be obtained

Nitinol

Lighters

Tweezers

BIC lighters

Bowls

Water (hot + cold)

Nails (optional)

Rubber band

Paper clip

Procedure: Give a detailed explanation of the procedure and include diagrams if possible

Ask students what elements nitinol is composed of, refer them to the periodic table

Review what an alloy is and inform that nitinol is an alloy comprised of nickel and titanium

Reiview that metals expand when heated and use a bimetallic strip to model

Allow the students to explore and discover the properties of nitiniol

Have them hold their sample under a flame

Ask them to describe their findings

Discuss the memory shape and elasticity properties of nitinol

Differentiate between plasticity and elasticity

Explain how to “set” (anneal) nitinol (exposure to 500 degrees Celsius followed by cold water dunk)

Allow students to “set” their own samples

Have them test if it worked (deform it and reheat)

Introduce the stages of nitinol (martensite and austensite)

Ask the students to identify which stage their samples were at specific points during the lab

Have each group google different categorizes of nitinol applications and share two findings with each other.

Close with samples of nitinol engines and the elastic energy it posseses.

Exerts 55 tons per square inch

heat converted directly into mechanical energy

gets stronger and more stable the longer it runs

cost: $600/kw

Nitinol (memory shape using hot water)

Nitinol (Scientific Tuesdays: why + energy)

Nitinol engine using ice + hot water to run it

Student prior knowledge: What prior concepts do students need to understand this activity?

Metals expand when heated.

Nitinol

v nearly equal parts of nickel and titanium

Alloy

v mixture or metallic solid solution composed of two or more elements

v combining it with one or more other metals or non-metals that often enhance its properties

Annealing

v in reference to metallurgy and materials science

v a heat treatment wherein a material is altered, causing changes in its properties

Bimetallic sensor

v object that is composed of two separate metals joined together in layers

v convert a temperature change into mechanical displacement

Explanation: Give a thorough explanation of the experiment or demonstration. Your explanation should be written to give your fellow teachers a solid understanding and include greater detail than what you might provide for your secondary students. Make certain to include equations whenever pertinent.

The students will be given time to explore the characteristics of nitinol for themselves.

(A) Explore nitinol’s shape memory property

1. Give each group a piece of nitinol

2. Allow them to deform it to any shape they want (not allowed to cut/break it up)

3. Have them place it in a bowl of hot water to watch it revert to its austenite structure

The students will be given time to learn how to anneal nitinol.

(B) The annealing process

1. The nitinol is currently in its martensite stage

2. Have them decide on their “shape”

3. The wire must be rigid and set if the shape is complicated (square/circle)

4. Have the students anneal it over an open flame

5.

Provide them (2) bowls, one for hot water and one for cold water. Also give them a piece of nitinol and a BIC lighter.

(C) Testing

1. Have them deform their sample

2. Have them place it in a bowl of hot water

3.

Questions & Answers: Give three thought-provoking questions and provide detailed answers

1. What other applications can nitinol provide? Reflect on how the force it exerts when assuming its “memorized” shape.

Nitinol is a source of potential elastic energy and can be harnessed to provide energy because it directly converts heat into mechanical energy.

2. Name sources which are provide waste heat.

Steel mills, cooling towers, nuclear plants, geothermal, light bulb, car exhaust, etc

3. Of the aforementioned types of waste heat sources, which could nitinol harness to create energy?

Depends on the answers that the class generates, but where there is a supply of heated liquid, substrate, and or electrical currents.

Applications to Everyday Life: Explain (don't just list) three instances where this principle can be used to explain other phenomenon

Medical

v self expanding stent/grafts

v elastic deployment of medical devices

v suture anchors

v orthodontic brackets & wires

v orthopedic implants

v surgical instruments (open & close w/o hinges)

v bone staples

Consumer products

v safety shower heads (auto shut off at specific temperatures)

v golf clubs

v coffee makers

v car’s transmission fluid spring valve

v eye glass frames

v greenhouse window openers

v folding bicycles

v fire sprinklers

v toys

v magic tricks

v fishing lures (releases w/o breaking)

v deep fryers

Robotics

v actuators

v micro-valves to control pneumatic devices

v mice-manipulators

Structural

v anchors

v connectors

v structural reinforcements

v shape restoration (“closes” cracks in cement blocks)

v bracing elements

v damping elements for bridges & wheels

Aircrafts

v hydraulic tubing (military aircraft)

v Mars rover

v helicopter rotor blades (control balance)

Visual aids:

Austenite to martensite transformation

Two way memory effect (cold + hot)

Elastic &spring potential energy calculator, images, & equation

http://hyperphysics.phy-astr.gsu.edu/hbase/pespr.html

Bimetallic sensor

References:

Terminology

http://www.memry.com/nitinol-iq/nitinol-resources/glossary

History

(THE CHEMICAL EDUCATOR Volume 2, Number 2, 1-21, DOI: 10.1007/s00897970111a)

http://www.springerlink.com/content/t0h1618327488j1w/

Comprehensive CNN vdo (14.30 minutes)

http://www.youtube.com/watch?v=ZoAFc_DeWVQ

Nitinol: melt to market

http://www.youtube.com/watch?v=gabhTX3qG8s&feature=related

DYI annealing + demos

http://www.youtube.com/watch?v=smuCwUKyhkg&feature=related

Nitinol labs for students

http://www.ccmr.cornell.edu/education/modules/documents/Nitinol.pdf

http://mrsec.wisc.edu/Edetc/modules/MiddleSchool/Memory/Investigation3.pdf

Medical applications

http://www.nitinol.com/media/reference-library/029.pdf

http://www.nitinol.com/media/reference-library/029.pdf

A very (dry but) comprehensive site

http://www.scribd.com/doc/12702945/55Nitinol-The-Alloy-with-a-Memory-NASA-Report

Nitinol engines

http://scholar.lib.vt.edu/theses/available/etd-02102001-172947/unrestricted/ETD.pdf

Purchasing:

Coils

1. http://musclewires.com/Products.php

2. http://www.ebay.com/itm/3-NITINOL-55-Finest-AAA-Robotics-Grade-Trigger-Springs-120-F-Reaction-/110760710735?pt=LH_DefaultDomain_0&hash=item19c9da524f#ht_500wt_1202

3. http://www.ebay.com/itm/5-Nitinol-Shape-Memory-Alloy-springs-45-C-113-F-activation-/260856891878?pt=LH_DefaultDomain_0&hash=item3cbc4849e6#ht_736wt_952

Pieces

1.http://www.ebay.com/sch/kelloggsresearchlabs_com/m.html?_dmd=1&_ipg=50&_sop=12&_rdc=1 DO NOT BUY FROM THEM. DOES NOT WORK WITH HOT WATER AS IT SHOULD!!! Amongst other things!!!! ARGH!!!!!!!!

2. http://www.imagesco.com/nitinol/livewire.html

3.http://www.teachersource.com/Energy/MemoryMuscleWire/MemoryWireSamples_pkof10.aspx

4. http://www.tinialloy.com/livewire.html

Learning curve:

Many sites & videos show that nitinol will transform using hot water. However, from my (numerous) trials at home, this has not been the case. It could be due to the quality of the wire I purchased, but my samples only worked with a flame. I did not test it with a hair dryer, hot substrate (sand/salt), or with an electric current.

Also, it is very frustrating “setting” the nitinol into a tight coiled form for the presentation to show the potential elastic energy properties. However if you have a board, nails, and hammer I’m pretty sure that annealing various other shapes should be no problem (with better grade wire than I used).