This is a presentation for a science lesson plan using gecko feet as inspiration for new technology, innovation and products.

1. “Sticking” with the Gecko

2. Van der Waals Forces and
Animal Adhesion
www.whyfiles.com
http://www.gotpetsonline.com/pictures-gallery/reptile-
upload.wikimedia.org
pictures-breeders-babies/tokay-gecko-pictures-breeders-
babies/pictures/tokay-gecko-0005.jpg

3. Activity Goal
• Explain how geckos and jumping spiders
use van der Waals forces to adhere to
surfaces
• Explain the relationship between mass of
an organism and number of setae/100 m2
• List some potential applications that use
gecko/jumping spider adhesion properties

4. Terms to Know
• Micro
symbol:
definition: one millionth or 10-6
• Micrometer or micron
symbol: m
definition: one millionth of a meter
a human hair is about 50 m wide
http://images.google.com/imgres?imgurl=http://www.nsf.gov/od/lpa/news/03/images/wir
e_on_hair_big.jpg&imgrefurl=http://www.nsf.gov/od/lpa/news/03/pr03147_images.htm&
h=960&w=1228&sz=197&hl=en&start=3&sig2=rkwzYL2bDxq6t_bdIfOY-
Q&um=1&tbnid=Y9V-_MzcLrD-RM:&tbnh=117&tbnw=150&ei=EvDfR-
zxI4_eigGbwcTUBQ&prev=/images%3Fq%3Dhuman%2Bhair%2B%26um%3D1%26hl
%3Den%26rlz%3D1T4GGLJ_enUS248US253

5. Terms to Know
• Nano
symbol: n
definition one billionth or 10-9
• Nanometer
one billionth of a meter

6. 1 cm 1 mm 100 m
The Nanoworld
10 m
0.1 nm 1-10 nm 1 m
http://microcosm.web.cern.ch

7. Terms to Know
• Nanotechnology
the control of shape and size at the nanoscale to
design and produce structures, devices, and
systems

8. Terms to Know
• INTERmolecular Forces
– Weak forces of attraction between
molecules (i.e. dispersion, dipole- -
dipole, dipole-induced dipole, hydrogen
bonds)
– Much weaker than intramolecular
forces
• Van der Waals Forces -
– Forces that arise when a temporary
dipole in a non-polar molecule induces
a dipole in an adjacent non-polar
molecule

9. Terms to Know
http://en.wikipedia.org/wiki/Tokay_gecko
Tokay Gecko (Gekko gecko)
an insect-eating, noisy reptile from South East Asia
• Scansors
lamellae or gill-like structures on the bottom of the foot
• Setae
hair-like bristles that come out of the scansors
• Spatula
branches from the setae that end in flat triangles

10. Gecko Morphology
http://images.google.com/imgres?imgurl=http://ist-
socrates.berkeley.edu/~peattiea/gecko_foot_tour.jpg&imgrefurl=http://socrates.berkeley.edu/~peattiea/research_main.html&h=365&w=578&sz=77&hl=en&start=13&sig2=4K8MfL4Nukg2ujB
4fltpEw&um=1&tbnid=F98wzSz5PBo28M:&tbnh=85&tbnw=134&ei=CfXfR-
bxLpiCiAGXrfzDBQ&prev=/images%3Fq%3Dgecko%2Bsetae%26um%3D1%26hl%3Den%26rlz%3D1T4GGLJ_enUS248US253

11. Terms to Know
http://whyfiles.org/shorties/152sticky_spider/
Photo courtesy Ed Nieuwenhuys
Jumping Spider (Evarcha arcuata)- a species of
jumping spider primarily found in Europe
• Scopula
protrusion found at the tip of each foot
• Setae
hair-like bristles that come out of the scopulae
• Setules
densely cover the setae and broaden into flat, triangular
end

12. a) Tarsal claws, scopula and
hairs
b) Scopulas differentiation into
setae
c) Single setae covered with
setules
d) Setule density is lower on
upperside of the setae
e) Setules on the underside
broaden to a flat, triangluar
end
f) The spider’s elements that
are in direct contact with the
substrate
Getting a Grip on Spider Attachment: an AFM Approach to
Microstructure Adhesion in Arthropods
Antonia B Kesel, Andrew Martin, Tobias Seidl

13. Station 1—Graph Interpretation
lizards Arzt, Eduard, Stanislav Gorb, and Ralph Spolenak
Proc Natl Acad Sci U S A. 2003 September 16; 100(19): 10603–10606.
Published online 2003 September 5. doi: 10.1073/pnas.1534701100.
Copyright © 2003, The National Academy of Sciences
spiders
flies
bugs
beetles
Q: What do each of the colored regions represent?
Q: What happens to the number of setae per 100 m2 as the mass of the
organism increases?
Q: What kind of relationship is this?

14. Station 1—Graph Interpretation
Arzt, Eduard, Stanislav Gorb, and Ralph Spolenak
Proc Natl Acad Sci U S A. 2003 September 16; 100(19): 10603–10606.
lizards Published online 2003 September 5. doi: 10.1073/pnas.1534701100.
Copyright © 2003, The National Academy of Sciences
spiders
The following pictures
flies are Scanning Electron
bugs Microscope pictures of
an animal’s foot.
beetles Match each picture
with the correct
organism: beetle, fly,
spider, lizard
flies lizards beetles spiders

15. Station 2—Experiment
How does the number of setae affect the strength of the
attachment force?
Mass chosen to weight # of “setae” 4 8 16 32
down toothbrush
_________________
Surface chosen
Total
__________________ Force (N)

16. Station 3—
Applications/Biomimetics
• 2 Articles for students to read about newly designed gecko-
tape.
• http://www.scientificamerican.com/article
.cfm?id=gecko-inspired-adhesive-s
“Gecko-Inspired Adhesive Sticks It to
Traditional Tape”
• http://www.sciencedaily.com/releases/20
12/02/120216165500.htm “Gecko Feet
Inspire Amazing Glue That Can Hold
700 Pounds On Smooth Wall”

17. Station 3—
Applications/Biomimetics
• 2 Articles cont.
• Answer questions relating to:
– Advantages gecko tape might have over conventional tape
– Problems in the manufacturing and use of gecko tape
– Distance of setae to substrate
(nanometer scale)
– Methods of adhesion in the gecko
(van der Waals forces)
– Gecko and spider feet morphology

18. More Recent Developments
Stanford University’s Sticky Bot
http://web.mit.edu/newsoffice/2008/adhesive-0218.html
MIT’s dissolvable medical adhesive
http://www.lclark.edu/~autumn/dept/Blog/4FB9A0EB-5911-4000-9D05-B1048F01E6C9.html

19. Station 4—SEM Images
WhyallHow gecko’sthedetach? stuck to asoflat ends? different?
If do picturesgeckos/spidersto having and look same
Why do they& “d” were have spider atsetae?
of aWhat is SEM Images, read, many the
do “c” advantage
Students studysetae for the Jumping surface answer
time, how manysetaeall have thespider morphology the top
questionsgreater surface to be be an angle greater than lbs!
the bottom ofpounds would it at able orientation 286 30o
they about gecko has a correct tosetules than
their not setae area lot more support?
may the need and
Gecko
Jumping Spider

20. Station 5 — Spider Student?
How many setae/100 m2 a 130 lb person
would need to stick to a wall?
y = m (x) + b
log (NA) = 0.699 log (m) + 13.8 lizards
spiders
flies
bugs
beetles

21. The equation for the best-fit line on the graph can be written:
y = m x + b
log(NA) = 0.699 log(m) + 13.8
log of log of setae per 100 m2 log of mass of organism in grams
How many setae/100 m2 would a 130 lb person need to stick to a wall?
1st: Convert 130 lbs to grams. mass = 59090 g
2nd: Substitute this value into the equation of the straight line.
log(NA) = 0.699 log(59090) + 13.8
NA = 1.37 X 1017setae/100 m2
3rd: Convert this to setae / 100 cm2
NA = 1.37 X 1023 setae / 100 cm2

22. References:
Gecko pic- http://images.iop.org/objects/phw/news/12/10/14/Gecko.jpg
Gecko pic 2- http://www.exoticpetswholesale.com/i//sm_blue_gecko02.jpg
Tooth brush pic - http://www.kosherimage.com/images/tbrush-4layflat.jpg
Spring scale pic- http://www.enasco.com/prod/images/products/2A/VC131047l.jpg
This powerpoint comes from site below and was modified to meet needs of students.
teachers.oregon.k12.wi.us/ehrlich/NSTA08%20%20presentation.ppt