French team presentation of the "Express Yourself" international conference - May 2014 Présentation de l'équipe Française pour la conférence internationale "Express Yourself" du dispositif européen Chain Reaction

1. How to predictHow to predict
the size of anthe size of an
asteroid crater?asteroid crater?
Lycée Doisneau – Vaulx-en-Velin
France
InternationalInternational Express YourselfExpress Yourself ConferenceConference
Sheffield Hallam University – May 13, 2014Sheffield Hallam University – May 13, 2014
Rémi GUILLET
Amani HAMDI
Amel MAHAMDI
Tahanie MEJRI
Zeynep SAN
Spokespersons
of a group of 45
French students

2. Our hometown is located next to Lyon
Lyon
Lyon
the 2nd biggest city
in France
Vaulx-en-Velin
in the suburb
of Lyon
Paris

3. Our school : the Lycée Doisneau

4. « We have nothing to fear but… »
Albert UDERZO, Asterix and the falling sky, 2005

5. How to predict the size of anHow to predict the size of an
asteroid crater?asteroid crater?
1. Problem presentation

6. Localisation of the asteroids
A picture of the solar system
http://www.nasa.gov
Map of the asteroids
in the inner solar system
restated on May 9, 2008
http://www.greatdreams.com/near.htm

7. Diversity of the asteroids
http://www.paperblog.fr/4691619/la-sonde-spatiale-dawn

8. Object
Name
Close Approach
Date
Close Approach
Distance (LD*)
Estimated
Diameter
Relative
Speed (km/s)
(2008 TA1) 2014-05-13 58.2 480 m - 1.1 km 14.57
(2013 WU44) 2014-05-15 63.4 180 m - 410 m 11.24
342866 (2008 YU32) 2014-05-15 57.5 240 m - 540 m 14.04
(2010 SO16) 2014-05-16 65.6 210 m - 470 m 10.02
(2010 JO33) 2014-05-17 4 27 m - 59 m 8.19
(2007 VD12) 2014-05-17 62.3 270 m - 590 m 13.11
(2014 FP47) 2014-05-18 37.4 88 m - 200 m 5.64
(2014 GD50) 2014-05-19 38.4 280 m - 630 m 23.98
(2013 XS23) 2014-05-19 46.5 15 m - 33 m 5.83
225312 (1996 XB27) 2014-05-20 44.8 110 m - 240 m 0.84
242708 (2005 UK1) 2014-05-20 36.7 670 m - 1.5 km 19.57
(2011 JR13) 2014-05-21 19.7 320 m - 710 m 27.19
21374 (1997 WS22) 2014-05-21 47.1 920 m - 2.1 km 12.54
(2010 UQ7) 2014-05-21 50.2 270 m - 590 m 20.63
(2014 FA44) 2014-05-23 14.7 28 m - 63 m 2.37
(2007 VK184) 2014-05-23 67.3 110 m - 240 m 20.72
(2000 TL1) 2014-05-23 64.9 73 m - 160 m 11.92
One near-Earth object every day !
Upcoming close approaches to Earth
* 1 LD = Lunar Distance ≈ 385 000 km http://neo.jpl.nasa.gov/ca/
Next saturday

9. Object
Name
Close Approach
Date
Close Approach
Distance (LD)
Estimated
Diameter
Relative
Speed (km/s)
(2010 JO33) 2014-05-17 4 27 m - 59 m 8.19
Our problem
If this asteroid (as big as a building)
crashed on Earth,
what would be the size of the impact crater?
http://www.intellego.fr/aide-scolaire-svt/photos-meteor-crater-barringer

10. How to predict the size of anHow to predict the size of an
asteroid crater?asteroid crater?
1. Problem presentation
2. Experimental design

11. Impact crater simulation
Situation studied Simulation
Impactor Asteroid Marble
Impact surface Earth (rocks) Basin of flour, sand, compost...
Principle of the experiment

12. Influential variables
fixed: flat and horizontal ground
fixed: vertical fall
varying: flour, semolina, sand,
(compost, sawdust...)
varying:
from 30 cm
to 2 m
fixed: spherical
A few trials with
different balls, then
fixed: a big glass
marble of 21 g

13. Formation of an impact crater
Vincent Langlois,
from the Geology Laboratory
of the University of Lyon
http://ufe.obspm.fr

14. Necessity to choose a powdering ground
Wet sandSoft clay
http://cm1cm2.ceyreste.free.fr/formes.html http://www.impact-structures.com

15. How to predict the size of anHow to predict the size of an
asteroid crater?asteroid crater?
1. Problem presentation
2. Experimental design
3. Observations and measurements

16. Experimental procedure

17. Visual observations
=> There is evidence of matter ejection during the impact.

18. Measurements
Flour + layer of cacao powder
E=m⋅g⋅h
A marble dropped from the height h
crashes on the flour with the energy
where m is the mass of the marble (kg),
g is the gravitational field strength (on Earth, g = 9,81 N/kg),
h is the height of the fall (m)
E is the energy (J)
E=m⋅g⋅h

19. Measurements
Fine semolina
Medium-grained semolina Sand

20. How to predict the size of anHow to predict the size of an
asteroid crater?asteroid crater?
1. Problem presentation
2. Experimental design
3. Observations and measurements
4. Data analysis

21. Evolution of the crater diameter
depending on the marble energy
The finer the soil texture, the larger the crater.
The points have a regular and accurate evolution when the soil is the fine semolina. The
software LibreOffice calculated the equation of the best fit curve:
D = 0.12 × E 0.26
D = 0.12 × E 0.26
Best fit curve (flour)
Best fit curve (fine semolina)
Best fit curve (medium semolina)
Best fit curve (sand)

22. Object
Name
Close Approach
Date
Close Approach
Distance (LD)
Estimated
Diameter
Relative
Speed (km/s)
(2010 JO33) 2014-05-17 4 27 m - 59 m 8.19
Extrapolation: principle
We are going to make the hypothesis that when an asteroid
crashes on Earth, it is like when a marble falls in fine semolina.
Therefore, the crater diameter (D in meter) is related to the
asteroid energy (E in Joule) by the formula D = 0.12 × E 0.26
.
BACK TO THE
PROBLEM
=> First, thanks to the data of the table, we are going to calculate the
energy E of the asteroid.
=> Then, we are going to use the formula we have established
(D = 0.12 × E 0.26
) to find the crater diameter D.
Next saturday

23. D=0.12×(6.7×1015
)0.26
≈1.6×103
m≈1.6 km
Extrapolation: application
Volume V of the asteroid which will approach next saturday (diameter: 50 m)
V =
4
3
 R
3
V =
4
3
π(
50
2
)
3
=65×103
m3
Mass m of the asteroid
Density of the asteroid: ρ ≈ 3.0 × 103
kg/m3
(like Earth's rocks)
m=3.0×10
3
×65×10
3
≈2.0×10
8
kg
Energy E of the asteroid (velocity: 8.19 km/s)
E=
1
2
mv² E=
1
2
×2.0×10
8
×(8.19×10
3
)²=6.7×10
15
J
Diameter D of the impact crater
D=0.12×E0.26

24. Comparison of our results
with those of scientists
What we have found
A 50 meter-diameter asteroid makes a 1.6 kilometer-wide crater.
Elements of comparison
The same order of magnitude

25. Automatic calculations

26. How to predict the size of anHow to predict the size of an
asteroid crater?asteroid crater?
1. Problem presentation
2. Experimental design
3. Observations and measurements
4. Data analysis
5. Conclusion

27. Conclusion
 What we found
- we can simulate an impact crater at a small scale using semolina instead
of rocks
- we can predict the diameter D of the crater resulting from the impact of an
asteroid releasing the energy E, using the equation D = 0.12 × E0.26
 Limitations of the experimental design
- measurements are not always reliable => to replicate
- the marble is not heavy enough and speeds are too small => to try with a
lead ball on higher falling heights
 Limitations of the simulation
- we did not take into account the atmosphere!!! (friction, fragmentation...)
- we did not consider the fact that a part of the energy of the asteroid is not
used for the cratering process (melting of rocks...)

28. French National Conference

29. French National Conference

30. Aknowledgments
 To all our classmates:
Thomas ABDEDOU, Adel ARIOUI, Mohamed BAKKALI, Soleyman BELAFEKIR, Ilhem
BENHARRAT, Chaïma BEN YAHIA, Amandine BILLON, Ninon BLANCHARD, Wassil
BOUGUELMOUNA, Soummaya BOUTARA, Sonia BOUZERD, Océane CLOSSET,
Jade DAURIAT, Binta DIALLO, Soumia FARTAS, Evren GUNGOR, Anissa HASSI,
Pascal HUYNH, Zeineb JERIBI, Horlin KOPA, Hoang-Yen LAM, Fabien ONNIS, Julie
PIGA, Amina SAMSAR, Dylan SIMOES, Bilel SOUFI, Katya YAHAOUI, Sarah
ZAHOTE, Ange ZONGO
 To our teachers:
Ms CHENEY, Mr. ARNAUD and Mr. LANDRY
 To CIFOP and
the european program Chain Reaction
which enabled us to share our work with you
Thank you for
your attention :-)))
GOSCINNY and UDERZO, Asterix