galileo's assistant
TRANSCRIPT
Become Galileo’s assistant
EdgarMartiarena
Introductory section and preparatory phase
• Short Description: Galileo was really confused about the geocentric system. He was strongly convinced that sun is in the center of our planetary system, so he was looking for undoubtedly evidences. Then he got the idea to target his telescope to Venus. According to the geocentric system (Ptolemy’s Model) it would not be possible to view all Venus in all phases, but only as a meniscus. But, when he pointed his telescope at Venus he saw all phases from full phase to new Venus. This was an ultimate evidence of the heliocentric system. Furthermore, Galileo turned his telescope to Jupiter revealing for the very first time the moons of Jupiter. These were the first observed planets orbiting around another planet and not around Earth. Imagine now being the assistant of Galileo recording all his observations and claiming explanations. This is now your role. Become Galileo’s assistant!
• Keywords: Heliocentric, geocentric, Venus, phases, Jupiter, Galileo.• Target audience: Students studying Physics and Astronomy.• Age range: 12-18 years old• Context: Science Lab, Computers Lab, Internet Connection, Stellarium,
SalsaJ (both free software available on internet). • Time required: 6 hours
Introductory section and preparatory phase
• Technical Requirements: Internet connection, appropriate software: Stellarium, SalsaJ, connection to YouTube, Computers, video projector could be useful.
• Author’s background: Knowledge of Physics, knowledge of Astronomy, Stellarium, SalsaJ, use of internet. Geocentric model (Ptolemy’s model), Heliocentric model, methodology of Galileo, finding of evidences for the heliocentric model, solar system (use of Wikipedia can be useful).
• Connection with the curriculum: Strongly related to Astronomy (First, Second and third Class of Junior High School), Physics (First, Second and Third Class of Junior High School and First Class of High School). Partly related to Philosophy and ideas of astronomers and philosophers (Ptolemy, Copernicus, Galileo).
• Learning Objectives: Hands on learning, Inquiry based learning, ICT in education, use of Open Science Resources, learn students to cooperate and act as researchers.
• Guidance for preparation: Search in literature, bibliography, internet and other sources, about ideas related to the geocentric and heliocentric model. Download Stellarium and SalsaJ. Both Stellarium and SalsaJ are free on internet. Access to archives providing images of Venus and the moons of Jupiter.
Pre-Experiment / Observation– Teaching Phase 1:Questions Eliciting Activities – PROVOKE CURIOSITY
Teacher introduces students to the geocentric model (Ptolemaic model). Teacher
can find useful information at:
http://en.wikipedia.org/wiki/Geocentric_model while he can show this educative animation
to students:
https://www.youtube.com/watch?v=wGjlT3XHb9A
Teacher ask students:
“How do they believe Venus should be shown from Earth according to the geocentric model?”
Teacher presents the following animation of Venus (geocentric model):
https://www.youtube.com/watch?v=OlnlbZHP-jk
According to the geocentric model can we see all phases of Venus?
Pre-Experiment / Observation– Teaching Phase 1:Questions Eliciting Activities – DEFINE QUESTIONS FROM CURRENT KNOWLEDGE
Are there moons on other planets?
According to the geocentric system can moons orbiting around other planets?
Students are asked to find information about the predominant cosmological systems in many ancient civilizations such as ancient Greece
including the noteworthy systems of Aristotle, Hipparchus and Ptolemy?
Teacher asks students to find information about the heliocentric
system of Aristarchus and Copernicus.
What was like the planetary system of Aristarchus?
Pre-Experiment / Observation– Teaching Phase 2: Active Investigation – PROPOSE PRELIMINARY EXPLANATION OR HYPOTHESES
December 1610You are now assistant at Galileo's Lab and
you receive a letter from former Galileo’s student Benedetto Castelli: If the position of Copernicus, that Venus
revolves around the sun, is true (as I believe), it is clear that it would necessarily sometimes be seen by us horned and sometimes not, even though the planet maintains the same position relative to the sun. Now I want to know from you if you, with the help of your marvelous glasses, have observed such a phenomenon, which will be, beyond doubt, a sure means to convince even the most obstinate mind. I also suspect a similar thing with Mars near the quadrature with the sun; I don't mean a horned or non-horned shape, but only a semicircular and a more full one.
Pre-Experiment / Observation– Teaching Phase 2: Active Investigation – PROPOSE PRELIMINARY EXPLANATION OR HYPOTHESES
December 1610
Let’ s observe the phases of Venus:
Students are asked to use the Stellarium software and set: Rome Italy as place and December 1610 as date.
Thus we can see the night sky as been seen from Galileo and of course his assistant.
Pre-Experiment / Observation– Teaching Phase 2: Active Investigation – PLAN AND CONDUCT SIMPLE INVESTIGATION
• After setting time, date and place, students are asked to locate Venus, according the following steps:
• Turn off atmosphere, ground and constellations.
• Search for Venus, using the search tool (F3).
• Center Venus on the screen (space bar).
• Zoom in.• Make time go faster ~ 6 times
• See how the phases change and try to find out the next new Venus and full Venus.
• See how the apparent size of Venus changes.
• Try to relate it to the difference in magnitudes.
• Venus is brighter in new phase than in full phase?
• Students are asked to record the magnitudes of Venus, in comparison to time and phases of Venus.
• What can we assume for the brightness of Venus?
Experiment / Observation– Teaching Phase 3: Creation – GATHER EVIDENCE FROM OBSERVATION
Time(Day/Month/Year) Phase of Venus Magnitude
1610/5/1 1 -3,551610/10/12 0,75 -3,91
1610/12/17 0,5 -4,38
1611/1/23 0,25 -4,32
1611/2/25 0 -0,07
1611/3/31 0,25 -4,23
1611/5/7 0,50 -4,26
1611/5/7 0,75 -3,87
1611/11/21 1 -3,58
Experiment / Observation– Teaching Phase 4: Discussion – EXPLANATION BASED ON EVIDENCE• Students are asked to explain the observed evidences
(experimental data). Do you believe that this observations are in accordance to the geocentric model?
• Venus forms all phases, or only meniscus?• How long will take Galileo to observe all Venus phases?
As Galileo’s assistant calculate the period of rotation of Venus, based on the image above and plot the magnitude of Venus in
accordance to its phases.
-1.5 -1 -0.5 0 0.5 1 1.5
-5-4.5
-4-3.5
-3-2.5
-2-1.5
-1-0.5
0
Λαμπρότητα ΑφροδίτηςΦάσεις Αφροδίτης
Μέγ
εθο
ς
Experiment / Observation– Teaching Phase 4: Discussion – CONSIDER OTHER EXPLANATIONS
Can we further evidence the heliocentric planetary model?
Galileo observed the moons of Jupiter. Those tiny light spots were orbiting around Jupiter appearing and disappearing in contrast to the steady stars.
Load Stellarium, search (F3) for Jupiter.
Center Jupiter on the screen (space) and zoom in.
Observe the moons of Jupiter.
Make time go faster ~4 times
Go back to 1610 and observe Jupiter as Galileo did.
Experiment / Observation– Teaching Phase 4: Discussion – CONSIDER OTHER EXPLANATIONSNow ask students to use SalsaJ, a free software for astronomical data processing. By using images taken by telescopes we can animate the
rotation of the moons around Jupiter.
Experiment / Observation– Teaching Phase 4: Discussion – CONSIDER OTHER EXPLANATIONS
The actions must taken by students are the following:• Load SalsaJ, a free software available on internet• From the “File” tab open images downloaded from internet available in
astronomical sites (NASA, ESA etc) preferable format .fts• Download a time sequence images.• From “Image” command tab select: “Stacks” and then “Images to
Stack”.• Continuously you can select: “Start animation” and view the video
created by real images, taken by telescopes.• If necessary apply some “Brightness and Contrast” corrections to the
images by the “Image” -> “Color” commands or by the button.
Post-Experiment / Observation– Teaching Phase 5:Reflection – COMMUNICATE EXPLANATION
Students can now argue about the heliocentric planetary model, but furthermore can explain how this was proved through observations.
As Galileo’s assistants can present true observation evidence and support their believes.
Of course the can respond to Benedetto Castelli’s letter with the following reply letter:
O how many consequences and ones of such import have I deduced, my Master Benedetto, from these and from my other observations. You almost made me laugh when you said that with these manifest observations the obstinate could be convinced. Well then, don't you know that to convince those capable of reason and anxious to know the truth the other demonstrations already produced were enough, but to convince the obstinate who care only for the empty applause of the stupid and dull crowd, the testimony of the stars themselves, come down to earth to discuss themselves, would not suffice? Let us then endeavour to learn something for ourselves and rest satisfied with this alone, but as for advancing ourselves in popular opinion or gaining the assent of philosophers in books, let us give up the desire and the hope.
• As follow up activities, students can observe through Stellarium the moons of other planet in our solar system.
Post-Experiment / Observation– Teaching Phase 5:Reflection – FOLLOW UP ACTIVITIES AND MATERIALS
• Furthermore students can search and download their own images from internet, process them and produce their own animation with SalsaJ, becoming researchers, after the experience as Galileo’s assistants.
Contact Information
• Name Surname: Chiotelis Ioannis• Affiliation: Model Experimental High School of
University of Patras• Address: Arakinthou 20, 26226, Patras, Greece• Telephone: +306948372341• Email: [email protected]