Informative Speech: Your goal for this speech is to raise the level of knowledge of your audience about an object, concept, person, policy, place, event, or process. Your topic must relate to your Broward College Pathway.This speech will teach you how to speak from note cards. A full-sentence outline with a bibliography are required for this speech. The speech must be 4-6 minutes in length. Points are deducted for going under or over this time limit. Three sources or reference material are required for this speech. You must use supporting material linked to the thesis and material that enhances your credibility as a speaker and the clarity of the topic. Sources and reference material are orally cited by you during the body of the presentation. Main points of the speech should be amply supported by specific research. Research must consist of sufficient variety (statistics, examples, comparisons, quotations, etc.).
This speech will be recorded and the link will be uploaded into the Discussion area using YouTube.
Recorded speeches do not require an audience. The speech recording must be uploaded into the discussion area in D2L. Your recording must be recorded with you standing. You should record yourself from your knees up to the top of your head. The professor needs to see your body gestures and posture. Do not edit the recording or turn the recorder off once you start recording.
All presentations will be extemporaneously (conversationally) delivered. Reading or memorizing a presentation will result in failing the assignment. However, you will be permitted to use no more than 5 3X5 or 4X6 inch speaker cards with key words on them while you speak. Points are deducted for going under or over this time limit.
Revised – 6/8/2020 The Lens Equation – 1
THE LENS EQUATION
Purpose
To study the central idea of the science of optics, the lens equation.
Introduction
In astronomy, we observe objects with light since the distances are so large. With the light we must combine
the other senses of taste, touch, smell, hearing, and seeing. In order to do this, we must manipulate the
light. We do this by allowing the light to enter a denser (i.e. a liquid or solid) object or being bounced off
the same object. The two processes are called refraction and reflection, respectively. We use lenses made
of glass to refract light and mirrors to reflect light. They both focus light onto one point and obey a single
equation called the lens equation. In this lab, we will focus on the convex lens, the optical system that most
telescopes use this type of lens or its complimentary system the concave mirror system. The convex lens
works like this:
where the object is focus into an image on the other side of the lens. The formula to determine the focal
length of the lens is:
DistanceImage
1
DistanceObject
1
LengthFocal
1
+= Equation 1
For optical systems we also want to know about the magnification of the images. We want to see how we
can manipulate the different images. We can determine this from the ratio of the object size to the image
the lens creates. Or we can determine this from the ratio of the object distance to the image distance at the
position of the lens creating that image size. The geometry is as follows:
Distance Object
Distance ImageRatio DistanceionMagnificat
Size Object
Size Image
=== Equation 2
Object Size
Image Size
Revised – 6/8/2020 The Lens Equation – 2
Procedure
1. Open https://ophysics.com/l12.html. This is the opening screen:
2. Move the focus point show that it shows f = 2 by clicking that focal point. Now make sure
the object is size 2 and it is three squares away from the focal point. Record the object
distance, image distance, and absolute value of image height in Table 1. Do this for four
other object positions.
3. Move the focal point to f =4 and repeat the procedure from step 2.
4. Now complete Table 3 based on the data from Tables 1 and 2.
https://ophysics.com/l12.html
Revised – 6/8/2020 The Lens Equation – 3
Data Sheet Laboratory 2
Table 1 f = 2, ho = 2
Object
Distance
Image
Distance
Image
Size
1/Object
Distance
1/Image
Distance
1/
Focal
Length
Table 2 f = 4, ho = 2
Object
Distance
Image
Distance
Image
Size
1/Object
Distance
1/Image
Distance
1/
Focal
Length
Table 3 Magnifications and Distance Ratio
f= 2:
For the Smallest Image Size: Magnification = Image Size/Object Size = ____/____ =
Distance Ratio = I/O = ____/______=
For the Largest Image Size: Magnification = Image Size/Object Size = ____/____ =
Distance Ratio = I/O = ____/______=
f = 4:
For the Smallest Image Size: Magnification = Image Size/Object Size = ____/____ =
Distance Ratio = I/O = ____/______=
For the Largest Image Size: Magnification = Image Size/Object Size = ____/____ =
Distance Ratio = I/O = ____/______=
Revised – 6/8/2020 The Lens Equation – 4
Questions
1. Mirrors tend to be lighter than the equivalent lenses. If you were developing a telescope that
would need to collect light from a dim source, would you use a lens, multiple lenses, a mirror, or
multiple mirrors to build the telescope? Defend your answer using your data and telescope
simulators from the internet.
2. Can we use the distance ratios to find the magnifications? Analyze our understanding of lens
characterization.
3. Analyze the shape of the lens with respect to focal length.
Revised – 5/13/2020 1.1
THE CELESTIAL SPHERE
Equipment
Star chart, skyviewcafe.com
Purpose
The purpose of the lab is to understand the motion and position of the stars, Sun, and
planets using the celestial globe.
Introduction
From the earliest times, we have studied the stars. In our minds we have created
models of how the universe worked. We created patterns out the motion and locations of the
stars, Sun, and planets. The apparent patterns we have created in location of the stars are
called constellations. Throughout time, we have mapped the constellations in star charts.
From these star charts, we can plot the motion of the stars, Sun, and planets. The stars have
three motions; diurnal (daily) motion, annual motion, and precession. The daily motion is
due the Earth rotating on its axis. The annual motion is due to the Earth orbiting the Sun.
And precession is caused by the Earth wobbling on its axis. As the Earth is tilted on its axis,
the Sun’s motion in the sky is more complex than stellar motion as it rises and sets in different
positions in the sky each day. The most complex motions are the planetary motions as they
co-revolve around the Sun along with the Earth.
We can use a celestial globe to explore the sky. The globe is a smaller translucent
globe with stars printed on the sky along with the lines of right ascension and parallels of
declination; the coordinates of longitude and latitude in the celestial sphere, respectively. We
can move the sphere to simulate the motion of the stars in the sky throughout the night and
the year to explore diurnal and annual motion. Also, we can adjust the tilt of the globe to visit
different locations on the Earth as to observe how the sky appears at these locations.
In this lab, we will use the aforementioned two special tools in astronomy. We will
visit the planetarium and confirm the results with the celestial sphere in the laboratory. We
will observe the motion of the different motions of the stars, planets, and the Sun in the
planetarium. Following up in the laboratory, then we will recreate the motions on the celestial
globe.
Revised – 5/13/2020 1.2
Procedure 1: Locating Objects on the Globe
1. Open skyview.com on your browser. Figure 1 shows the entry page. Note how to
change the date/times and locations on the earth. Note 12 noon is local noon and the
Sun rises on eastern horizon and sets on western horizon.
Figure 1 Skyview Cafe Webpage. You can click on any star to see the
altitude/azimuth and right ascension/declination.
2. Now find the objects or coordinates indicated in Table 1 and list their right
ascension/declination or their names in Table 1 using your star chart or the website.
3. Now note the presences of a wave-like line surrounding the equator; this is the ecliptic,
the Sun’s path around the sky during the year. Now click Celestial and Ecliptic Grid to
guide you which constellation the Sun is located on the dates listed in Table 1. Record
these constellations in Table 1.
Procedure 2: The Sun’s Motion and the Visibility of Stars
1. Now we are going to set the globe for our location on the Earth. We need to set the
correct inclination for our sky view. We do this by determining the co-latitude. We do
this set the correct altitude of the North Star. Please find our location by setting either
26◦ North or finding Davie in the location box. And set the dates for 2020 in the
dates/time box as indicated in Figure 1.
2. Using the date/time box, set the sun to June 21. Now click on the hour in the date/time
box and then use the up and down arrows move the Sun from sunrise to sunset; count
the number of hours from sunrise to sunset and record in Table 2. Also record the
Revised – 5/13/2020 1.3
azimuth at sunrise and sunset for each date by clicking on the Sun. Repeat for the
December 21.
3. Now set the Sun for Noon by setting the time for 12:00 noon. Please find the altitude
for the noon sun for June 21. Set the website for 50 degrees using the co-latitude and
find the altitude for the noon sun. Do this for 90 degrees. Repeat these for December
21. Record these altitudes for the latitudes in Table 2. Set the Sun for Midnight
(00:00) on these dates and record which stars that are listed in Table 1 in Table 2.
Revised – 5/13/2020 1.4
Table 1 Procedure 1: Locating Objects on the Globe
1) Please find these four stars in these constellations and list their right ascension and
declination:
Constellation Star Right Ascension Declination
Bootes Arcturus
Gemini Castor
Ursa Minor Polaris
Scorpio Antares
2) Please list and find the different stars/constellation and for these right ascensions
and declinations:
Right Ascension Declination Star Constellation
6 Hr 45 Min -19◦
18 Hr 40 Min +39◦
5 Hr 15 Min +46◦
3) What constellations in the Sun located for each date?
Date Constellation Horoscope Constellation
March 21 Ares
June 21 Cancer
September 21 Virgo
December 4 Sagittarius
December 21 Sagittarius
Revised – 5/13/2020 1.5
Table 2 Procedure 2: The Sun’s Motion and the Visibility of Stars
1) What are number of hours in the day for June 21? December 21? And the
azimuths of sunrise and sunset? The altitude of the noon Sun? The stars are visible
at midnight?
Date For 26 degrees For 50 degrees For 90 degrees
June 21 Hours _____
Sunrise _____
Sunset ______
Altitude _____
Stars Visible:
Hours _____
Sunrise _____
Sunset ______
Altitude ______
Stars Visible:
Hours _____
Sunrise _____
Sunset ______
Altitude _____
Stars Visible:
December 21 Hours _____
Sunrise _____
Sunset ______
Altitude _____
Stars Visible:
Hours _____
Sunrise _____
Sunset ______
Altitude ______
Stars Visible:
Hours _____
Sunrise _____
Sunset ______
Altitude _____
Stars Visible:
Revised – 5/13/2020 1.6
Questions:
1) Explain and analyze the possible shift of the Sun with respect to the stars.
2) Analyze the motion and position of the Sun at the different latitudes and times of
the year.
3) Looking the visibility of the stars, evaluate which location would be good for an
observatory.
4) Comment on which device, star chart or celestial globe, would be better to use
for observing with a telescope.
Spectra- 1
SPECTRA LAB
Purpose: To study spectra and see how they relate stars and planets.
Introduction:
Spectrums are created by the emission and absorption of a photon of light by electrons surrounding
the nucleus of the atom.
When the photon is emitted we see separate spectra lines. When the photon is
absorbed we see the continuum spectra blotted out by the black spectra lines. Each element has its own
spectrum, a type of fingerprint, due to the fact each element has a differing number of electrons that can
absorb or emit photons. Figure 1 shows each process.
Figure 1 A model of the Bohr atom.
http://v.d.singleton.home.att.net/genchem/spectra.gif
Figure 2 Absorption and Emission Spectra of Hydrogen
http://www.astronomynotes.com/light/s5.htm
In astronomy we only observe objects from a distance. But in order to experience these objects we
need to detect the items with our five senses; sight, smell, hear, touch, and taste. We design robotic probes
and telescopes to do this, but they must be able to combine all those senses into one, sight. We do this
through the science and art of spectroscopy. From one spectrum we can see, smell, touch, hear, and taste
a planet or star.
We start with sight. By combining the colors of a spectrum, we can see the color of the planet or
star that we are observing. It is like when we combined the colors of paint when we were in art class.
Second each spectrum is a fingerprint of an element and by detecting the different elements that make up
http://v.d.singleton.home.att.net/genchem/spectra.gif
http://www.astronomynotes.com/light/s5.htm
Spectra – 2
a planet we can smell the planet. Just like we associate greens and browns with earthy smells while we feel
blues are fresh and clean like the fallen snow. We can touch the planet from the intensity of the spectral
lines. If they are bright or big they indicate a hot source while a smaller or dim line indicates a cooler object.
The color of the source is a collaborating observation. If there are more red lines, we observe that the source
is cooler. If the source is bluer, the source is hotter. Finally, if the lines waver from image to image, we see
that the planet or star is undergoing change like a planet or star quake. We can tell all this from a spectrum.
Below you see the electromagnetic spectrum, we see that light is much broader from what we see
through our eyes. It includes the radio to the gamma-ray regions with the optical being a small part of the
whole spectrum.
Figure 3 the Electromagnetic Spectrum
http://www.lbl.gov/MicroWorlds/ALSTool/EMSpec
Now we compare the visible to the solar spectrum. We notice it seems that the spectrum has lines
taken out of the continuum. That is because of amount of gas and dusts that surround the hot core of the
sun absorbs the light coming from the core. Also one notices that certain wavelengths are brighter. Wien’s
Law explains that the bluer the star, the hotter the star. Notice in the Sun, we see it is a middle of a road
star with the brightest color being yellow. We use the spectra to determine color, temperature, and
composition.
http://www.lbl.gov/MicroWorlds/ALSTool/EMSpec
Spectra – 3
Figure 4 the Solar Spectrum
http://www.pbs.org/wgbh/nova/teachers/activities/pdf/3113_origins_01
Back in 1900’s, an astronomer called Annie Jump Cannon looked at the different spectra of stars.
She categorized them by the presence of lines with in each star’s spectra. She categorized them by less
lines going to more lines. The stellar types were called by O, B, A, F, G, K, M. They are shown in the Figure
6 below.
Figure 5 the Stellar Spectral types
http://blueox.uoregon.edu/~courses/BrauImages/Chap17/FG17_010
Finally, in the 1930’s two astronomers called Hertzsprung and Russel independently studied the
temperature of stars versus the brightness of each of the stars. They came to same American Astronomical
Society meeting and presented the same graph. This graph shows the life stages of the star going from
proto-star, main-sequence, and red giant phase, to death as you can see in Figure 7 below.
http://www.pbs.org/wgbh/nova/teachers/activities/pdf/3113_origins_01
http://blueox.uoregon.edu/%7Ecourses/BrauImages/Chap17/FG17_010
Spectra – 4
Figure 6 the H-R Diagram
http://www.aw-bc.com/info/bennett/images/hrdiagram
http://www.aw-bc.com/info/bennett/images/hrdiagram
Spectra – 5
Part I: Elemental Spectra
1) After obtaining a diffraction grating from your instructor, construct the shoebox spectrometer
according to the image below:
Figure 7 Shoebox Spectrometer
https://www.uq.edu.au/_School_Science_Lessons/36.101.GIF
2) Open up https://www.ifa.hawaii.edu/~barnes/ASTR110L_F05/spectralab.html. Look at the spectra
about mid page and enter the name, atomic number (see
https://en.wikipedia.org/wiki/Periodic_table), and check mark the color of the lines present in Table
1.
3) Please take an image of one of the spectra through your box using your camera on your cellphone
of one light source around where you live (DO NOT LOOK AT THE SUN!).
Part II: Stellar Spectra
1) Open http://skyserver.sdss.org/dr16/en/proj/advanced/spectraltypes/lines.aspx. Read the page on
how we look at the stellar spectra and try to type the example stellar spectra for the correct type.
Click “Next” at the bottom of the page.
2) On the next page is a list of stars with unknown spectral types. Click on the second column for each
star and you will receive the following screen:
https://www.uq.edu.au/_School_Science_Lessons/36.101.GIF
https://www.ifa.hawaii.edu/%7Ebarnes/ASTR110L_F05/spectralab.html
https://en.wikipedia.org/wiki/Periodic_table
http://skyserver.sdss.org/dr16/en/proj/advanced/spectraltypes/lines.aspx
Spectra – 6
3) Please enter the name on Table 2, note the color of the star in the image, and click on the spectra
to zoom in on the spectra. Using the information from the website and Figure 6 determine the
spectral type and enter this into Table 2. The dark lines in Figure 6 represent absorption lines like
the one indicated above.
Part III: Hertzsprung and Russel Diagram
1) Graph the absolute magnitude (y-axis) versus the temperature (x-axis) using the data from Table 3
using Excel or similar program. Enter temperature under column A and absolute magnitude under
column B. Select both and under Insert >> Chart like this:
Spectra – 7
2) Once you insert the chart, right click on both the x-axis and y-axis and select “Format Axis” and click
on “Maximum Axis Value” and “Values in Reverse Order” like this:
3) Include this worksheet in your laboratory report.
Spectra – 8
Data Sheet Laboratory 3
Table 1 The Spectral Colors of Particular Element
Element
Name
Atomic
Number
Red Orange Yellow Green Blue Violet
Table 2 Stellar Spectral Types
Object Name Color Spectral Type
Table 3 Stellar
s for brightest stars visible from the Northern Hemisphere
Common Name Temperature
Sun 5800 4.8
Sirius 9600 1.4
Canopus 7600 -2.5
Rigil Kentaurus 5800 4.4
Arcturus 4700 0.2
Vega 9900 0.6
Capella 5700 0.4
Rigel 11,000 -8.1
Procyon 6600 2.6
Achernar 22,000 -1.3
Betelgeuse 3300 -7.2
Hadar 25,000 -4.4
Acrux 26,000 -4.6
Altair 8100 2.3
Aldebaran 4100 -0.3
Antares 3300 -5.2
Spica 2600 -3.2
Pollux 4900 0.7
http://www.astro.indiana.edu/catyp/activities/near_bright
http://www.astro.indiana.edu/catyp/activities/near_bright
Spectra – 9
Questions
1) Note the relationship between the number of spectral lines and atomic number. In the stellar spectra,
note the number of spectral lines and temperature and the color of the star.
2) Note any patterns in the Absolute Magnitude versus Temperature plot. Compare to the Hertzsprung-
Russel diagram (Figure 7 in the Introduction) from above and classify these outlier stars.
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