© 1999 ENSI (Evolution & the Nature of Science Institutes) www.indiana.edu/~ensiweb
This material may be copied only for noncommercial classroom teaching purposes, and only if this source is clearly cited.

 Return to Nature of Science List

 Return Home


Teaching Lesson



Testing Astrology


© 2002 by Larry Flammer



Realm and Limits

Science's Social Context


We now have a textbook for students on the nature of science. It's intended to replace, or supplement, the inadequate first chapter of your text. It's designed to coordinate and help sequence several of the nature of science (NOS) lessons on the ENSI site. It is targeted to students in any science class, grades 7-10 (or beyond). It helps to satisfy virtually all the new NOS standards in NGSS and Common Core. If you've used any of ENSI's NOS lessons, you already know how powerful they are. This new book addresses most of the common misconceptions about NOS. It also provides information about the differences between good science, poor science, and pseudoscience. It offers clues for recognizing those differences, and opportunities to practice using those clues. "What's this magic book I've been waiting for all my life?" It's called Science Surprises: Exploring the Nature of Science. "Tell me more - like where can I see this book?" Say no more. It's available as an eBook, published with Smashwords. Click Here to get more information and a link to sample (and purchase) the new eBook Science Surprises.



 Is astrology a science, pseudoscience, or a non-science? A major premise of astrology is that one's birth sign correlates with a particular collection of personality traits and interests. In order to test that premise, students compare their own traits with standard astrological descriptions, THEN learn whether their actual birthday matches the corresponding astrological dates. Simple statistical calculations reveal likely results due to chance. Discussion explores various explanations for results matching expectations for chance alone, and for results which do not match. The reasons that astrology is a pseudoscience are also examined.


 Science deals only with natural patterns and mechanisms.


Scientific explanations cannot include mysterious or supernatural forces, as such forces cannot be disproven.
Concepts whose proponents proclaim scientific support, yet do not survive scientific testing, are pseudosciences.
Astrology is a pseudoscience.
Astrology is unreliable, based on ancient mythology which defys modern knowledge, and is disproved by science.


   Students will....

1. recognize the elements of science vs non science and pseudoscience.
2. explain why astrology is a pseudoscience.

   CLICK HERE for PDF copies of materials

 Student Handouts:
Your Horoscope: Background, directions, and list of traits
Your Horoscope Worksheet: Discussion questions
Horoscope lesson (PDF version of this lesson)
Worksheet key
Overhead: Key to astrological signs and dates


 15-20 minutes minimum to a 50 minute period, depending on extent of discussion.


 See Materials




 Before using any of our Nature of Science lessons, be sure to read our General Background Information, with our Rationale and our Approach, and tips for Presenting the lessons for maximum effect and Dispelling some of the popular myths about science.

In any of the discussions expected with the class, select a few key items (important concepts) that lend themselves to interpretation, and introduce class to the Think-Pair-Share (TPS) routine dealing with those items. This is how "Active Learning" is done.

Also, take a look at the Horoscope PowerPoint prepared and kindly shared by ENSI-using teacher Nancy Power. You might find this helpful.

This lab is intended to show how unreliable horoscopes really are, and to not take them seriously.  Some people have claimed that “scientific studies” have supported their accuracy, but when critically examined (as this lab does),  we find that those descriptions fit no better than random chance.  Also, other studies have shown that there’s no way that the planets, and certainly the stars – and star arrangements (constellations) -  can in any way influence one’s personality or future by any known forces, on one's birthdate or any other point in time.  Apparently, those earlier studies (by astrologers) did not follow the rules of science, so horoscopes (and the astrology ideas behind them) should be thought of as a pseudoscience if followers say it's supported by science, or a non-science otherwise.  Also, before you finish this lesson, be sure that your students clearly know that astrology and astronomy are NOT the same thing. 

Astrology (not to be confused with the science of astronomy) claims that the personality, talents, daily activities, job choice, mate choice, and many other aspects of one's life are associated with that person's birthday. This is supposedly due to positions of the Sun, Moon and planets against the background of the visual star patterns (constellations) at the time and place of birth, and some mysterious force or influence between them. Those "positions" are their locations in the sky relative to one of twelve constellations arrayed along the ecliptic (general path of Sun/Moon and planets) throughout the year. Those twelve constellations are designated as the signs of the Zodiac, and whichever sign the Sun is "in" when you are born is your "Sun Sign". There are many other complex elements astrologers use to draw and interpret one's "horoscope", or birth map, but the Sun Sign under which you are born is considered the most important single factor, hence the question one might hear: "What is your sign?"

Many followers of astrology have claimed it as a "science", yet, for several reasons, it is best termed a pseudoscience. It is important, to be scientifically literate, that your students recognize what IS science, what is NOT science, and what is PSEUDOscience, and WHAT distinguishes these entities. The mysterious, forces which link these heavenly bodies with our birthdates behave like no other known forces. For example, unlike any other long-range forces, they are unaffected by distance. They are beyond nature, or "supernatural" forces, and astrologers make no effort to understand them. Furthermore, all attempts to demonstrate the purported association between birthdates and particular sets of traits, using scientific procedures, have failed. Nevertheless, many people (more than 50%) believe in astrology. As a "recreational" pastime, there's probably no harm here, but where astrology is used to make critical decisions about national security, personal health, and even choices of marriage and business partners (all of which happen regularly), it becomes a most serious issue. If students don't learn to recognize bogus science in their science classes, they probably never will.

NOTE: We provide two versions of this lesson:
1. Traditional sequence (T) of the signs, with main "key words" first in the list of traits
2. Randomized sequence (RS) of the signs, with those main "key words" buried in each list.
It might be interesting (and informative) to use one version in one class, and the other version in another. Try it, and let us know your results. Note that each "Background/Procedure/Table" page has its own Overhead Key.

Prepare copies of "Your Horoscope" handouts:
Page 1: Background, Procedure, and Table (one per person in your largest class, for re-use each period)
Page 2: Worksheet - Discussion Questions (one per person in all your classes

Prepare an overhead of the Key to the Sun-Sign Dates.

This lesson would be most appropriate as part of your Nature of Science unit. If used early in the unit, it could provide a stimulating example to explore the elements which distinguish science from non-science. If used later in the unit, it provides an opportunity for students to apply what they've learned about the nature of science: can they recognize an example of pseudoscience, and explain why it is a pseudoscience? Can they point out which rules of science are ignored or broken by astrology? Can they explain why it's a pseudoscience and not a non-science?

Some students might notice that the date-range for each Sun Sign may vary a day or so in different sources. If so, point out that this is due to factors e.g. leap year, time zones, daylight savings, latitude/longitude location, and when the ranges were quoted. The times used for this lesson were the ones most frequently quoted in several sources. Students born within a day or so of an adjacent sign are said to be on the "cusp" of their sign, which is usually factored in for a complete astrological chart. However, we will assume for the purposes of this lesson that such influences should cancel each other out, and not affect the class tallies appreciably.
The lists of traits and interests were also pooled and summarized from several sources; they seemed to show general consistency from source to source.




 See "Procedures" on the student handout.
1. Announce that we are going to do an experiment to test the accuracy and reliability of astrological birth signs.
The Question: are the Sun-Sign traits accurately associated with their respective birth-dates?
The Hypothesis: The traits associated with each sign correspond to the traits of those born under that sign
The Prediction: If this is true, then a significant proportion of us (greater than that due to chance) should find that our personality traits and interests do indeed match those described for our birth sign.
2. The Test: Hand out page 1 to all students; ask them to take out (or provide them with) a sheet of paper on which to place their birthday and the code number for the combination of traits with which they identify most closely.
3. Also, ask them to indicate whether they think astrology can give accurate information (YES) or not (NO).
4. Students fold their sheets in half, hiding their information, and hand them in when called for.
5. Teacher re-distributes the sheets so students do not get their own sheets
6. Show the KEY to Sun-Sign Dates on the overhead
7. Students indicate HIT or MISS on the sheet, based on the key.
8. Teacher takes show of hands tally of HITs and MISSes, and records on overhead or whiteboard.
9. Teacher also counts numbers of YESs and Nos (show of hands), and records on overhead or whiteboard.
10. Hand out Worksheet for students to work on by themselves (about 10 minutes)
11. When most have finished worksheet, engage class in discussion of their answers. You might want to ask groups of 2-4 students to engage in a preliminary discussion first, comparing notes and sharing ideas. Then have each group take turns in reporting out on each item, sharing and discussing replies classwide. See KEY for sample responses. If more HITs than expected, see item #1 in the Extensions & Variations.
12. Take new class consensus: Do you think astrology can give accurate predictions (YES) or not (NO)?




 1. Collect worksheets, and tally the YESs and Nos for item #12. Note how the class total compares with the original class total. Hopefully, there will be an increase in the NO answers, but don't be discouraged. Concepts are hard to change, whether they are logical or accurate or not. You might want to pose the question in a pre-test "attitude survey" at the beginning of the year, then again at the end of the year, to see if a combination of time, repeated experiences with the nature of science, and some growth in maturity have collectively raised the level of healthy skepticism and science literacy in your class.
2. Administer test questions in which students are asked to identify the elements of good science missing in astrology, and to recognize why it is a pseudoscience rather than a non-science enterprise. Carefully crafted multiple choice questions can also be used to assess this knowledge. If you do this, please share your efforts with us.



 1. It's quite possible, especially in some communities, that a fair number of students may know the traits assoicated with their birthdates (and their sign), so they may recognize them in the activity, producing a significantly higher number of HITs (over those expected due to chance). If this happens, be sure to point this out. You could even ask how many knew (or were even vaguely aware) of the traits for their birth sign. If not too many, subtract their responses from the class totals. This is also a good opportunity to discuss one of the pitfalls of such surveys: how many selected the traits expected, and how many selected the traits felt? If felt, to what extent could their traits be the result of a "self-fulfilling prophecy" situation, if they had been told or had read of their traits at an early age?
2. Several excellent suggestions for related activities are included in the Fraknoi article cited below.
3. Additional problems which might suggest particular inquiries can be found in the little book by Royer and the two online essays listed below.




 1. See the excellent article by Andrew Fraknoi in the Astronomical Society of the Pacific publication for teachers: The Universe in the Classroom, No. 11, Fall 1988. Original source-idea for this lesson. Available online at: <http://astrosociety.org/education/publications/tnl/11/11.html>. Lots of insights, teaching ideas, and resources.

2. One of the possible student projects suggested in the Fraknoi article is to compare the signs of a large number of people in a particular career (e.g. professional sports, or teaching, or business....) with their respective Sun Signs. Here's one of many online astrology sites, this one specializing in appropriate careers for different signs: <http://career.astrology.com/>. Try baseball players' birthdays.

3. Click here for the latest (3/2010) list of astrology-as-pseudoscience resources from Astronomer Andrew Fraknoi (along with many other psedudoscience resources).

4. Astrology Debunked
Comprehensive study of ‘time twins’ debunks astrology
The Washington Times, Sunday, August 17, 2003. Excerpt:
LONDON — Scientists have once and for all debunked astrology’s central claim — that our human characteristics are molded by the influence of the sun, moon and planets at the time of our birth — in the most thorough scientific study ever conducted on the subject.
For several decades, researchers tracked more than 2,000 people — most of them born within minutes of each other. According to astrology, the subjects should have had very similar traits.
The babies were originally recruited as part of a medical study begun in London in 1958 into how the circumstances of birth can affect future health. More than 2,000 babies born in early March that year were registered, and their development was monitored at regular intervals.
Researchers looked at more than 100 different characteristics, including occupation, anxiety levels, marital status, aggressiveness, sociability, IQ levels and ability in art, sports, mathematics and reading — all of which astrologers claim can be gauged from birth charts.
The scientists failed to find any evidence of similarities between the “time twins,” however. They reported in the current issue of the Journal of Consciousness Studies: “The test conditions could hardly have been more conducive to success … but the results are uniformly negative.”

5. Dean, Geoffrey A., et al. 1985. The Guardian Astrology Study: A Critique and Reanalysis. The Skeptical Inquirer, vol.9, no.4, Summer 1985, pp. 327-338. Results and analysis of massive study of sun signs and occupations in Britain. Includes list of sun signs and the occupations likely to be associated with each sign.

6. Bob, Murray L. 1988. The Stars Smile on Soothsayers: The Secret of Reagan's Success. The Skeptical Inquirer, vol.13, no.1, Fall 1988, pp. 7-9. Nice summary of why daily horoscopes seem so "right" so often. Part of a suite of short articles by various authors of the influence of astrology on politics, mainly Nancy Reagan's dependence on astrologers for every aspect of the President's schedule.

7. Royer, Mary-Paige. 1991. Astrology: Great Mysteries - Opposing Viewpoints. Very nice overview of astrology, along with many of the challenges to its validity, done in a relatively non-confrontational manner. This little book should be in your school or classroom library.

8. Jerome, Lawrence E. 1977. Astrology Disproved. Prometheus Books.

9. Essay: Critical Thinking: Astrology as a Pseudoscience.

10. Essay: Astrology, from the Skeptic's Dictionary:

11. Astrology Update: An excellent and convenient resource on astrology can be found on the Center for Inquiry (CSI) website at http://www.csicop.org/si/show/does_astrology_need_to_be_true_a_thirty-year_update
The article "Does Astrology Need  to Be True? A Thirty Year Update" by Geoffrey Dean appeared in the July/August 2016 issue of the Skeptical Inquirer magazine, pp. 38-45.

12. Science Denial: In that same issue (and also available on the CSI website) is the article "A Skeptical Response to Science Denial" by John Cook <http://www.csicop.org/si/show/a_skeptical_response_to_science_denial>. The author points out "Science denial has significant consequences. AIDS denial caused over 300,000 deaths in South Africa. Vaccination denial has allowed preventable diseases to make a comeback. Climate science denial helped delay sorely needed mitigation policies, committing us to direr climate impacts for decades to come." (Emphasis added).


Some of the ideas in this lesson may have been adapted from earlier, unacknowledged sources without our knowledge. If the reader believes this to be the case, please let us know, and appropriate corrections will be made. Thanks.

This lesson is adapted directly from one of the teaching ideas in the Fraknoi article cited above. However, instead of using the terribly vague comments found in a typical daily horoscope, as suggested, we have chosen to use a general consensus of descriptive traits typically associated with each sign. Whereas the original (Fraknoi) version has been successfully used in the classroom, the present version has not. Therefore, we welcome feedback from your experience with this material.

Developed and adapted for the ENSI site by Larry Flammer, November 2002.

 Return to Top of Page


 Return to List of Lessons