How do our Students Identify Expertise?

“Ignorance more frequently begets confidence than does knowledge: it is those who know little, not those who know much, who so positively assert that this or that problem will never be solved by science.”
Charles Darwin

When can you use a title?  What makes someone an expert?  Over the years, I have built several pieces of furniture, tables, bookshelves, and chests does that make me a master carpenter?  I have met several master carpenters and seen their work; I am most definitely not a master carpenter.  Using the book Make Your Own Ukulele: The Essential Guide to Building, Tuning, and Learning to Play the Uke, I’ve built two ukuleles.  While the author of the books says once you’ve made “a professional-grade ukulele” you are a luthier I don’t think I will be calling myself a luthier anytime soon.

I have a lot of “hobbies,” I have made knives, braided whips, bound books, made hard cider, and cooked more things that I can remember.  The only one of my hobbies that I might be willing to use a title for is photography.  I have been practicing outdoor and nature photography for 30+ years, and if you caught me in the right mood, I might call myself a photographer.  What makes photography different? It’s not the time I have put into it, though I have long past the 10,000-hour mark.  I’ve had my work reviewed and excepted by people in the field, not every picture but enough to be comfortable with my skill.

I am selective when it comes to titles and proclaiming my expertise. However, there are people that are not selective about their expertise.  Believing your knowledge to be greater than it is, is common enough to have a name the Dunning–Kruger effect.  However, an even bigger problem than an individual mistaking their knowledge is when an individual mistakes their knowledge and present themselves as an expert.

The internet and self-publishing have increased our access to knowledge and different points of view.  Previously it was simply not possible, for multiple reasons, to publish everything, so editors and review boards had to decide what to publish.

While the benefits to open publications are significant, we must ask without “gatekeepers” how do we identify expertise?  Many people may ask, “why do we care?”  Well, we have issues like GMOs, STEM cell therapy, cloning, genetically engineered humans, and technology we have not even thought of yet.  How will people decide what to do with these technologies if they can’t identify expertise?

A great example of this is a recent study on GMO’s Those who oppose GMO’s know the least about them — but believe they know more than experts.  In the study, most people said that GMOs are unsafe to eat, which differs from scientist where the majority say GMOs are safe.  People’s views of GMOs are not a surprise news coverage of GMO clearly shows how people feel.  The interesting thing was the second point covered in the study.  The people that were most opposed to GMOs thought they knew the most about them.  However, when this group of self-identified experts had their scientific knowledge tested, they scored the lowest.

The difference between people’s beliefs and actual knowledge gets even more complicated when we move beyond GMOs.  While the consensus is that GMOs are safe and could be beneficial, their loss isn’t instantly deadly.  After all, we haven’t developed that GMO that will grow in any condition and solve world hunger or capture all the excess CO2 from the atmosphere.  However, what about the Anti-vaccination movement?  I’m not going to get into all the reasons people think they shouldn’t get vaccinated. However, let’s talk about how their action will affect you.

I know a lot of people say it’s just a small percentage and I’ve been vaccinated so ignore it.  You may even be one of them, let me ask you to have you heard about things like efficacy and herd immunity?  Additionally, do you remember or know that the measles can kill? Let’s look at the numbers, according to the CDC; the Measles vaccine is 93% effective.  Using the recommended two doses, 3 out of every 100 people that are vaccinated can get the measles.  Even if everyone in the US were vaccinated, there would be 9.8 million people still susceptible to measles.

A lot of people don’t believe this; after all, we don’t see millions of measles cases every year.  Herd immunity (community immunity) is the reason we don’t see millions of cases.  The idea is if enough people in a community are immunized, illness can’t spread through the community. So even if you are one of the individuals were the vaccine was ineffective, you don’t catch the disease because the individuals around you have an effective immunization.

What percentage of vaccination against measles grants herd immunity?   According to a presentation by Dr. Sebastian Funk Critical immunity thresholds for measles elimination for herd immunity to work for measles, the population needs an immunization level of 93-95%.  According to the CDC, the percentage of individuals 19-35 months is 91.1% while the percentage of individuals 13-17 years old is 90.2%. That is below the level needed for herd immunity.  Therefore, individuals choosing not to get vaccinated are endangering, not just themselves but others.

Fortunately, we know individuals can learn earlier this year Ethan Lindenberger, an 18-year-old teen that got himself vaccinated against his anti-vaccination mother’s wishes testified before congress about how he made the decision. A lot of what he talked about was reading information from credible sources and real experts.

So how do we teach students to identify credible experts and valid information?  I have heard a lot of faculty say identifying reliable experts is easy. You look at who they are and where they work.  Well, it’s not quite that easy; for example, Andrew Wakefield was a gastroenterologist and a member of the UK medical register and published researcher.  He claimed that the MMR vaccine was causing bowel disease and autism.  After his research was shown to be irreproducible and likely biased and fraudulent, the general medical council removed him from the UK medical register.  However, he continues to promote anti-vaccine ideas.

We need a better approach than where they work.  Dr. David Murphy suggests we interrogate potential experts using the tools of the legal system interrogation and confrontation. Gary Klein suggests a list of seven criteria;

  1. Successful performance—measurable track record of making good decisions in the past.
  2. Peer respect.
  3. Career—number of years performing the task.
  4. Quality of tacit knowledge, such as mental models.
  5. Reliability.
  6. Credentials—licensing or certification of achieving professional standards.
  7. Reflection.

While none of these criteria are guarantees individually taken as a whole, they can give a functional assessment of expertise.  However, we don’t often interview every individual we encounter in research. A third and likely most applicable approach involves reading critically and fact-checking.  To quote a phrase, “we need to teach students to question everything.”

One approach is the CRAAP test (Currency, Relevance, Authority, Accuracy, and Purpose) developed by Sarah Blakeslee of California State University, Chico.  The CRAAP Test is a list of questions that the reader can apply to a source of information to help determine if the information is valid and accurate.  The questions for Currency are:

  • When was the information published or posted?
  • Has the information been revised or updated?
  • Does your topic require current information, or will older sources work as well?
  • Are the links functional?

The currency questions address the age of the information.  Each section of the CRAAP test has 4 – 6 questions. The idea behind the CRAAP test is that once the researcher/student answers all the questions, they will be able to determine if the information is good or bad.

As an alternative or perhaps compliment, we should be teaching our student to think and behave like fact-checkers.  One of the most compelling arguments about fact-checkers comes from the book Why Learn History (When It’s Already on Your Phone)by Sam Wineburg.  In chapter 7: Why Google Can’t Save Us, the author talks about a study where Historians (average age 47) from several four-year institutions were asked to compare information about bullying on two sites. A long-standing professional medical organization maintains one site. While a small splinter group maintains the other (the issues that caused the split was adoption by same-sex couples).  A group of professional fact-checkers also examined the two sites.

Many of the professional histories decided that the splinter group was the more reliable source of information.  In contrast, the fact-checkers decided that the original organization was the most reliable.  The difference between the two groups is what the author calls vertical (historians) versus lateral (fact-checkers) reading.  The historians tend to read down the page and look at internal information.  The fact-checkers jump around and leave the page to check additional information like where these two organizations came from, what others write about them, and what other groups and individuals say about the same questions.

The way information is published and disseminated has changed and will likely continue to change as the tools become easier to use and cheaper.  Education needs to change how we teach our student to evaluate information.  I think I will argue for a bit of lateral thinking.

Thanks for Listing to My Musings
The Teaching Cyborg

Writing, Chances Are You Are Doing It Wrong

“You can always edit a bad page. You can’t edit a blank page.”
Jodi Picoult

Writing is a central component of education.  We could argue that writing is the ultimate goal of higher education.  After all, the final project of an academic student is the writing and acceptance of the dissertation.  Even during undergraduate education, there is a lot of focus on writing.  Most undergraduate classes have at least one or two multipage writing assignments.  With all this focus on writing the US should be turning out the greatest writers in the world.

However, there are a lot of essays saying college graduates can’t write.  In $100K, You Would At Least Think That College Grads Could Write from the Forbes website, the author states “They (students) take lots of courses and study lots of stuff (or at least seem to), but don’t even learn how to use the English language well.”  Many others agree that students don’t learn to write.  “I didn’t say the ugly truth: that her bright boy might not graduate as a solid writer, no matter how good the college.” (Maguire)

In the book Academically Adrift Limited Learning on College Campuses the authors state “At least 45 percent of students in our sample did not demonstrate any statistically significant improvement in CLA performance during the first two years of college.” (Arum and Roksa 2011, 204) The CLA uses open-ended questions to test critical thinking, analytic reasoning, problem-solving, and written communication.  According to this study, almost half of all students show no improvement in writing ability after two years.

Outside of higher education, we see similar views.  George Leef starts his post on writing by saying, “One of the loudest complaints about college graduates once they enter the workforce is that they can’t write well.” (Leef, George. “Why So Few College Students Can Write Well.” National Review. retrieved August 24, 2019, from https://www.nationalreview.com/corner/college-students-cant-write-well/) In his essay for education week, Marc Trucker states, “My organization decided a few weeks back that we needed to hire a new professional staff person.  We had close to 500 applicants. Since the task was to help us communicate information related to the work we do, we gave each of the candidates one of the reports we published last year and asked them to produce a one-page summary.  All were college graduates.  Only one could produce a satisfactory summary.  That person got the job.” (Trucker, 2017)

How did we get to this point were college graduates can’t write?  There are multiple issues that impact a student’s ability to write.  I have demonstrated one of the problems in paragraphs 2-4 of this blog post.  Can you identify it?  I will give you a hint.  In her article for Inside Higher Ed, Jennie Young talks about the problems that face the mostly adjunct Instructors (or graduate students) that teach the writing courses.  Based on the course load, these instructors carry, it is almost imposable to address all the problems in all the essays they need to grade. As she says, “Naturally, you begin looking for the easiest way to whittle down your load — some way to count some papers “in” and move others out of the way. And now imagine that just within your reach is the low-hanging fruit of MLA format (or APA, or Chicago or whatever).”  The title of the article is The Weaponization of Academic Citation.

Grading on style is easy, quick, and unambiguous.  The style manuals create the rubric. You can point to the rule or rules and say you didn’t follow the rules, and they are the base requirement.  Well, I followed the rules in paragraphs 2-4 of my blog; what do you think?  Actually, I followed five sets of rules (I will let you figure out which styles I used). 

I have written more than 54,000 words on my blog to this point.  I often conduct research when writing my posts.  However, I don’t follow a rigged citation or writing style. I use what feels right.  I want my readers to be able to find the works I’m referencing if they wish to, but my focus is on the thoughts and arguments I’m writing.  Would it improve my writing and arguments if I rigidly followed a style?  I guess you will have to tell me.  I do know that no style no matter how rigidly followed will correct incoherence.

Another issue with students writing abilities is the field of study.  I have had the opportunity to work with students, faculty, and administrators in many different disciplines.  What I have discovered over the years is how varied fields can be.  After all, a written critique of a new painting in the modernist style is not going to be like a research report describing a new and improved method to synthesize an organic compound.

Even within a single discipline thing can get confusing.  If you are in a field were publication is primarily through Journals articles well it seems each journal has its own rules and style guides.  If your field publishes books, it seems each publishing house has different requirements.

With all these differences between fields, publishers, and even writing styles the truth of the matter is that no matter how you write from someone’s point of view your essay, manuscript, or journal article is miswritten.  It’s a lot like the answer to the question Is hell Exothermic or Endothermic, “Some of these religions state that if you are not a member of their religion, you will go to Hell. Since there are more than one of these religions and since people do not belong to more than one religion, we can project that all people and all souls go to Hell.”  Concerning writing, we could say, since every group or field has a correct way of writing, and the author can only write in one method, all writing is incorrect.

While the previous statement is an exaggeration, it is not entirely incorrect.  But I think it leads to a more critical question. At the undergraduate level, what are we trying to teach the students when it comes to writing?  What’s more important in an introductory writing class learning to construct well thought out and coherent sentences or committing to memory the proper position of every comma and period for your citations in the MLA, APA, and Chicago styles.

To reference Einstein, “why would I waste my time memorizing something I can look up in a book.”   At least for the undergraduates writing should focus on good writing, not styles.  There are tools like Zotero that will format citations and create bibliography correctly in whatever style your publisher wants.  Additionally, citation software can keep your citation style up to date without you having to thoroughly read through each new addition of a style guide looking for changes.

Yes, teaching students to write well is hard.  Much harder than taking the easy way out and quickly grading papers on incorrect styles, page lengths, and formatting.  However, no amount of style and proper formatting will save an essay from incoherent sentences and poorly constructed paragraphs. At the undergraduate level, the bulk of the focus should be on good writing.  Sometimes I think we forget that undergraduate majors don’t follow a single path.  I know students that have earned a BA in Spanish language that have gone on to pursue cares in Law, International Business, Medicine, or Professorships.  I often think the push towards specialization in undergraduate education has come at the cost of general education.

Ask yourself when you are developing an undergraduate writing assignment is that assignment helping the students learn to write? Or is it teaching them structure without substance? In the meantime, I think I will continue “citing” information in my blog based on what feels right.

Thanks for Listing to My Musings
The Teaching Cyborg

Reference

Arum, Richard, and Josipa Roksa. 2011. Academically adrift: limited learning on college campuses. Chicago: University of Chicago Press.

Maguire, John. “Why Many College Students Never Learn How to Write Sentences.” The James G. Martin Center for Academic Renewal, 1 APR 2016, https://www.jamesgmartin.center/2016/04/why-many-college-students-never-learn-how-to-write-sentences/

Trucker, M. (2017). Our Students Can’t Write Very Well—It’s No Mystery Why Retrieved from http://blogs.edweek.org/edweek/top_performers/2017/01/our_students_cant_write_very_wellits_no_mystery_why.html 

Teaching Sciences: Where Should We Start

“Chemistry ought to be not for chemists alone.”
Miguel de Unamuno

Recently a video showed up on LinkedIn.  The video was a demonstration of an Augmented Reality (AR) app The Atom Visualizer made by Machine HaloThe Atom Visualizer is the first ARCore app.  In the LinkedIn demo video, the app functions with chemistry flash cards.  The demo is not the first AR flashcards several already exist, like AR Flashcards and AR Talking Cards, to name a couple.  The Atom Visualizer is the first app to use Google’s AR framework ARCore.

While there is a lot to discuss with respects to AR and education, one person compared it to televisions and said it therefor would never work.  Another talked about problems with implementation.  However, I might talk about these issues another time.  What stood out to me as I looked over the comments were comments about chemistry and education.

S., A.
“I am glad to see something like this, but unfortunately this is sending a wrong note. For ex: Oxygen is never O, it is O2 & 2 atoms of Hydrogen combine with 1 O2 atom to form H2O Sodium as Na doesn’t react with Chlorine directly, it instead reacts with HCL (Hydrochloric acid) to form H20 & NaCl.
It would be wonderful if we teach them right things right & help humanity learn faster!!” (retrieved Aug 12, 2019, from https://www.linkedin.com/posts/ajjames_augmentedreality-ar-innovation-activity-6562906886130241536-wNCY/)

A., I.
“I would like to note that electrons are not volumetric particles (spheres) that orbit the atom nucleus, indeed they are present around the nucleus in the form of electron cloud, this is the probability of finding the electron at a certain point with respect to the atom. Additionally, the electron is a volume less particle. I would be amazed if really the correct model is shown and not some old classical physics incorrect info. This old model caused a lot of students to confuse chemistry as they go a little deeper into the subject.” (retrieved Aug 12, 2019, from https://www.linkedin.com/posts/ajjames_augmentedreality-ar-innovation-activity-6562906886130241536-wNCY/)

M., C.
“Interesting idea, but the shape of the water molecule is wrong. There are some cool (free) apps that display correct geometries though :)” (retrieved Aug 12, 2019, from https://www.linkedin.com/posts/ajjames_augmentedreality-ar-innovation-activity-6562906886130241536-wNCY/)

I would say these comments are both correct and incorrect at the same time.  After all, since the demonstration video only shows a few cool looking animations, we don’t know what the educational objective the creator of the cards was trying to achieve.  The video itself would have been much more effective presented as a 1 – 2-minute teaching lesson.  After all, perhaps the creator was trying to help people connect molecular formulas to materials H2O (water) NaCl (table salt).  In that case, the cards are not that bad.

If they are trying to teach chemical reactions, then the cards have several problems.  However, even if they are trying to explain chemical reactions should the electrons be displayed as clouds or discrete bodies.  Anyone that has a chemistry degree knows that electron clouds are the correct representation.  However, to understand electron clouds, you need to get into quantum mechanics. Leaving aside the question of whether the students have the math skills to truly delve into quantum mechanics are they ready to learn quantum mechanics.

Anyone that teaches knows we can’t learn everything all at once.  Also, successful education requires a framework to build on.  Students incorporate new information into existing knowledge.  That information needs a starting point.  One of the problems with chemistry is that we can’t directly observe a lot of the things we teach.  In cases like this, models and cartoons are a good starting point. 

Using representations, we can start building up knowledge.  The dotes make it easier for students to understand that covalent bonds are a sharing of electrons and that two atoms bound together share electrons.  Does that come across to early student if we use two or three different shaped clouds?  While an understand stoichiometry and what form elements take in the environment, they need to understand chemical bonds and the role electrons play. 

The important thing about teaching tools and models is to use them where they are appropriate. Representations like dot structure are not intended to teach students the physical structure and form of electrons. Educations is not merely the process of moving from simple to complex but also building up a framework and helping student incorporate new and more complex information. The introduction of misconceptions in STEM education is rarely because teachers present the wrong information but because the tools are misused.  

Still I wonder when and how we should start teaching quantum mechanics?

Thanks for Listing to My Musings
The Teaching Cyborg

Your Student Can Find Supernova

“Look up at the stars and not down at your feet. Try to make sense of what you see, and wonder about what makes the universe exist. Be curious.”
Stephen Hawking

Fifty years ago, humans first set foot on the moon.  In recognition of this, I thought I would discuss how astronomy classes can conduct real astronomy research.  As I have said in many of my posts, most current best practices in STEAM education recommend that students perform real science.

One of the arguments I have repeatedly encountered is that real science requires equipment that is too expensive for student labs.  Nothing could be further from the truth.  While scientific equipment on the cutting edge of science can be costly general improvements in technology, mean that students can use hobby grade instruments for scientific observations.

As an example, digital SLR cameras can be used to find supernova.  As a step up a simple telescope and digital camera like many schools already have can also be used.  Having the equipment fixed in a dedicated spot in a shed or dome that opens is helpful but also not necessary.  Students can also set up the equipment each night to make observations.

The basic technique to find supernova is to take lots of pictures of night sky night after night.  Then compare the images and look for a star (you’re looking at galaxies, not individual stars) that gets brighter or appears where there was not a visible star.  The biggest drawback to the discovery of supernova is simply the amount of data that the students will need.  On the website for BOSS Backyard Observatory Supernova Search under the setting up a search page they list supernova discoveries from several individuals

  • Tim Puckett (one of the largest in the world) ~1 SN every 8000 images (300+ SN)
  • Robert Evens ~ 1 SN every 4000 observations (47 SN)
  • Peter Marples ~ 1 SN per 5000 images (8 SN)
  • Me ~ 1 SN every 2800 images (57 SN)

Using these numbers as a baseline, we would find one supernova on average every 4950 images. If we assume a 15-week semester, the class would have to take 330 pictures per week.  Assuming students take one image every minute, 330 images would take 5.5 hours over one night or 2.75 hours over two nights.   With a class of 25 students, each student would need to examine 198 images or 13-14 images per week.  A better approach would be to have two students review 396 images so that two students separately review each 198-image set. All these numbers seem reasonable for a semester-long class.

Once students capture the images, students analyze the images in one of three methods.  In all methods, you compare the new images you take with a set of reference images.  You can either make your reference images.  Or download reference images from the Digitized Sky Survey (DSS). You then compare your new images to the reference images and look for differences.  The first way to do this is to compare the two images side by side and look for differences.  The second method is to blink the images. The new image is aligned and laid on top of the reference image, and the computer rapidly clicks between them. A free tool to do this is Starblinker.  The third method is automated software, but that can be expensive and is only suitable for projects that collect 1000s or more images a night (there are problems and drawbacks to automated software I will not get into). 

When your students discover a new Supernova (we will assume that if you review enough images, you will be successful.), the students can learn about submitting their discovery to Central Bureau for Astronomical Telegrams. A new supernova report will require the students to take additional images and measurements.

Any scientific research can be used to teach students the basics of research and observation.  The search for and discovery of supernova can be included in everything from a class for nonmajors to a dedicated research seminar.  Additionally, the students that conduct this type of research can be in almost any age group.  When we teach scientific research, it is essential to remember that science is a process and method of looking at the world, not the equipment we use.  So, get out there and find some stars that blew up.

Thanks for Listing to My Musings
The Teaching Cyborg

But I Can’t Use Images in PowerPoint!

“If you can’t write your message in a sentence, you can’t say it in an hour.”
Dianna Booher

A few weeks ago I wrote about PowerPoint (Blame the Tools, It’s Easier).  In addition to the idea that PowerPoint “forces” the use of bulleted lists the most common complaint I hear is about images.  The use of images in PowerPoint is such a common problem that I have hosted and given workshops on the topic.

When it comes to the use of images in PowerPoint, the critical thing to remember is to maximize the use of space. Unfortunately, this is not always as easy as it might seem.  If we assume you are making slides for a presentation, then the available space is determined by the projector, not your computer.  Two factors determine the available space of your projector the resolution and aspect ratio.

Resolution is the number of pixels on the screen, while the aspect ratio is the shape of the screen.  Fortunately, if your computer has enough processing power to handle your slides (most modern computers do) you only really need to worry about aspect ratio. Your computer will still run your presentation even if your image is too big.  If you use the zoom function, magnifying glass on the presenter’s screen or the plus and minus keys, there is even an advantage to using oversize pictures.

With regards to the aspect ratio, most projectors and computer screens have a 16:9 aspect ratio.  The 4:3 aspect ratio went out of production for computers sometime around 2012.  However, you still might encounter some 4:3 projectors. As a reference today (2019) most Windows-based laptops use the 16:9 aspect ratio while MacBook’s use 16:10.

The first thing to do when designing a presentation is to find out the aspect ratio of the projector you will be using.  When researching projectors, you will most likely find the resolution/aspect ratio listed like VGA, XGA, and Full HD. These letters are the abbreviation of a monitor standard.  Each standard represents a resolution and aspect ratio.  VGA stands for Video Graphics Array and has a resolution of 640 x 480 pixels and an aspect ratio of 4:3. Some common monitor standards you could encounter are

  • XGA        1024 x 768          4:3
  • 720p      1280 x 720          16:9
  • WXGA    1280 x 720          16:9
  • WXGA    1280 x 800          16:10
  • 1080p    1920 x 1080        16:9

If you encounter other resolution, you can look them up on Wikipedia’s Display resolution page. Alternatively, if all you have is the resolution say 1600 x 1200, you can use an online aspect ratio calculator, 1600 x 1200 (UXGA) has a 4:3 aspect ratio.  When you know the aspect ratio of the projector, you can design the slides to fill the screen.  Below are four images that show a 16:9 slide on a 4:3 screen and a 4:3 slide on a 4:3 screen than a 4:3 slide on a 16:9 screen and 16:9 slide on a 16:9 screen.

4 slides that show 4:3 content on 4:3 and 16:9 slides and 16:9 content on 4:3 and 16:9 slides
4 slides that show 4:3 content on 4:3 and 16:9 slides and 16:9 content on 4:3 and 16:9 slides

The first thing is to create a presentation that matches your projector.  The current default aspect ratio for a PowerPoint presentation is 16:9. PowerPoint users can change the ratio to 4:3; click on Design in the top menu then on the right side of the design bar click slide size and choose 4:3.  If you happen to have the 16:10 resolution you will need to click Custom instead of 4:3 then from the Slide Sized dropdown menu choose On Screen Show (16:10).  Now that we have our slides setup, we can add images.  Under the new slides button, there are six options, several of them will accept images. However, as I said when I talked about the font, making a good presentation is all about defeating the presets and built-in options.

Below are Six options (A-F) that PowerPoint “suggested.”  Unless you are teaching a class on design, I am going to assume that the critical content is the image.  In this case, the best “default” option is F However; the title box covers up a portion of the image, our primary content.

a slide showing 6 default option for image layout in PowerPoint. On Slide F the image completely fills the screen and a white text box displays the title at the bottom.
a slide showing 6 default option for image layout in PowerPoint. On Slide F the image completely fills the screen and a white text box displays the title at the bottom.

Instead of a default option, I start with a blank slide and insert an image.  If you select the image and then click and hold shift + ctrl (shift + ⌘ mac) and the image will resize from the center evenly along all edges.  That will give you the slide below a single picture filling the slide.

A slide filed with an image of the Carlsbad Cavern Big room and no text.
A slide filed with an image of the Carlsbad Cavern Big room and no text.

Now we need to add a title the option that leaves the image completely clear is to have the title on the previous slide like the following images.

A title slide saying Carlsbad Cavers The Big Room.
A title slide saying Carlsbad Cavers The Big Room.
A slide filed with an image of the Carlsbad Cavern Big room and no text.
A slide filed with an image of the Carlsbad Cavern Big room and no text.

If you need the title on the image, there are two ways to do it.  The first is to insert a text box and find a color that the audience can read on top of the image.  Finding a readable text color can be difficult if the image has a lot of different colors and a broad contrast range.  When you have found a color that works enter your title. The following image uses white text. 

A slide filed with an image of the Carlsbad Cavern Big room and white title text.
A slide filed with an image of the Carlsbad Cavern Big room and white title text.

The second and my preferred method of adding text to an image is to insert a text box fill it with a 60 -70% transparent white and then use black text.  An example of the translucent text box with black text is below.

A slide filed with an image of the Carlsbad Cavern Big room. With a text box filled with translucent white and black text.
A slide filed with an image of the Carlsbad Cavern Big room. With a text box filled with translucent white and black text.

The reason I prefer the translucent white text box, it always works, and you can still see the picture.  The translucent white generates contrast for the black text on any combination of colors.  Because it always works, I can do it in the same way on every slide.  When designing slides for a teaching presentation, consistency is essential; your audience will note and be distracted by changes.   The only reason you should break consistency is to make a point.  However, remember if you break consistency to make a point only do it once or at most twice if your presentation has discrete sections. 

Again, this post only covers a single piece of one topic.  The selection of color and color palette that works with an image could be another topic all by itself.  The idea of consistency could and probably should be expanded to cover all the slides used in a year-long course, not just one presentation.  Hopefully, this discussion on images in PowerPoints is helpful.  I’m not sure I have gotten PowerPoint out of my system; I may come back to this topic again.

Thanks for Listing to My Musings
The Teaching Cyborg