Radiometric Dating: Need to Practice?

Last year, we posted a video explaining how to do three types of radiometric dating problems; we wrote about it in this blog post.

I am pleased to report that the prodigious Matt Taylor has now released an activity with four sample problems that your students can work. The first two problems are pretty typical. In question #1, students are given the half-life and % of the isotope remaining and must figure out the age of the fossil. In question #2, students are given the age and half-life, and they must determine what % of the isotope remains.

The last two questions are different. In #3, students are given the graph of isotope decay and told the half-life of the isotope; they must click on the part of the graph corresponding to a particular time. And in #4, students are given information about the % remaining of three isotopes and must arrange them in order based on their half-lives.

The video is designed to walk students through this content, step by step, and the activity can help students assess their understanding. We encourage you to share both resources with your students — or better yet, go through them together, pay attention when your students struggle, and use your insights to refine your teaching. (Yes, I’m looking right at you, teacher with a growth mindset!)

One Good Clicker Tip

The end of the semester is not a great time to introduce a tip for using clickers; I am sure this post would have been more useful in January! But I can’t control when ideas for blog posts drop into my email, and I received a good one recently.

It’s an article called Clicking Your Way to Flipping Your Class, and it appears in Tomorrow’s Professor—an excellent resource for professors in any discipline. The Tomorrow’s Professor article that recently landed in my inbox is a reprint of an article that originally appeared in the February 2017 issue of the newsletter of the Federation of European Biochemical Societies (http://www.febs.org).

iclicker2, ready for action. (Photo by M. Hoefnagels)

I’m not a big classroom flipper myself, but I am madly in love with clickers. What I like about the “Clicking Your Way…” article is its subject, clicker-based peer instruction. While I don’t follow the author’s methods to the letter, the article reminded me of one of the ways I use clickers in my class. (You can read about another way that I like to use clickers here: “Pointless” clicker questions.)

I use the iClicker2 and enjoy watching the LCD display at my computer as the students’ answers roll in. The display shows how many students have selected each answer choice in real time. If the question is easy or if the students have mastered the material, then I don’t spend a lot of time giving feedback on the question. Here’s an example like that:

What is the charge on an electron? (a) Neutral; (b) Negative; (c) Positive; (d) Depends on the element; (e) Depends on the isotope.

This question comes in the context of a series of questions designed to help students through the difficult concept of polar covalent bonds. Nearly everyone (98%) in my last class got this question right. I could replace it with a more challenging one, or I could keep it in and consider that point to be a cheap-and-easy, morale-boosting reward for participation. So far, I have opted for the latter.

For a more difficult question, the display often reveals that the class is split between two (or rarely, three) choices. Those are my favorite questions because they offer an opportunity for students to learn by teaching each other. Here’s an example of such a question; it requires students to enter a number into their clickers (yet another reason to love iClicker2), but it could easily be converted to a multiple choice question:

How many of the following processes actually exist AND produce two cells that are virtually identical to the original cell?

• Meiosis in bacteria
• Meiosis in animals
• Meiosis in plants
• Mitosis in bacteria
• Mitosis in animals
• Mitosis in plants
• Binary fission in bacteria
• Binary fission in animals
• Binary fission in plants

The most popular answers are 3, 4, and 6 (the correct answer is 3). As the students enter their answers, I keep an eye on the display. I usually do one of two things if less than ~70% of the students are getting the question right. I may stop the polling (without showing the histogram) and say something like this: “Explain to your neighbor why you selected the answer you did.” After a minute or two of discussion, I poll the same question. Alternatively, I may choose the slightly quicker strategy of keeping the polling going while I tell the students something like “OK, most of you are choosing 3, 4, or 6. One of those is the correct answer. Pick one and explain your choice to your neighbor.” Either way, without any other intervention from me, student performance on the question typically improves.

I am always on the lookout for clicker questions that actually make students think. The blog post I linked in the previous sentence has one example of a good site for clicker resources, and here are some clicker questions from the University of Colorado Science Education Initiative.

Happy clicking!

 

 

 

Cultivating a Growth Mindset in Your Students

This semester, I’ve been reading a lot about teaching with a growth mindset. I wrote about this topic at the end of last semester in a blog post called At the End, I’m Looking to the Start. Since that time, I have been studying Carol Dweck’s Mindset and Saundra Yancy McGuire’s Teach Students How to Learn. Dweck’s book provides a broad overview of the fixed and growth mindsets as they pertain to all aspects of life. Once you are sensitized to the difference, you can start working on making the monologue inside your head less judgmental and more constructive. McGuire’s book focuses on teaching college students, and it is exemplary because of its practical suggestions and positive, success-oriented stance.

Two useful books: (left) Carol S. Dweck’s Mindset and (right) Saundra Yancy McGuire’s Teach Students How to Learn.

This week I presented some of what I’ve learned in an hour-long McGraw-Hill webinar, “I’m Just Not Good at Science”: Cultivating a Growth Mindset in Nonmajors Biology. The webinar was about recognizing the fixed vs. growth mindset, not only in what your students say about themselves, but also in what you say about your students. I also shared many suggestions from McGuire’s book, notably about how to help students recognize problems in their own studying and how to help them develop more effective behaviors. In the last part of the webinar, I showed some of what I do in my own class.

The clip below is a 6.5-minute excerpt from the second part of the webinar. It’s about what you can do after you return an exam, when many of your students first become painfully aware that something is wrong. You’ll notice references to the chat window, which you unfortunately cannot see in the video clip. The end of the clip references the “study cycle,” something you can learn a lot more about in McGuire’s book; you may also be interested in this excellent short video introduction from Louisiana State University.

Incidentally, if you’ve read McGuire’s book you already know that she does not care for the phrase “study skills.” She prefers “metacognitive learning strategies,” which McGuire finds grabs student interest. I am not sure I agree, so I’ve gone with the simpler phrase.

If you’d like a link to the full webinar, please add a comment below and I will arrange to have it sent to you.

 

 

 

 

Reblogging: GMOs vs. Artificial Selection

The Ricochet Science blog post below—written by a talented college senior—is an interesting introduction to the difference between GMOs and organisms that are the products of artificial selection. I want to share it with you because it’s informative and entertaining, but first I’ll clarify one point that isn’t completely clear from the original.

In genetic engineering, scientists use DNA technology to directly manipulate a genome. Genetic engineering produces genetically modified organisms (GMOs). A GMO may be a transgenic organism—one that has received DNA from another species—or may have had its own genes activated or deactivated to produce new phenotypes. For example, some cotton plants are GMOs that are transgenic because they have a gene encoding a bacterial toxin in their genome. The transgenic cotton plant is toxic to pests like moth caterpillars. If, instead, the cotton plant’s DNA were modified to boost the expression of an existing gene (perhaps one that promotes large cotton bolls), the cotton would still be a GMO, but it would not be transgenic.

With this clarification in mind, read on and enjoy the original blog post.

[Thank you to Matt Taylor for contributing to this introduction.]

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Picture this, you’re making your lunch for class or work and you decide to pre-slice your apple because it’s easier to eat and heck, why not? Fast forward five hours, you’re already exhausted from the day and all you want to do is eat your apples with some peanut butter, but, SURPRISE! Your apple slices…

via Transgenic or GMO? What is the Difference? — Ricochet Science

TED-Ed video: The Cancer Gene We All Have

My friend and colleague Michael Windelspecht recently produced a useful video about cancer. Complete with compelling animations, narration, and analogies, it’s a great launching point for in-class group work or for a homework assignment. The video’s explanations span from genetics and cell cycle control to cancer’s effects on the organism.

If you watch until the end at the link here (The Cancer Gene We All Have), you’ll see five multiple choice questions and three free-response questions to test your understanding. Below I’ve placed the video if you want to view it on YouTube, but you won’t get the see the assessment questions. Enjoy!

Teaching cell chemistry with Legos

Behold, my trusty bag of Legos … well they’re not actually Legos because I couldn’t find a bag of plain old Legos. All of the Legos nowadays are sold in kits with wheels and roofs and other things I don’t want. So I bought a big bag of plastic bricks that LOOK like Legos. Here they are:

I bought them because my students have such a hard time with the basics of cell chemistry for biology. The main idea I am trying to teach is that food consists of complex organic molecules (proteins, polysaccharides, nucleic acids, and fats) that are broken down into amino acids, monosaccharides, nucleotides, glycerol, and fatty acids via hydrolysis reactions in digestion. These small molecules enter the bloodstream and are distributed to cells, which use them to build their own large molecules or use them in respiration. It’s easy once you know how it works, but it’s pretty hard to learn it for the first time.

So I started using my Legos … err, plastic bricks … in Action Center, to help students use their hands to work with the ideas. Here is my strategy, in pictures.

1 — Food represents a mixture of organic molecules. Imagine that the assembly of blocks pictured below is a bite of a bacon, lettuce, and tomato sandwich. It contains proteins, polysaccharides, nucleic acids, and fats — the different shapes and colors of the bricks represent these different molecules.

2 — In the intestines, digestion (hydrolysis) breaks the food into smaller molecules.

3 — These small molecules enter the bloodstream, and cells take them up. Here are a bunch of monosaccharides taken up by a cell.

4 — The cell uses the monosaccharides in respiration (you’d have to smash a brick into bits to illustrate this idea). Or the cell may use them to build polysaccharides, like glycogen, by dehydration synthesis. Below is a “glycogen molecule.”

5 — Cells also absorb amino acids from the bloodstream. Here are a bunch of amino acids taken up by a cell. Notice that the monosaccharides in photo #4 all looked the same, because they were all glucose. The amino acids all look different, thanks to their different R groups.

6 — The cell assembles the amino acids into proteins, again by dehydration synthesis.

7 — Now if another animal eats this organism, what will happen to the proteins, polysaccharides, and other large organic molecule the cell has produced? Why, they’ll be dismantled again, in hydrolysis.

In my experience, building and taking apart these molecules has been really helpful to students in learning the connections between digestion, hydrolysis, dehydration synthesis, and respiration.

Try it yourself! And if you have other ideas for teaching cell chemistry that have worked for you, please share them here.

 

 

At the End, I’m Looking to the Start

I turned in my course grades yesterday and thought I’d spend some time looking back at something that my TAs asked our students in lab to write about during week 1. After the TAs introduced themselves and talked about their portion of the class, we asked the students to combine my own day 1 lecture with the TA presentations to answer this question:

What are some of the obstacles that you feel might keep you from being successful in BIOL 1005?

Motivated students attend a study session outside of class.

Now that the final course grades are in, I thought it might be worth looking back at the answers to see if students correctly anticipated their own obstacles. Some students listed just one; others listed multiple obstacles. I have typed each one below, so some students are represented more than once in each list.

 

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Students who earned an A initially perceived their obstacles as:

• Not being able to comprehend the material because “science is not my strong suit.”
• “I’ve never been good at science.”
• “I do not particularly like science because I do not feel I’m good at it.”
• “I am not the best test-taker even if I study really hard.”
• Not understanding lab materials or information
• Not being able to understand the material
• Having limited time to study (from a first-year student enrolled in 18 hours)
• Having limited background in biology
• Not asking for help when needed
• Course intensity
• Feeling overwhelmed
• Not studying enough
• Finding the class uninteresting and not being motivated to work hard

Students who earned a B initially perceived their obstacles as:

• “I’m not a lover of science.”
• “I’m not a biology or science person.”
• “I really don’t like biology so I can get easily bored.”
• “I am not science brained.”
• “Science has never been my best subject.”
• “I have always struggled with science.”
• “Science was never my best subject in high school. It was hard to stay interested in the material because it seemed pointless and I couldn’t connect it to things in my life at the time.”
• “I’m awful at science. I’ve never been good at it. I’ve always struggled with it.”
• Limited past experience with biology and science
• Past experiences with science classes pose a mental obstacle
• Language (this from an international student with limited English skills)
• Not understanding how to do labs
• Not understanding how the concepts fit together
• Limited math skills
• Not being comfortable with my lab group
• Not having a diligent lab partner
• Adjusting to college life
• Nothing can keep me from being successful if I try as hard as I can
• Not being very outgoing
• Workload
• Workload
• Not being able to keep up with the pace
• Lack of motivation to work on a class in which I am not interested in the topic
• Not putting in the effort needed to succeed
• Forgetting due dates
• Not completing assignments on time
• Remembering to check for course updates every day
• Having commitments that force me to fall behind
• Struggling to stay focused

Students who earned a C initially perceived their obstacles as:

• “Me and biology do not really get along. I don’t get science.”
• “I am not very good at biology.”
• “Science and math skills and biology are not subjects that come easy to me.”
• “I’m not great at science.”
• “I have always had trouble understanding science.”
• “I have never been passionate about biology.”
• “Science is not my favorite subject, and it isn’t a subject I’m naturally good at.”
• “I am not a science oriented person and understanding does not come easily to me.”
• “I’m not very good with sciences.”
• “Any science class is not my easiest course.”
• Limited experience with biology
• Difficulty of biology
• Confusing terminology in biology
• Discouragement and frustration
• Time management
• Keeping priorities straight
• Lack of attendance
• Lack of concentration
• Forgetting to do assignments
• Getting behind on homework
• Keeping up with what is due and when
• Finding the right time and place to study

Students who earned a D, W, or F initially perceived their obstacles as:

• “I have to reread sentences with scientific terms several times before I can understand them.”
• “I am terrible at science and have a hard time learning from a book.”
• “I’ve never been great at math or science.”
• “I have much more of an English/History interest than science and math so understanding certain concepts might be difficult.”
• “I’m not the best science student.”
• Lack of interest in the subject
• I can’t usually connect with microscopic biology
• I have forgotten most of the stuff I have learned about science and biology
• Lack of prior knowledge about science
• Language (from an international student)
• I don’t like just studying definitions; I like hands-on activities
• I may struggle with computational questions
• I don’t have the best study habits
• Keeping up with assignments
• Not having time to complete lab activities
• Study skills
• Time management
• Lack of focus, cellular devices, and difficult lab partners
• Work and class load (this from a student who has two jobs, works 40 hours a week, and enrolled in 23 credit hours)

You may have noticed that I colored some of the statements red. Those all refer to a perceived, inherent inability to understand science. I found it interesting that this mindset accounted for 31% of the statements among students who eventually earned an A, 28% of statements from those who earned a B, 45% from those who earned a C, and 26% from those who earned a D, W, or F. You can probably see whatever message you want in those numbers, but what I choose to see reinforces the idea that success in science has nothing to do with whether a student is “a science person.” Heck, I remember myself asserting (as an undergraduate) that I couldn’t take science classes because “I am not a science person,” but I had never actually tried. Once I took chemistry and earned an A, my mindset about my own abilities flipped 180 degrees.

I have recently been thinking a lot about fixed vs. growth mindset, a concept popularized by psychologist Carol Dweck. If you have a fixed mindset about biology, you believe that you can’t do much to change your limited science talent — it is a “fixed trait.” In other words, if you believe you are simply not a science person, why would you invest your precious time trying to learn about biology? On the other hand, if you have a growth mindset you believe that you can develop your talents with hard work and by learning from your mistakes. On behalf of my own students, I am keen to learn more about how to shift a fixed mindset into a growth mindset.

I also colored a few of the perceived obstacles green; these are not specific to science but rather seem to be rooted in student anxiety about keeping up with a challenging class in general. Finally, blue statements represent students’ self-perceived limitations in study skills or time management.

I found it interesting that students who eventually received an A or a B seemed more likely to express anxiety about how difficult the course would be than those who earned lower grades. Students who ended up with a C or below were honest that a major obstacle could be their general abilities as students. In essence, students who ultimately did better were more likely to blame “a course that’s just too hard” for poor performance, whereas students who ultimately did worse were more likely to blame themselves. That’s the opposite of what I would have expected.

This represents a small snapshot of just one semester, but it may provide a little insight into the student mind. How can we use this information to improve the odds of student success? That’s a good thought question for the upcoming break.

Thank you to Matt Taylor for help with this blog post.

On Obstacles, part 2

My last blog post described three questions we asked students in my nonmajors biology class a few weeks ago. That post described some of the responses to question 1 (“What do you feel is your greatest obstacle in achieving the grade you want in this class?”). Today’s post examines answers to questions 2 and 3. Question 2 was this:

“What is one thing that is being done regularly in lab or lecture that helps you?”

Clicker questions: Two responses tied for the top, with 11 students apiece. One of these responses was “Clicker questions.” It is possible that students perceive clicker questions as a way to pad a sagging grade, but I don’t interpret the response in that way. One reason is that students do not earn “participation points” for clicker questions – they get 1 point for a correct response, and 0 points for an incorrect one. If they miss all three questions one day, they earn 0 points for the day. Although they may discuss the answers with their peers, students are ultimately responsible for paying attention and clicking the right answer. Another reason I think they are not simply “easy points” is that most of the clicker questions require understanding or application; they do not typically reward factual recall.

Students benefit from clicker questions. (Photo by M. Hoefnagels)

Lecture: The other response tied for the top spot had to do with lecture. Eleven students mentioned lecture in general or specific lecture features such as analogies, examples, explanations, or images. In addition, four students mentioned some “non-content” aspects of lecture, like study tips and announcements about upcoming assignments. The mention of study tips in particular surprised me, mostly because students look so utterly disinterested when I present them! I guess my sage advice must be sinking in for a few of the students, so I’ll keep presenting my best ideas for student success.

Hands-on activities: Five students mentioned that they liked it when lab offered hands-on activities that reinforce content from lecture. Another handful mentioned outside help, like Action Center and tutoring with Allyson, our wonderful Peer Learning Assistant for BIOL 1005.

Mariëlle explains a concept during Action Center. (Photo by Mark Walvoord)

 

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While it’s always gratifying to know what’s working, it’s hard to use that information to make improvements. That brings us to question 3:

“Is there something that is not being done that you could see helping you before your next test?”

Review sessions and resources: This question had a clear winner, with 16 students wanting an in-class review session (which was already on the schedule for exam 2). In addition, one student wanted me to tell the class (perhaps unrealistically) “exactly what to know for the test.” Another wanted “a list of possible types of test questions,” and another wanted practice tests. The latter two reflect some ignorance of available resources, because two semesters’ worth of old exams are already posted on my website.

Connecting labs to lectures: Interestingly, nine students mentioned wanting to know more about how labs are connected to the lectures (or simply wanted more help in lab). Last fall, we implemented our semester-long concept mapping project specifically to solve this problem. The basic idea is to build a small concept map near the start of the semester and add to it periodically as new concepts are covered in the class, incorporating terms from both lecture and lab. (You can read about it at the 2016 ABLE conference website; scroll about ¾ of the way down the page to the abstract by Krystal Gayler and Mariëlle Hoefnagels). Perhaps this semester’s TA’s are not emphasizing the purpose of these concept maps like the TA’s did last fall.

Online lecture slides: Incidentally, only one student wanted me to post lecture slides online. As someone who automatically stops paying attention at talks for which I already have the slides, I have resisted this request for the past 19 years. The fact that students are not clamoring for the slides suggests that I am not going too fast in lecture, which is good news for me.

Concept mapping: I want to wrap up this two-post series with a comment from one student, who wrote “Build a concept map WITH us.” In the first post, I ended by speculating on ways to help students build connections. I have so far avoided being too hands-on with concept maps in class, because I want to avoid the implication that the only correct concept map is the one that the instructor builds. I also want students to think for themselves and to perceive that learning is a struggle; I don’t want them to just mimic what I put on the screen. But I wonder if a little coaching would be beneficial. For example, students can come up to the board individually or in pairs to add new terms to the map or to revise existing connections. I can stand to the side, pointing out where language needs to be more specific or where additional connections might work.

A student adds to a concept map. (Photo by M. Hoefnagels)

 

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Conclusions from the survey

Overall, this three-question exercise revealed that some students are afraid of not being able to make the connections they need to be successful, yet they aren’t using the resources that could help. One explanation is that they don’t have time or that they’re lazy. Another is that they don’t feel confident that they know how to use the resources, so using them together in class could make a big difference.

Please share your observations and suggestions by leaving a comment.

On Obstacles, part 1

A couple of weeks ago, I asked my lab TA’s to have our students write their answers to these questions:

What do you feel is your greatest obstacle in achieving the grade you want in this class? What is one thing that is being done regularly in lab or lecture that helps you? Or is there something that is not being done that you could see helping you before your next test?

What hurdles do your students have to clear on their paths to success? Image cred: Wikimedia Commons

We got 60 responses across two sections.

I’d like to share some of their answers with you. The first question, and the subject of today’s post, is “What do you feel is your greatest obstacle in achieving the grade you want in this class?” I’ll tackle the other two questions in a future blog post.

Seventeen students (more than 25% of students who responded) alluded to their difficulty in understanding how the material fits together. In a way, I am not surprised that this response led the pack, because I frequently emphasize to my students that memorizing vocabulary words will not be enough to do well in the course. On the other hand, it is puzzling because I provide so many resources that should help students focus on connections. Or at least I think I do … hmm. I will return to this point at the end of this post.

About 10 students alluded to time in some form or another – some have trouble staying on top of all of their classes, some can’t come to office hours or Action Center (supplemental learning session) because of other commitments, some admitted to not devoting enough time to studying, some mentioned “time management” in general, and a couple admitted to procrastinating. Other than reminding students to keep up with the material and not limit their studying to the time immediately preceding an exam, I am not sure what I can do as an instructor to help.

Speaking of time, I won’t waste yours by listing all of the responses that only a handful of students made, but a couple of them are noteworthy. Five students mentioned “information overload.” That one makes a lot of sense to me, partly because this is a 5-hour course and partly because of the two responses I mentioned already. If you have difficulty making connections and don’t study as you go along, I can see how it would be easy to perceive biology as a meaningless series of difficult vocabulary words. If you can instead picture how everything works together, it becomes much easier to incorporate new information without feeling overwhelmed by it all.

Six students mentioned a lack of focus/motivation (this is a nonmajors class, after all). Of these, one wrote, “Biology doesn’t click and it’s not interesting” and another wrote, “I don’t enjoy biology, so it’s not interesting, so it’s hard to learn.” As an instructor who works really hard to help students see why biology is interesting and relevant, these comments are painful to read. If I take the “glass half full” attitude, I could remind myself that only a few students feel that way and that I can’t please everyone. On the “glass half empty” side, I could ask myself what I could do differently to open students’ eyes to biology.

Since students can quickly get bored with subjects they perceive to be incomprehensible, maybe the best thing I can do is to shift my gaze back to the “difficulty in understanding” response that led off this blog post. I already use clicker questions in nearly every class, and the questions focus on understanding (not factual recall). However, perhaps more of them should focus on the big picture instead of on specific processes. We also draw concept maps frequently in Action Center, every few weeks in lab, and occasionally in lecture; perhaps I should work more of them into lecture.

I also provide many resources on my website, but maybe too many students focus on the old exams and not enough of them dig into the Guided Reading Questions. These resources, which you can see on my teaching website, direct students to the most relevant Mastering Concepts, multiple choice, and Write it Out questions from the textbook; I also sprinkle in occasional lists of words they can assemble into concept maps. (Do my “Guided Reading Questions” need a snappier name? Maybe so…I am open to suggestions!) One good way to show them off might be to develop a team exercise, either for class or Action Center, in which each student answers a Guided Reading Question or completes a concept map and then a neighbor “grades” it. That way, they can get practice using an at-home resource and get quick feedback on how they’re doing.

Next time, I’ll share the answers to questions 2 and 3. In the meantime, what are your students’ obstacles, and what are your best ideas for helping students to overcome them?

FOH: Finally, a cure for FMOOWMP

If your students are like mine, no location on campus is scarier than your office. Did you know that their reluctance to come to your office hours actually has a medical cause? I didn’t until I saw this funny new video from Arizona State University, which explains that many students suffer from a disorder called FMOOWMP, or Fear of Meeting One on One With My Professor.

Just like in a commercial for a real pharmaceutical drug, students in the video ask questions, like “Is it dangerous?” and “How did I even get FMOOWMP?” Then, the video proposes a treatment: FOH, or Faculty Office Hours. More questions from students ensue: “Do I need a prescription?” and “Does it hurt?” and “Is it habit-forming?” The commercial ends with testimonials by students who have successfully undergone treatment for FMOOWMP, followed by the obligatory list of side effects (I won’t spoil it for you). The fast-talking disclaimer at the end is worth listening to as well.

I played this video for my class a couple of weeks ago, and I was amazed to see its impact. Suddenly, students started  showing up for my office hours, after weeks of fruitless cajoling on my part. They admitted that the video had played a role in their decision to come in and talk to me. Try it for your own classes — perhaps it will be just what the doctor ordered for you, too.