In this blog, I talk a lot about topics discussed in Intermediate Physics for Medicine and Biology. Almost as interesting is what topics are NOT discussed in IPMB. One example is inductance… Read More

Wednesday was the 100th anniversary of Robert Plonsey’s birth. He is one of the most highly cited authors in Intermediate Physics for Medicine and Biology. Plonsey was born on July 17… Read More

The Taylor series is particularly useful for analyzing how functions behave in limiting cases. This is essential when translating a mathematical expression into physical intuition, and I wou… Read More

In Chapter 14 of Intermediate Physics for Medicine and Biology, Russ Hobbie and I briefly discuss depth of field: the distance between the nearest and the furthest objects that are in focus… Read More

In Chapter 13 of Intermediate Physics for Medicine and Biology, Russ Hobbie and I discuss the attenuation of sound. Water transmits sound better than air, but its attenuation is an even str… Read More

Patrick Blackett.In Chapter 15 of Intermediate Physics for Medicine and Biology, Russ Hobbie and I describe pair production. A photon… can produce a particle-antiparticle pair: a neg… Read More

The Nuclear Energy Option: An Alternative for the 90s.by Bernard Cohen.Today is the one hundredth anniversary of the birth of American nuclear physicist Bernard Cohen. In Intermediate Physic… Read More

I recently published a review in the American Institute of Physics journal Biophysics Reviews about the magnetocardiogram (Volume 5, Article 021305, 2024). The magnetic field produced by th… Read More

Yesterday’s attack on Dr. Anthony Fauci during his testimony at the Congressional Select Subcommittee on the Coronavirus Pandemic angers me. I like Dr. Fauci and I like other vaccine s… Read More

“Can the Microwave Auditory Effect be Weaponized?”I was recently reading Ken Foster, David Garrett, and Marvin Ziskin’s paper “Can the Microwave Auditory Effect Be We… Read More

“Magnetoelectrics for Biomedical Applications: 130 Years Later, Bridging Materials, Energy, and Life”I’m always looking for new ways physics can be applied to medicine and… Read More

“FLASH Radiotherapy: Newsflashor Flash in the Pan?” (Med. Phys.46:4287–4290, 2019).I’ve always been a fan of the Point/Counterpoint articles published in the journal… Read More

Homework Problem 7 in Chapter 11 of Intermediate Physics for Medicine and Biology examines fitting data to a straight line. In that problem, the four data points to be fit are (100, 4004), (… Read More

“Prelude No. 1,” from the Well-Tempered Clavichord, by Johann Sebastian Bach. I played it (or tried to play it) back when I was 15 years old.Most of my blog posts are about physi… Read More

Are Electromagnetic FieldsMaking me Ill?by Brad Roth.Recently I stumbled on a YouTube video about critical thinking in education, featuring Melanie Trecek-King (of the website “Thinkin… Read More

In Chapter 10 of Intermediate Physics for Medicine and Biology, Russ Hobbie and I discuss negative feedback loops. Feedback is often used to maintain an important variable nearly constant. T… Read More

Are Electromagnetic Fields Making Me Ill?,by Brad RothEvery year the Kresge Library at Oakland University hosts an event called “Authors at Oakland” where they honor publications… Read More

Recently I was reading an article by Ramsay Lewis and Yuhong Dong in The Epoch Times titled Invisible Electromagnetic Fields: Do They Harm Your Health? My friend and colleague David Garfinkl… Read More

William Catterall, known as “the father of ion channels,” died on February 28 at the age of 77. Russ Hobbie and I cite Catterall’s article on the structure of sodium ion ch… Read More

German biophysicist Erwin Neher turned 80 last week. Neher and Bert Sakmann received the 1991 Nobel Prize in Physiology or Medicine for their development of patch clamping: a method to recor… Read More

Gene Surdotovich and I are hard at work preparing the 6th edition of Intermediate Physics for Medicine and Biology. One change compared to the 5th edition is that we are redrawing most of th… Read More

I've always been fascinated by Stirling’s approximation,ln(n!) = n ln(n) − n,where n! is the factorial. Russ Hobbie and I mention Stirling’s approximation in Appendix… Read More

Intermediate Physics for Medicine and Biology provides, for the first time, a textbook about the role that physics plays in medicine. Well… no. I recently found a textbook that prec… Read More

Allan was born in Johannesburg, the youngest of three children. He spent his teenage years in Cape Town, and was interested in debating, tennis, and acting. He also loved astronomy, which tr… Read More

Numerical Methods That Work,by Forman Acton.The American computer scientist Forman Acton died ten years ago this Sunday. In Intermediate Physics for Medicine and Biology, Russ Hobbie and I c… Read More

Robert Adair.Photo credit: Michael Marsland/Yale University.I try to write obituaries of scientists who appear in Intermediate Physics for Medicine and Biology, but for some reason I didn&rs… Read More

“Havana Syndrome”: A Post Mortem,by Bartholomew and Baloh.Remember the Havana Syndrome? You don’t hear much about it anymore. Recently I read an article titled “&lsqu… Read More

I just learned that my friend Craig Henriquez passed away last summer. Craig earned his PhD at Duke University in their Department of Biomedical Engineering under the guidance of the renowne… Read More

Last week, the plug door panel on an Alaska Airlines Boeing 737 Max airplane detached during flight, leaving a gaping hole in the side of the fuselage. Fortunately, the plane was able to lan… Read More

In Chapter 2 of Intermediate Physics for Medicine and Biology, Russ Hobbie and I discuss log-log plots. Have you ever wondered who made the first log-log plot? The honor goes to French mathe… Read More

Cell Mechanics.In Chapter 1 of Intermediate Physics for Medicine and Biology, Russ Hobbie and I discuss ideal solids and ideal liquids. Ideal solids are covered in Section 1.10, which introd… Read More

Electricity and Magnetism,by Edward Purcell.In Intermediate Physics for Medicine and Biology, Russ Hobbie and I rarely discuss special relativity. We briefly mention that magnetism is a con… Read More

A few weeks ago, I published a blog post about the television show Meeting of Minds. That show from the late 1970s was created and hosted by Steve Allen and featured historical figures as gu… Read More

Thermodynamics is often summarized in three laws. Do Russ Hobbie and I discuss the three laws of thermodynamics in Intermediate Physics for Medicine and Biology? Yes! The First Law We state… Read More

One Hot Summer,by Rosemary Ashton.I recently finished Rosemary Ashton’s book One Hot Summer: Dickens, Darwin, Disraeli, and the Great Stink of 1858. Her prologue begins What was it lik… Read More

Louis Pasteur (1822–1895)One recurring theme in this blog is how scientists make the transition from working in the physical sciences to studying the biological sciences. Indeed, this… Read More

The Deadly Rise of Anti-Science,by Peter Hotez.This week I read The Deadly Rise of Anti-Science: A Scientist’s Warning, by Peter Hotez. Every American should read this book. In his int… Read More

An antiscatter grid.Episcophagus, CC BY-SA 4.0, via Wikimedia Commons.In Chapter 16 of Intermediate Physics for Medicine and Biology, Russ Hobbie and I discuss the antiscatter grid used in r… Read More

When my wife and I were in Paris several years ago we visited the Musée de l’Orangerie, where Claude Monet’s beautiful water lily murals are displayed. Monet (1840–1… Read More

Last week I introduced the Helmholtz coil and the Maxwell coil. The Maxwell coil is useful for creating the magnetic field gradient needed for magnetic resonance imaging. At the end of the p… Read More

To do magnetic resonance imaging, you need a static magnetic field that is uniform and a switchable magnetic field that has a uniform gradient. How do you produce such fields? In this post… Read More

A teacher affects eternity; he can never tell where his influence stops. Henry Adams Stephen Clough, from the 1975Homestead Jr.-Sr. High School Yearbook.How does someone end up being… Read More

J. Robert Oppenheimer.Did you watch Oppenheimer in the theater this summer? I did. The movie told how J. Robert Oppenheimer led the Manhattan Project that built the first atomic bomb during… Read More

In Chapter 14 of Intermediate Physics for Medicine and Biology, Russ Hobbie and I discuss the risk of DNA damage—and therefore cancer—caused by ultraviolet light from the sun. Fi… Read More

In Chapter 2 of Intermediate Physics for Medicine and Biology, Russ Hobbie and I discuss the problem of decay plus input at a constant rate. Suppose that in addition to the removal of y fro… Read More

In Chapter 2 of Intermediate Physics for Medicine and Biology, Russ Hobbie and I discuss semilog plots, where the vertical axis is marked using a logarithmic scale. In this case, a constant… Read More

An episode of Meeting of Minds, with (l-r) Atilla the Hun, Emily Dickinson, host Steve Allen, Charles Darwin, and Galileo Galilei. When I was a teenager, one of my favorite shows was Me… Read More

Ten years ago yesterday, on September 7, 2013, Physicist Albert Bartlett died at the age of 90. Russ Hobbie and I mentioned Bartlett in Chapter 2 of Intermediate Physics for Medicine and Bio… Read More

When listening to NBC Nightly News on August 24, I heard Lester Holt discuss Japan’s plan to release into the Pacific Ocean treated wastewater from the Fukushima nuclear power plant, t… Read More

In Intermediate Physics for Medicine and Biology, Russ Hobbie and I don’t talk about homeopathy (thank goodness!). A homeopathic medicine is one that has been diluted with water multip… Read More

Paul Maccabee (1944–2023).Photo used with permission from theDownstate Health Sciences University website.My friend and collaborator Paul Maccabee died on April 24. Paul was a pioneer… Read More

Congress is currently considering the “Connect Our Parks Act.” It is a bill to require the Secretary of the Interior to conduct an assessment to identify locations in National Pa… Read More

This Sunday is the 120th anniversary of the birth of American physicist Philip Morse (1903–1985). Russ Hobbie and I mention Morse in Chapter 13 of our book Intermediate Physics for Med… Read More

John Moulder, from Khurana et al. (2008) Med. Phys., 35:5203, with permission from Wiley.John Moulder, a leading expert in radiation biology, died about a year ago (on July 17, 2022; I wasn… Read More

Today I want to talk to high school students who, when they attend college, might be majoring in biological physics. What does a biological physics major look like? Below I present my vision… Read More

Want a short course in vector calculus? You can find one in Intermediate Physics for Medicine and Biology. Divergence The divergence is defined in Section 4.1 in IPMB, when discussing the… Read More

Have you ever been reading a book, making good progress with everything making sense, and then you suddenly stop at say “wait… what?”. That happened to me recently as I wa… Read More

The Age of Napoleon, by Will and Ariel Durant,Volume 11 of The Story of Civilization.Regular readers of this blog may recall that over the last few years I’ve been reading Will and Ari… Read More

Any good undergrad statistical mechanics class analyzes the partition function. However, Russ Hobbie and I don’t introduce the partition function in Intermediate Physics for Medicine a… Read More

Gene Surdutovich and I are hard at work on the 6th edition of Intermediate Physics for Medicine and Biology. So far, the main thrust of our work involves LaTeX and Mathematica.Russ Hobbie an… Read More

Hanson, L., “Is Quantum Mechanics Necessary for Understanding Magnetic Resonance?”Concepts Magn.Reson., 32:329–340, 2008In Chapter 18 of Intermediate Physics for Medicine a… Read More

Intermediate Physics for Medicine and Biology assumes the reader knows calculus. Most medical doctors and biologists have studied some calculus, but I’m not sure they remember much of… Read More

A Paramecium aurelia seen through an optical microscope. Source: Wikipedia (http://en.wikipedia.org/wiki/Image:Paramecium.jpg)Homework Problem 28 at the end of Chapter 2 in Intermediate Phys… Read More

Breathless, by David Quammen.Whenever David Quammen has a new book, I put it on my “to read” list. Recently I finished his latest: Breathless: The Scientific Race to Defeat a Dea… Read More

King Charles III of England was crowned this week. What’s that got to do with Intermediate Physics for Medicine and Biology? Well, the king is a big supporter of alternative medicine… Read More

Thank you for your interest in the 5th edition of Intermediate Physics for Medicine and Biology. We’re considering a 6th edition and we would like to get your opinions and input. Some… Read More

Roth, B. J., 2023, Biomagnetism: The first sixty years. Sensors, 23:4218. The last two blog posts have dealt with biomagnetism: the magnetic fields produced by our bodies. Some of you might… Read More

When I was on the faculty at Vanderbilt University, my student Marcella Woods and I examined the magnetic field produced by electrical activity in a sheet of cardiac muscle. I really like th… Read More

One of the key limitations of the magnetoencephalogram (MEG) is that it’s not sensitive to a radial dipole. What does this mean? The MEG is the magnetic field outside the head produced… Read More

For three years I’ve dodged the bullet, but no more; I have covid. I’m doing fine, thank you. For me the symptoms were similar to a moderate cold. My doctor put me on a five-day… Read More

Exclamation points are rare in scientific writing, but I like them. Occasionally Russ Hobbie and I use them in Intermediate Physics for Medicine and Biology. They’re fine as long as yo… Read More

Over the last couple years, I’ve been writing lots of review articles. In the last few weeks three have been published. All of them are open access, so you can read them without a subs… Read More

Why Should We Abolish Daylight Saving Time?  J. Biol. Rhythms, 34:227–230, 2019. Last Sunday, we all switched from standard time to daylight saving time, losing an hour of sl… Read More

I’m a fan of Dianna Cowern, better known as Physics Girl, who makes Youtube videos about physics that would be helpful for readers of Intermediate Physics for Medicine and Biology. Thr… Read More

Cobalt Blues,by Peter Almond.I recently read Cobalt Blues: The Story of Leonard Grimmett, the Man Behind the First Cobalt-60 Unit in the United States (Springer, 2013), written by Peter Almo… Read More

To understand biological physics, you must know the properties of water. In Intermediate Physics for Medicine and Biology, Russ Hobbie and I discuss water’s density, compressibility, v… Read More

In Problem 14 of Chapter 7 in Intermediate Physics for Medicine and Biology, Russ Hobbie and I chose a strange-looking function to represent the intracellular potential along a nerve axon, v… Read More

Abe Liboff, in hisoffice at Oakland UniversityOakland University physicist Abe Liboff died recently. A notice from President Ora Hirsch Pescovitz, published on the OU website, stated: It is… Read More

Fifty Outstanding Medical Physicists. In 2014, to mark its 50th anniversary, the International Organization for Medical Physics published a list of 50 medical physicists who have made an out… Read More

Bust of Félix Savartin the Institut de France.From Wikipedia.  I’m fascinated by scientists who make the transition from medicine to physics, which is the opposite of… Read More

Alexander PopeI mentioned before in this blog that I’m reading Will and Ariel Durant’s eleven-volume masterpiece The Story of Civilization. Recently, in Volume Nine about The Age… Read More

The Invisible Rainbow,by Arthur Firstenberg.Over Christmas break, I read The Invisible Rainbow: A History of Electricity and Life, by Arthur Firstenberg. What can I say about such a book? Fi… Read More

Physics,by Halliday and Resnick.Robert Resnick, physics textbook author extraordinaire, was born 100 years ago last Wednesday (January 11, 1923). A Rensselaer Polytechnic Institute website s… Read More

Edith Anne StoneyToday is Edith Anne Stoney’s birthday; she was born on January 6, 1869. In an article that appeared in the December, 2013 issue of Scope (the quarterly magazine of the… Read More

When I worked at the National Institutes of Health, I studied transcranial magnetic stimulation. In Chapter 8 of Intermediate Physics for Medicine and Biology, Russ Hobbie and I describe thi… Read More

I encourage students to build their qualitative problem solving skills by recasting equations in dimensionless variables, analyzing the limiting behavior of mathematical expressions, and ske… Read More

Mark HallettLast Monday I attended (over the internet) a Festschrift to honor the retirement of Mark Hallett from the intramural program at the National Institutes of Health. Russ Hobbie and… Read More

Air and Water,by Mark Denny.In Intermediate Physics for Medicine and Biology, Russ Hobbie and I don’t talk much about surface tension. However, in Air and Water, Mark Denny devotes sev… Read More

When discussing the attenuation of sound in Intermediate Physics for Medicine and Biology, Russ Hobbie and I write In acoustics, the attenuation is usually expressed in decibels per meter. A… Read More

In Section 14.4 of Intermediate Physics for Medicine and Biology, Russ Hobbie and I discuss molecular energy levels. In particular, we examine translational, rotational, and vibrational leve… Read More

Forever and Ever, Amen,by Randy Travis.I’m a big fan of country music. After all, I was a graduate student in Music City: Nashville. I used to ride my bike down to 16th Avenue by the o… Read More

The Eighth Day of Creation, by Horace Freeland Judson.In Intermediate Physics for Medicine and Biology, Russ Hobbie and I analyze the role physics plays in the biological sciences. What is t… Read More

The poster for the 2022 International Day of Medical PhysicsMonday, November 7, is the International Day of Medical Physics. The purpose of this annual event, organized by the International… Read More

In Chapter 1 of Intermediate Physics for Medicine and Biology, Russ Hobbie and I introduce a concept from fluid dynamics called the boundary layer. The behavior of a sphere moving through a… Read More

If you shine x-rays through a material and measure the number absorbed by it, you create an x-ray absorption spectrum. The absorption is related to the cross section; the bigger the cross se… Read More

The Art of Electronics,by Horowitz and Hill.Nine years ago I wrote in this blog about the second edition of Horowtiz and Hill’s textbook The Art of Electronics. At the end of that post… Read More

The Last Man Who Knew Everything,by Andrew Robinson.Almost ten years ago in this blog, I speculated about who was the greatest biological physicist of all time, and suggested that it was the… Read More

Grimes DR (2021) Radiofrequency Radiation and Cancer, JAMA Oncology, 8:456–461.In my book Are Electromagnetic Fields Making Me Ill? I discussed the danger of cell phone radiation. Rece… Read More

This week I belatedly learned that Mike Joy died. This was sad news indeed. Joy was a Canadian electrical engineer who measured current density in the body using magnetic resonance imaging… Read More

Drawdown,Edited by Paul Hawken.This blog is about physics applied to medicine and biology, but if we don’t solve the climate crisis there’s no use developing fancier ways to do m… Read More