In a charming letter published in 1774, Benjamin Franklin described an experiment in which he had poured “not more than a teaspoonful” of oil onto a pond, which he found sufficient to calm the water despite a choppy wind. What, you may be wondering, connects Franklin, ponds, tears, and salad dressing? In the last “What … Continue reading How are tears like salad dressing? — What is biophysics? #9
You’re full of amazing liquids. How can a liquid be amazing? One way is to have properties that change depending on how strongly the liquid is pushed. The speed at which a fluid flows depends on the force that’s driving it, and the proportionality between force and flow is known as the viscosity of the … Continue reading How are tears like ketchup? — What is biophysics? #8
No. Nor are atoms, viruses, or grains of sand. It is a fundamental truth that everything is in motion, shaking, twisting, and turning at random with an intensity that depends on temperature, motionless only at the unattainable limit of absolute zero. Though this is a manifestation of physics, its consequences for biology are profound and … Continue reading Are molecules ever still? — What is biophysics? #7
I regularly teach classes on energy, environment, climate, etc., for non-science major undergraduates at the University of Oregon. Inspired by some blog comments elsewhere, I thought I’d list list some books on this subject that I like. It’s especially worth noting books aimed at the general, non-specialist reader that are nonetheless quantitative. I firmly believe … Continue reading Books I Like about Energy, Climate, and Civilization
The realization that electromagnetic waves are quantized — that light interacts in discrete packets — marked the beginning of quantum mechanics. Whether this fundamental attribute of the physical world sets the performance limits of human vision is a fascinating biophysical question. It’s so fascinating that Bill Bialek’s excellent graduate-level biophysics textbook begins with it, and … Continue reading Can you see single photons? — What is biophysics? #6
A more technical post than most. If the symbol and the equation look familiar to you, you’ll be fine. If not, you may still like the post, but in case you’re about to depart I’ll put my customary link to my pop-science biophysics book’s description here, and also share this week’s news that it will … Continue reading What does the Heisenberg Uncertainty Principle have to do with microscopy?
I’ll touch on the important question of how students learn from in-person vs. remote courses by showing just one graph based on the class I taught last term. Adding a bit of commentary, I note a conundrum that I think universities have avoided addressing.. Plotted below are the mean and standard deviations of the overall … Continue reading The perils of online learning, in one graph
We’ve all seen ants carrying seeds, crumbs, other insects — things whose mass is a good fraction of their own. Most of us couldn’t lift things that are so heavy relative to ourselves, and so ants and many other tiny creatures have reputations for being strong. Is this justified? Answering this question brings up the … Continue reading Are Ants Really So Strong? — What is biophysics? #5
I wrote this essay for the Princeton University Press “Ideas” site as a stand-alone piece connected to my new pop-science biophysics book. It appeared yesterday, and I’m posting it here as well (with permission). DNA is stuff: physical, tangible, material. We all know this; we can even picture in our minds its famous double helical … Continue reading The Physicality of Life
The fourth in a series of biophysical questions (one, two, three). If you put your hand on your chest you’ll probably realize that your heart is a bit left-of-center. Or perhaps not: about one in 10,000 people have their heart on the right. No one’s heart lies exactly on the body’s midline, nor does anyone’s … Continue reading Why is your heart on your left side? (Or is it?) — What is biophysics? #4
The Eighteenth Elephant 