Diagnostik
7 cards from across every topic, each citing a source. Tap one to open it in the feed.
- How a lab turns a few DNA fragments into billions.
A PCR cycle heats to 94–98 °C to separate the DNA strands, cools to 50–65 °C so short primers can dock, and goes to …
- How an MRI looks inside you without X-rays.
A magnetic field of typically 1.5 or 3 tesla lines up the hydrogen nuclei in your body. Radio pulses tip them over; as …
- How one sound yields two blood pressure numbers.
The cuff squeezes the arm artery shut. As pressure is slowly released, blood spurts through again the moment the …
- How ten electrodes become twelve views of the heart.
A standard ECG sticks ten electrodes on limbs and chest and computes twelve leads from them – twelve viewing angles. …
- How the clip on your finger sees through you.
A pulse oximeter shines red light at 660 nanometres and infrared at 940 nanometres through your finger. Oxygen-rich and …
- How two lines on paper add up to a measurement.
The liquid wicks through a pad and over a conjugate pad holding dried gold particles carrying antibodies, which latch …
- The stethoscope was born of embarrassment and a sheet of paper.
In Paris in 1816, René Laennec was uncomfortable putting his ear directly on a woman's chest. He noticed that a …