system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How exactly is a pulse ox able to detect the amount of oxygen in the blood?
gpt
It shines a specific color of light through your finger. That light has it's color changed by the blood in your finger and is then received by a sensor on the other side. The amount and type of change depends on the oxygen content of your blood. (Which is also why veins appear bluer than arteries.) From that it's a simple formula to give an accurate enough measure of blood oxygen.