Sodium

Most people have heard of sodium, and those who haven’t are generally familiar with its application, although they may not know the vital role it plays.

It is most visible in street lighting. Sodium-vapour lamps are good for night-time illumination because of their high efficiency and because the light they produce penetrates mist and fog particularly well. As the bulb warms up, the sodium vapour becomes excited, emitting a characteristic yellow light of wavelength 589 nm. Today, however, LED street lighting is becoming more popular because of the long lifespans associated with the lamps. It may not be long before the familiar, warm yellow glow of sodium-vapour street lighting becomes a thing of the past.

Despite the bad publicity in recent years (excessive sodium intake increases blood pressure) salt (NaCl) is vital for life. You have around 100 g in your body right now. Around 3 g is lost each day in urine and sweat, which is why it’s a vital part of our diet. In the body, sodium works in conjunction with potassium. As the ions move in and out of nerve axons, they generate waves of electrical pulses that travel through the nervous system.

But there’s much more to sodium than these familiar occurances...