Why Are Both the State of Matter Plasma and Blood Plasma Called the Same?

The term 'plasma' in physics and biology shares an intriguing commonality that stems from historical and scientific developments. In this article, we will explore the fundamental differences between these two types of plasma and their shared etymological origin.

Plasma in Physics

In the context of matter, plasma is one of the four fundamental states, alongside solid, liquid, and gas. This state is characterized by an ionized gas where a significant number of particles are charged ions and electrons. Plasma occurs under conditions of high temperature or low pressure, allowing it to conduct electricity and respond to magnetic fields.

Examples of plasma include stars (such as the Sun) and neon signs. Plasma is a fascinating state that plays a crucial role in various natural phenomena and technological applications.

Plasma in Biology

In biology, plasma refers to the liquid component of blood that suspends cells such as red blood cells, white blood cells, and platelets. This clear liquid is primarily composed of water, electrolytes, proteins, nutrients, hormones, and waste products. Blood plasma's primary function is to transport nutrients, hormones, and proteins throughout the body.

Etymology and Commonality

The term 'plasma' in both contexts shares a linguistic root that conveys the idea of a formative substance. This commonality is particularly interesting as it highlights the evolution of scientific terminology.

The word 'plasma' in the context of blood was first coined by Czech anatomist and physiologist Johannes Purkinje. In the early 19th century, Purkinje noted that blood consisted of two components: bodies (corpuscles) including red and white blood cells, and a remaining clear watery liquid. This discovery came at a time when strong advances in chemistry and physics were making significant strides.

As medicine began to adopt the methodologies of the hard sciences, the concept of plasma gained prominence. Purkinje named the watery liquid 'plasma' due to its similarity to the state of matter discovered in superheated gases. Irving Langmuir, a pioneering scientist in the field of plasma physics, further formalized the term in his groundbreaking research. He named the collection of ions and electrons in a highly ionized gas 'plasma,' likely because the ionized gas reminded him of the clear liquid that Purkinje had described.

A Historical Perspective

The naming of plasma states is a fascinating tale that intertwines scientific discovery, etymology, and the evolution of scientific language. Langmuir explained this in his seminal paper 'Oscillations in Ionized Gases' in Proc. Nat. Acad. Sci. U.S. vol. 14, p. 628 (1928), noting that the term plasma was a perfect descriptor for both concepts, reflecting their shared nature as formative substances.

While the two types of plasma are fundamentally different in nature and context, the shared term highlights the interconnectedness of scientific knowledge and the importance of historical context in the development of scientific terminology. Understanding this shared origin can provide valuable insights into the evolution of scientific fields and the language we use to describe them.