Room temperatureColloquially, room temperature is a range of air temperatures that most people prefer for indoor settings. These temperatures feel comfortable to people wearing typical indoor clothing. Human comfort can extend beyond this range depending on humidity, air circulation and other factors. In certain fields, like science and engineering, and within a particular context, room temperature can mean different agreed-upon ranges. In contrast, ambient temperature is the actual temperature, as measured by a thermometer, of the air (or other medium and surroundings) in any particular place.
IsotopeIsotopes are distinct nuclear species (or nuclides, as technical term) of the same element. They have the same atomic number (number of protons in their nuclei) and position in the periodic table (and hence belong to the same chemical element), but differ in nucleon numbers (mass numbers) due to different numbers of neutrons in their nuclei. While all isotopes of a given element have almost the same chemical properties, they have different atomic masses and physical properties.
Degrees of freedom (physics and chemistry)In physics and chemistry, a degree of freedom is an independent physical parameter in the formal description of the state of a physical system. The set of all states of a system is known as the system's phase space, and the degrees of freedom of the system are the dimensions of the phase space. The location of a particle in three-dimensional space requires three position coordinates. Similarly, the direction and speed at which a particle moves can be described in terms of three velocity components, each in reference to the three dimensions of space.