Helium

Definition

Helium is a colorless, odorless, and inert gas that is the second lightest element in the periodic table. It is widely used in various applications, including cryogenics, balloons, and as a component in Archimedes' Principle.

5 Must Know Facts For Your Next Test

1. Helium has a very low density, making it much lighter than air, which allows it to be used in balloons and airships.
2. Helium is an inert gas, meaning it does not react with other elements, making it useful in various applications where chemical reactivity is undesirable.
3. Helium is commonly used in cryogenic applications, such as cooling superconducting magnets, due to its low boiling point of -268.9°C (-452°F).
4. Helium is often used in diving applications, as it can be mixed with oxygen to create a breathing gas that reduces the risk of nitrogen narcosis at depth.
5. The low density of helium plays a crucial role in Archimedes' Principle, as it affects the buoyant force exerted on objects immersed in the gas.

Review Questions

• Explain how the low density of helium contributes to its use in balloons and airships.
  • The low density of helium, which is much lighter than air, allows it to provide a significant buoyant force when contained within a balloon or airship. This buoyant force can lift the weight of the balloon or airship, as well as any additional cargo or passengers, enabling them to float and fly through the air. The low density of helium is a key factor in making these types of lighter-than-air vehicles possible, as the buoyant force generated by the helium overcomes the downward force of gravity acting on the entire system.
• Describe the role of helium in Archimedes' Principle and how it affects the buoyant force on objects immersed in the gas.
  • Archimedes' Principle states that the buoyant force on an object immersed in a fluid is equal to the weight of the fluid displaced by the object. In the case of helium, its low density compared to air means that the weight of the displaced helium is less than the weight of an equal volume of air. This reduced buoyant force exerted by the helium on an object immersed in it, compared to an object immersed in air, can be used to determine the object's density and whether it will sink or float in the helium environment.
• Analyze the use of helium in cryogenic applications and explain how its low boiling point contributes to its effectiveness in these applications.
  • Helium's extremely low boiling point of -268.9°C (-452°F) makes it an ideal cryogenic fluid for cooling applications, such as in the operation of superconducting magnets. The low boiling point allows helium to maintain a very low temperature, which is necessary for the proper functioning of superconducting materials. This cryogenic property of helium is crucial in various scientific and technological applications, where maintaining extremely low temperatures is essential for achieving desired performance and efficiency. The ability of helium to remain in a liquid state at such low temperatures, without the need for high-pressure containment, further enhances its suitability for cryogenic applications.

Related terms

Buoyancy: The upward force exerted by a fluid on an object immersed in it, which is equal to the weight of the fluid displaced by the object.

Density: The mass per unit volume of a substance or object, which determines its relative heaviness or lightness.

Archimedes' Principle: The principle that states that the buoyant force on an object immersed in a fluid is equal to the weight of the fluid displaced by the object.