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Hot Air Balloon JavaScript Simulation Applet HTML5

 

 

 

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Description This virtual lab shows how an aerostatic balloon works. It is a nice example of application of the Archimedes' principle
The buoyant force (Fl) of the aerostatic baloon is obtained by heating air inside its cavity. The buotant force is due to the difference of density between the hot air inside and the cold air outside the balloon cavity. The buoyant force compensate the balloon weigth (w) (having into account the ballast (wl ) and people weight).
The following assumptions have been made in the model:

  • The air is a perfect gas. Therefore air density can be computed with the following equation : density=P/R*M /T. Where R is the constant of ideal gases, M is the molecular weigth of the air, P is the air pressure and T the air temperature.
  • The standard atmosphere model from the surface to 11 km altitude is used to describe the variations of the temperature and pressure with altitude. This model states that the temperature decreases 6.5 K per Km (T=T0-6.5K/Km*h(km)) and the pressure follows the following equation: P=P0*(T0/T(h))^-5.256. Where T0 and P0 are the temperature and pressure at sea level.
Authors Carla Martín
Dpto. de Informática y Automática
E.T.S. de Ingeniería Informática, UNED
Juan del Rosal 16, 28040 Madrid, Spain  

Translations

Code Language Translator Run

Credits

Carla Martn; Tan Wei Chiong; Loo Kang Wee

Executive Summary:

This document provides a briefing on the "Hot Air Balloon JavaScript Simulation Applet HTML5" resource available on the Open Educational Resources / Open Source Physics @ Singapore website. The applet is a virtual lab designed to demonstrate the principles behind how an aerostatic balloon works, specifically focusing on Archimedes' Principle. It utilizes a JavaScript simulation embedded in an HTML5 webpage. The description highlights the key physics concepts involved, the underlying assumptions of the model, its features for teachers, and provides links to different versions. The resource is part of a larger collection of interactive physics and mathematics simulations.

Key Themes and Important Ideas/Facts:

  1. Demonstration of Archimedes' Principle: The core function of the simulation is to illustrate how a hot air balloon operates based on Archimedes' Principle. The description explicitly states: "This virtual lab shows how an aerostatic balloon works. It is a nice example of application of the Archimedes' principle."
  2. Buoyant Force and Density Difference: The lifting force of the balloon is explained through the concept of buoyant force, which arises from the density difference between the hot air inside the balloon and the colder air outside. "The buoyant force (Fl) of the aerostatic baloon is obtained by heating air inside its cavity. The buotant force is due to the difference of density between the hot air inside and the cold air outside the balloon cavity." This buoyant force counteracts the balloon's weight, including the weight of the ballast and any occupants. "The buoyant force compensate the balloon weigth (w) (having into account the ballast (wl ) and people weight)."
  3. Underlying Physics Model: The simulation is based on specific assumptions about the behavior of air:
  • Perfect Gas Law: The air is treated as a perfect gas, and its density is calculated using the equation: "density=P/R*M /T. Where R is the constant of ideal gases, M is the molecular weigth of the air, P is the air pressure and T the air temperature." This allows the simulation to model the change in air density with temperature and pressure.
  • Standard Atmosphere Model: The simulation incorporates a standard atmospheric model (up to 11 km altitude) to account for the variation of temperature and pressure with altitude. The description provides the formulas used: "This model states that the temperature decreases 6.5 K per Km (T=T0-6.5K/Kmh(km)) and the pressure follows the following equation: P=P0(T0/T(h))^-5.256. Where T0 and P0 are the temperature and pressure at sea level."
  1. Interactive Features for Learning: The simulation is designed to be interactive, allowing users to observe the effect of different parameters on the balloon's behavior. The "For Teachers" section highlights that the rising and falling of the balloon is influenced by:
  • Ambient temperature (T0)
  • Initial air pressure (P0)
  • Mass of the hot air balloon (m) The simulation also includes graphical representations: "The left graph of the simulation shows the actual hot air balloon. The right graph plots the graph of pressure (blue) and height (green) against time." Users can control the burner ("Turning on the burner causes the hot air balloon to rise, turning the burner off causes it to descend") to observe the resulting changes.
  1. Authorship and Credits: The simulation was authored by Carla Martín from UNED (Spain), with contributions from Tan Wei Chiong and Loo Kang Wee. This provides context and attribution for the resource.
  2. Availability and Embedding: The simulation can be embedded into other webpages using an iframe code provided: <iframe width="100%" height="100%" src="https://iwant2study.org/lookangejss/02_newtonianmechanics_6pressure/ejss_model_Aerostatic_Balloon/Aerostatic_Balloon_Simulation.xhtml " frameborder="0"></iframe>. Links to different versions of the simulation are also provided, suggesting potential variations or updates.
  3. Context within a Larger Resource: The simulation is part of a broader collection of "Interactive Resources" under the "Physics" and "Thermal Physics" sections of the Open Educational Resources / Open Source Physics @ Singapore website. The extensive list of other applets on the page indicates a rich repository of interactive learning tools covering various physics and mathematics topics. The "Popular Tags" section reveals common themes within the collection, such as "Newtonian Mechanics," "Pressure," and connections to educational initiatives like the "Student Learning Space."
  4. Licensing: The content on the website is licensed under the Creative Commons Attribution-Share Alike 4.0 Singapore License, emphasizing open access and sharing. However, commercial use of the EasyJavaScriptSimulations Library requires a separate license, details of which are provided.

Quotes:

  • "This virtual lab shows how an aerostatic balloon works. It is a nice example of application of the Archimedes' principle"
  • "The buoyant force (Fl) of the aerostatic baloon is obtained by heating air inside its cavity. The buotant force is due to the difference of density between the hot air inside and the cold air outside the balloon cavity."
  • "The air is a perfect gas. Therefore air density can be computed with the following equation : density=P/R*M /T."
  • "The standard atmosphere model from the surface to 11 km altitude is used to describe the variations of the temperature and pressure with altitude. This model states that the temperature decreases 6.5 K per Km (T=T0-6.5K/Kmh(km)) and the pressure follows the following equation: P=P0(T0/T(h))^-5.256."
  • "This simulation demonstrates Archimedes' Principle with a hot air balloon. The rising and falling of the hot air balloon is affected by the ambient temperature T0, the initial air pressure P0, and the mass of the hot air balloon m."
  • "Turning on the burner causes the hot air balloon to rise, turning the burner off causes it to descend."

Conclusion:

The "Hot Air Balloon JavaScript Simulation Applet HTML5" is a valuable open educational resource for teaching and learning about Archimedes' Principle, buoyancy, and the properties of gases. Its interactive nature, coupled with the underlying physics model based on the perfect gas law and the standard atmosphere, provides a hands-on approach to understanding the mechanics of a hot air balloon. The availability of the embed code and links to different versions enhances its utility for educators. The resource is part of a comprehensive collection of physics and mathematics simulations, indicating a strong commitment to open educational resources in these fields.

 

  • Hot Air Balloon Simulation Study Guide

    Key Concepts:

    • Archimedes' Principle: The buoyant force on an object submerged in a fluid is equal to the weight of the fluid displaced by the object. In the context of a hot air balloon, the "fluid" is the surrounding air.
    • Buoyant Force: The upward force exerted by a fluid that opposes the weight of an immersed object. For a hot air balloon, this force arises from the density difference between the hot air inside and the cooler air outside.
    • Density: Mass per unit volume. The simulation highlights how changing the temperature of the air inside the balloon affects its density.
    • Ideal Gas Law: Describes the relationship between pressure, volume, temperature, and the number of moles of a gas (PV = nRT). In this simulation's simplified model, it's represented in terms of density: density = P/(R*M*T).
    • Standard Atmosphere Model: A model that describes how atmospheric pressure and temperature change with altitude. The simulation uses this model up to 11 km.
    • Thermal Physics: The branch of physics that deals with heat and its relation to other forms of energy and work. The hot air balloon's operation is a direct application of thermal physics principles.
    • Thermodynamic Systems: Systems that can exchange energy (as heat and work) with their surroundings. The hot air balloon can be considered a thermodynamic system where heating the air changes its internal energy.
    • Heat Conduction: The transfer of heat through a material via direct contact of its molecules. While not the primary focus, heat transfer is relevant to maintaining the temperature difference in the balloon.
    • Newtonian Mechanics: The study of motion and the forces that cause it. The rising and falling of the balloon are governed by Newton's laws of motion, where the net force is the difference between the buoyant force and the balloon's weight.
    • Pressure: Force per unit area. Atmospheric pressure decreases with altitude, as described by the standard atmosphere model.

    Short-Answer Quiz:

    1. Explain the fundamental principle that allows a hot air balloon to float. How is this principle applied in the simulation?
    2. What causes the buoyant force on the hot air balloon in the simulation? Be specific about the properties of the air involved.
    3. Describe the relationship between the temperature of the air inside the balloon and its density, according to the model used in the simulation.
    4. What two atmospheric properties are modeled as changing with altitude in the simulation? Briefly state how each property changes.
    5. According to the simulation's description, what are the main factors affecting whether the hot air balloon rises or falls?
    6. What happens to the buoyant force on the balloon when the burner is turned on in the simulation? Explain why.
    7. The simulation uses the ideal gas law. In the context of the hot air balloon, what are the key variables in the density equation provided?
    8. How does the simulation account for the weight of the hot air balloon? What components contribute to this weight?
    9. The right graph in the simulation plots pressure and height against time. What do changes in the green line on this graph represent?
    10. Explain how the simulation demonstrates the application of Archimedes' Principle in a real-world scenario.

    Answer Key:

    1. A hot air balloon floats due to Archimedes' Principle, which states that the buoyant force equals the weight of the displaced fluid (in this case, air). The simulation demonstrates this by showing that when the buoyant force (due to the less dense hot air inside) is greater than the balloon's weight, it rises.
    2. The buoyant force on the hot air balloon is caused by the difference in density between the hot air inside the balloon's cavity and the colder, denser air outside. This density difference results in a greater upward pressure on the bottom of the balloon than the downward pressure on the top.
    3. According to the model, the density of air is inversely proportional to its temperature (density = P/(R*M*T)). Therefore, when the air inside the balloon is heated, its temperature increases, and its density decreases, making it lighter than the surrounding air.
    4. The two atmospheric properties modeled as changing with altitude are temperature and pressure. The model states that temperature decreases by 6.5 K per kilometer of altitude, and pressure decreases according to the provided exponential equation involving the changing temperature.
    5. The rising and falling of the hot air balloon are primarily affected by the ambient temperature (T0), the initial air pressure (P0), and the total mass (m) of the hot air balloon (including the balloon itself, ballast, and people).
    6. When the burner is turned on, it heats the air inside the balloon, causing its temperature to increase and its density to decrease. This decrease in internal air density increases the density difference between the inside and outside air, resulting in a larger buoyant force acting upwards on the balloon.
    7. In the density equation provided (density = P/(R*M*T)), the key variables are P (air pressure), R (the ideal gas constant), M (the molecular weight of the air), and T (air temperature).
    8. The simulation accounts for the weight of the hot air balloon as 'w', which is compensated by the buoyant force (Fl). This weight includes the weight of the balloon itself, any ballast (wl), and the weight of people on board.
    9. Changes in the green line on the right graph represent the changes in the hot air balloon's height over time. An upward slope indicates the balloon is rising, a downward slope indicates it is descending, and a horizontal line indicates it is at a constant altitude.
    10. The simulation demonstrates Archimedes' Principle by allowing users to observe how heating the air inside the balloon (thus changing its density and the weight of the displaced air) directly affects the buoyant force and consequently the motion (rising or falling) of the balloon.

    Essay Format Questions:

    1. Discuss the role of density in the operation of a hot air balloon. Explain how the simulation models changes in air density and how these changes lead to the balloon's movement.
    2. Analyze the assumptions made in the simulation's model, specifically the perfect gas law and the standard atmosphere model. How do these assumptions simplify the real-world physics of a hot air balloon? What are potential limitations of these simplifications?
    3. Explain how the hot air balloon simulation effectively demonstrates Archimedes' Principle. Use specific examples from the simulation's description to support your explanation.
    4. Describe the interplay between the buoyant force and the weight of the hot air balloon in determining its vertical motion. How can the simulation be used to explore the conditions necessary for ascent, descent, and maintaining a constant altitude?
    5. Considering the provided information, discuss the potential educational value of the hot air balloon JavaScript simulation applet for students learning about thermal physics and fluid mechanics concepts. What specific learning goals could this simulation help achieve?

    Glossary of Key Terms:

    • Aerostatic Balloon: A balloon that achieves buoyancy in the air through the heating of the air inside its envelope, reducing its density compared to the surrounding air.
    • Archimedes' Principle: A fundamental principle of fluid mechanics stating that the upward buoyant force that is exerted on a body immersed in a fluid, whether fully or partially submerged, is equal to the weight of the fluid that the body displaces.
    • Buoyant Force (Fl): The upward force exerted by a fluid that opposes the weight of an immersed object. In the case of a hot air balloon, it's the upward force resulting from the displacement of the cooler, denser outside air by the hotter, less dense air inside.
    • Density: The mass of a substance per unit of volume, typically expressed in kilograms per cubic meter (kg/m³).
    • Ideal Gas: A theoretical gas composed of many randomly moving point particles that are not subject to interparticle interactions. The simulation assumes air behaves as a perfect gas.
    • Perfect Gas Law: An equation of state of a hypothetical ideal gas, usually written as PV = nRT, where P is pressure, V is volume, n is the number of moles, R is the ideal gas constant, and T is temperature. In the simulation, it's used to compute air density.
    • Standard Atmosphere Model: A vertical profile of Earth's atmosphere of how pressure, temperature, density, viscosity, and other properties change over a wide range of altitudes. The simulation uses this model up to 11 km.
    • Temperature (T): A measure of the average kinetic energy of the particles in a substance, often measured in Kelvin (K) in scientific contexts.
    • Pressure (P): The force exerted per unit area, often measured in Pascals (Pa).
    • Weight (w): The force exerted on an object due to gravity, typically measured in Newtons (N). In the context of the balloon, it includes the weight of the envelope, payload (people), and ballast.
    • Ballast (wl): Material carried by a balloon to provide stability or to be released to make the balloon lighter and ascend.
 

Sample Learning Goals

[text]

For Teachers Aerostatic Balloon

This simulation demonstrates Archimedes' Principle with a hot air balloon. The rising and falling of the hot air balloon is affected by the ambient temperature T0, the initial air pressure P0, and the mass of the hot air balloon m.

The left graph of the simulation shows the actual hot air balloon. The right graph plots the graph of pressure (blue) and height (green) against time.

Turning on the burner causes the hot air balloon to rise, turning the burner off causes it to descend.

Research

[text]

Video

[text]

 Version:

  1. http://weelookang.blogspot.com/2018/05/hot-air-balloon-javascript-simulation.html
  2. http://www.euclides.dia.uned.es/simulab-pfp/curso_online/cap7_caseStudies/sec_balloon.htm by Alfonso Urquia and Carla Martin-Villalba

Other Resources

[text]

Frequently Asked Questions: Hot Air Balloon Simulation

What is the purpose of the Hot Air Balloon JavaScript Simulation Applet?

This virtual lab is designed to illustrate how an aerostatic balloon operates. It serves as a practical demonstration of Archimedes' principle, showing how a hot air balloon can rise and fall by manipulating the buoyant force.

How does a hot air balloon generate buoyant force in this simulation?

The buoyant force is created by heating the air inside the balloon's cavity. This heating reduces the density of the air within the balloon compared to the cooler, denser air outside. The difference in density results in an upward buoyant force, as explained by Archimedes' principle.

What physical principles are modeled in this simulation?

The simulation primarily models Archimedes' principle, the ideal gas law (used to calculate air density based on pressure and temperature), and a standard atmospheric model that describes how temperature and pressure change with altitude up to 11 km.

What are the key variables that affect the hot air balloon in the simulation?

The behavior of the hot air balloon is influenced by several factors that can be adjusted or observed in the simulation. These include the ambient temperature (T0), the initial air pressure (P0), and the total mass of the balloon (m), which includes the balloon itself, ballast, and people. The burner's operation (on or off) directly controls the temperature of the air inside the balloon, thus affecting its buoyancy.

How does the simulation model the change in atmospheric conditions with altitude?

The simulation incorporates a standard atmospheric model that assumes air temperature decreases linearly with altitude (6.5 K per kilometer) up to 11 km. It also models the decrease in air pressure with altitude according to a specific equation that depends on the temperature profile. These models provide a realistic environment for the balloon's operation at different heights.

What visual feedback does the simulation provide?

The simulation features a visual representation of a hot air balloon on the left side. On the right side, it includes a graph that plots pressure (blue line) and height (green line) against time, allowing users to observe how these parameters change as the simulation progresses.

How can users interact with the simulation to observe the hot air balloon's behavior?

Users can interact with the simulation by controlling the burner. Turning the burner on increases the temperature of the air inside the balloon, leading to a decrease in density and an increase in buoyant force, causing the balloon to rise. Turning the burner off allows the air inside to cool, increasing density and causing the balloon to descend as the buoyant force decreases.

Who are the creators and contributors to this Hot Air Balloon JavaScript Simulation Applet?

The simulation was authored by Carla Martín from the Dpto. de Informática y Automática, E.T.S. de Ingeniería Informática, UNED, Madrid, Spain. Credits also go to Tan Wei Chiong and Loo Kang Wee for their contributions.

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Parent Category: 02 Newtonian Mechanics
Category: 06 Pressure
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