HOT AIR BALLOON ------- Interactive Physics Simulation ------- Page 01
How do you control a hot air balloon? A hot air balloon floats because atmospheric pressure is greatest closer to the ground. The small difference between the pressure at the top and bottom of an object generates a net upward force. We don't usually notice the upward lift force we all feel due to this phenomenon. By lowering the density - and therefore the weight - of the hot air in the balloon, the balloon and its passengers can rise upward. We accomplish this by heating the air. To access this physics simulation visit: http://goo.gl/jfr7q4 Page 02
Vent - This slider opens a vent at the top of the parachute. Hot air escapes from the balloon and cold air enters through the bottom. This has the effect of increasing the overall weight of the balloon, because more slow-moving cold air particles are required to support the volume of the balloon against atmospheric pressure. The volume of the balloon determines the lift force - since this remains roughly the same, more cold air creates a net force downward. Burner - This slider turns the burner on which increases the amount of hot air in the balloon. This has the effect of reducing the overall weight of the balloon, because fewer fast-moving hot air particles are required to support the volume of the balloon against atmospheric pressure. The volume of the balloon determines the lift force - since this remains roughly the same, more hot air creates a net force upward. Payload Mass - This slider adjusts the mass of the payload - in particular, the number of passengers. You can only change the number of passengers safely when the payload is on the ground, so this slider is inoperable in flight. A greater mass will mean the system will react more slowly to a net force, in agreement with Newton's 2nd Law, which states that acceleration is the net force divided by the inertial mass. To access this physics simulation visit: http://goo.gl/jfr7q4 Page 03
Velocity vs Time - This is a graph of the vertical velocity of the hot air balloon as it varies with time. The slope of the graph represents the acceleration of the system - this can be determined from Newton's 2nd Law as the ratio of net force to mass: greater upward net force, greater upward acceleration, greater slope of velocity vs. time graph. Altitude vs Time - This is a graph of the vertical position of the hot air balloon as it varies with time. The slope of the graph represents the velocity of the system - greater slope means the velocity is higher. As the slope decreases to zero, this means the balloon is coming to a stop. The curvature of this graph represents the acceleration of the system - the curvature is highest when the net force is highest. To access this physics simulation visit: http://goo.gl/jfr7q4 Page 04
Adjust the sliders so that the hot air balloon reaches a maximum upward velocity of 2.5 m/s.( Hint: Adjust the burner slider and payload mass slider so that the hot air balloon reaches a maximum velocity of +2.5 m/s). Adjust the sliders so that the hot air balloon reaches maximum downward velocity of 0.5 m/s.(adjust the burner slider and payload mass slider so that the hot air balloon reaches a maximum velocity of -0.5 m/s). Adjust the sliders so that the hot air balloon reaches maximum altitude of 5.54 m.( Adjust the burner slider and payload mass slider so that the hot air balloon reaches a maximum altitude of 5.54 m, as shown on the Altitude vs Time graph). To access this physics simulation visit: http://goo.gl/jfr7q4 Page 05
Challenge ME! How is it different flying the balloon with more or fewer passengers? Can the balloon still be flying upward even if its weight is greater than the buoyant force? Can you land the balloon while accelerating upward? Need Help? Check out the Hot Air Balloon Walkthrough video at: https://youtu.be/6mie_iroiwc To access this physics simulation visit: http://goo.gl/jfr7q4 Page 06
What is the difference between a hot air balloon and a blimp? A hot air balloon can control its altitude, but does not move on its own along the ground. The way a hot air balloon pilot moves from one location to another is that he or she is well aware of the direction the wind is blowing at different altitudes. With a blimp, you can use blowers to generate thrust in the direction you want to go. Who holds the altitude record for a hot air balloon? Vijaypat Singhania of Mumbai, India, flew to an altitude of 21 km in a hot air balloon in 2005. It is possible to achieve even higher altitude using helium balloons. Does a submarine work in a similar way? Yes! The air in a submarine is much less dense than water, and so the submarine has no problems floating to the surface. What allows a submarine to submerge is water that it pumps onboard into ballast tanks. This water weighs the submarine down and allows it to dive. When was the first hot air balloon launched? Would you believe that the first hot air balloon was launched in Paris, France, as long ago as 1783? This was the first hot air balloon that flew 'on its own' without a rope tethering it to the ground. It wasn't until much later - 1960 - when the first hot air balloon that carried its own burner to heat air was launched. To access this physics simulation visit: http://goo.gl/jfr7q4 Page 07
Physics Concepts Click on the link below to learn more. Newton's Second Law - http://www.ck12.org/physics/newtons-second-law/ Newton's First and Second Laws - http://www.ck12.org/physics/newtons-first-and-second-laws/ To access this physics simulation visit: http://goo.gl/jfr7q4 Page 08