11:15 AM - 11:30 AM
[O08-05] Mars gravity created using a variable gravity apparatus
~Comparing crater formation experiments~
★Invited Papers
Keywords:Variable Gravity Apparatus, Mars, The Science Club in "Teijisei" High School
Three “Teijisei” high schools in Osaka each have their own variable gravity apparatus. The part-time science club at Higashi-Shinjuku “Teijisei” High School in Tokyo (the setting for the NHK drama series ‘Sora Wataru Kyoshitsu’ - a fictional high school) also has a variable gravity apparatus. We will compare and examine the variable gravity apparatus in Osaka and Tokyo, as well as the bullet launchers used to create craters. By doing so, we hope to identify the problems with the apparatus and lead to future improvements. The variable gravity apparatus uses Atwood's pulley. The weight of the ascending capsule and the descending capsule is adjusted to create the desired gravity (0G: microgravity to 1G: terrestrial gravity) inside the descending capsule. The height of the apparatus is about 2.5m.
The science clubs at Kasugaoka, Otemae and Higashi-Shinjuku used bicycle wheels as pulleys. The wheels were approximately 60cm in diameter. The ceiling height at Imamiya was low, so they used two small pulleys (8cm in diameter) fixed at a distance of 1m apart, and attached a wire to them.
The duration of the gravity of Mars was approximately 0.6 seconds at the Kasugaoka, Otemae and Higashi-Shinjuku science club. At the Imamiya, where the apparatus was slightly lower, the duration was just over 0.4 seconds.
The time course of the gravitational acceleration produced by the variable gravity apparatus at the Higashi-Shinjuku Science Club is ideal. There is no vibration immediately after the fall, and even after reaching the gravity of Mars, the variation in gravitational acceleration is small and stable. At the variable gravity apparatus at the Osaka Science Club, there is still vibration in the gravitational acceleration. Vibration occurs when the capsule leaves the electromagnet immediately after the fall. Vibration occurs in the pulley attachment part and in the descending capsule itself during the fall. In order to reduce this, we have reinforced the pulley attachment part and the descending capsule. We have also continued to design and improve devices that reduce vibration when the capsule leaves the electromagnet. At present, we are continuing to make adjustments by changing the method to one where the ascending capsule is held in place by rubber tyres. It is said that the vibration was reduced by changing from a human hand to an electromagnet at the Higashi-Shinjuku Science Club. However, at present, the method that can suppress vibration the most is to support and release the ascending capsule by hand.
In addition, the capsule and wires of the Higashi-Shinjuku Science Club are connected in a way that balances them at four points in the four corners at the top. The capsule of the Osaka Science Club is connected at a single point in the center, so the issue was the wobbling of the capsule during the experiment. We would like to conduct an experiment to see if the four-point balancing method reduces vibration.
For the bullet ejection device, Otemae Science Club used a commercially available electric gun. When the inside of the descending capsule reached Martian gravity, the bullet was fired by turning on the trigger contact attached to the electric gun in the descending capsule. The lead wire from the trigger contact of the electric gun was set on both ends of a clothes peg. This clothes peg was used to clamp a rod that stuck out from the ceiling in a downward direction. When the falling capsule reaches the position where it is under the gravity of Mars, the clothes peg comes off the stick and the lead wire make contact, firing the bullet. The Higashi-Shinjuku Science Club prepared an apparatus with a spring inside the tube. The mechanism for firing the bullet when it reaches the gravity of Mars is almost the same as that of the Otemae Science Club. In order to fire the bullet downward, a mechanism is needed to prevent the bullet from falling. The details are unknown.
Although the specifications of the variable gravity apparatus differ from school to school, they are all able to produce a stable Martian gravity. There is a pressing need to improve the apparatus to suppress vibration immediately after the fall.
The science clubs at Kasugaoka, Otemae and Higashi-Shinjuku used bicycle wheels as pulleys. The wheels were approximately 60cm in diameter. The ceiling height at Imamiya was low, so they used two small pulleys (8cm in diameter) fixed at a distance of 1m apart, and attached a wire to them.
The duration of the gravity of Mars was approximately 0.6 seconds at the Kasugaoka, Otemae and Higashi-Shinjuku science club. At the Imamiya, where the apparatus was slightly lower, the duration was just over 0.4 seconds.
The time course of the gravitational acceleration produced by the variable gravity apparatus at the Higashi-Shinjuku Science Club is ideal. There is no vibration immediately after the fall, and even after reaching the gravity of Mars, the variation in gravitational acceleration is small and stable. At the variable gravity apparatus at the Osaka Science Club, there is still vibration in the gravitational acceleration. Vibration occurs when the capsule leaves the electromagnet immediately after the fall. Vibration occurs in the pulley attachment part and in the descending capsule itself during the fall. In order to reduce this, we have reinforced the pulley attachment part and the descending capsule. We have also continued to design and improve devices that reduce vibration when the capsule leaves the electromagnet. At present, we are continuing to make adjustments by changing the method to one where the ascending capsule is held in place by rubber tyres. It is said that the vibration was reduced by changing from a human hand to an electromagnet at the Higashi-Shinjuku Science Club. However, at present, the method that can suppress vibration the most is to support and release the ascending capsule by hand.
In addition, the capsule and wires of the Higashi-Shinjuku Science Club are connected in a way that balances them at four points in the four corners at the top. The capsule of the Osaka Science Club is connected at a single point in the center, so the issue was the wobbling of the capsule during the experiment. We would like to conduct an experiment to see if the four-point balancing method reduces vibration.
For the bullet ejection device, Otemae Science Club used a commercially available electric gun. When the inside of the descending capsule reached Martian gravity, the bullet was fired by turning on the trigger contact attached to the electric gun in the descending capsule. The lead wire from the trigger contact of the electric gun was set on both ends of a clothes peg. This clothes peg was used to clamp a rod that stuck out from the ceiling in a downward direction. When the falling capsule reaches the position where it is under the gravity of Mars, the clothes peg comes off the stick and the lead wire make contact, firing the bullet. The Higashi-Shinjuku Science Club prepared an apparatus with a spring inside the tube. The mechanism for firing the bullet when it reaches the gravity of Mars is almost the same as that of the Otemae Science Club. In order to fire the bullet downward, a mechanism is needed to prevent the bullet from falling. The details are unknown.
Although the specifications of the variable gravity apparatus differ from school to school, they are all able to produce a stable Martian gravity. There is a pressing need to improve the apparatus to suppress vibration immediately after the fall.