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Gravity – Air = Video Gold. To demonstrate the effects of air — not gravity — on falling objects, physicist Brian Cox of the BBC Two program. Free-fall physics science project: Investigate whether a heavier object falls faster than. Basic understanding of gravity. Standing on a balcony near the top of the Tower of Pisa in Italy, a young scientist dropped two balls into the crowd below.
. Friction.This is a simple demonstration that can foster discussion of many physics topics.Begin by standing on a desk, holding a book and an open piece of paper. Ask 'which will hit the ground first if I drop them?' Typically, students will answer the book.
![Acceleration Acceleration](http://i.ytimg.com/vi/BF2Ic50m7kQ/maxresdefault.jpg)
Ask why, the answer you will probably get is because 'the book is heavier.' Then, crumple up the paper (usually to remarks such as 'cheater') and drop them. Some follow up questions might be. Does crumpling the paper add mass to it?. When the paper is not crumpled does its mass make it fall faster?.
What makes the paper fall more slowly when it is not crumpled? (Note here you are leading students thought toward air resistance). What force makes things fall toward the ground?This demonstration can be followed up with discussions on Terminal Velocity to talk about balanced and unbalanced forces.This can also be followed up with a discussion of projectile motion with the classic question:'If a bullet is shot forward parallel to the ground without anything in its way, and at the exact same moment another bullet is dropped from the same height, which bullet will hit the ground first?' (Both bullets hit the ground at the same time since gravity is the only force pulling them down)Projectile Motion Demonstration. Set-up two pennies and a ruler on a table as in the picture below. Hit the ruler as shown, watch and listen to which penny falls first. (both should hit the ground very close to the same time).
Students know when an object is subject to two or more forcesat once, the result is the cumulative effect of all the forces.2d. Students know how to identify separately the two or more forcesthat are acting on a single static object, including gravity, elasticforces due to tension or compression in matter, and friction.2g. Students know the role of gravity in forming and maintainingthe shapes of planets, stars and the solar system.Physics1f.
![Which ball will hit the ground first Which ball will hit the ground first](http://cdn.c.photoshelter.com/img-get/I0000m26oou9LlL8/s/860/860/Fphoto-28109011K-2RM.jpg)
【References】Chinese Journal Full-text Database3 Hits1JI Ming-rong;WANG Xin-chun;WANG Kun-lin;SI Min-zhen(Department of Physics and Electronic Science,Chuxiong Normal University,Chuxiong 675000,China);J;Journal of Chuxiong Normal University;2013-032WANG Xiao-bing;CHEN Man;ZHU Fei-xia(Department of Physics and Electronic Science,Chuxiong Normal University,Chuxiong 675000,China);J;Journal of Chuxiong Normal University;2013-033LEI Da,MENGGEN Qi-qi-ge,LI Shu-xia,ZHOU Xiao-juan(Ordos College of Inner Mongolia University,Inner Mongolia Ordos 017000);J;Physical Experiment of College;2013-04. 【Co-references】Chinese Journal Full-text Database10 Hits1YU Xiao-ming1,CUI Yi-he2,CHEN Fei3, HU Guo-qing3(1. Department of Basic Courses, Yancheng Institute of Technology, Yancheng, Jiangsu 224051, China;2. Department of Experiments, Yancheng institute of Technology, Yancheng, Jiangsu 224051, China;3.
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