Let’s say you released a small stone and a feather from a certain height, what are you likely to observe?

Obviously, the stone will hit the ground first. Given this day-to-day experience, it is not very surprising that a lot of children and even adults think that the heavier objects fall faster. We also learn (many a time just mug it up) that the acceleration due to gravity on the surface of the Earth is constant. Clearly, the day-to-day experiences overpower our knowledge about the acceleration due to gravity.

One very powerful way to make sure learners (children and adults) ‘understand’ the nature of falling objects would be to actually demonstrate that the two objects of different masses fall together. This is exactly what following two examples have done –

During Apollo-15 mission to the Moon, astronauts conducted an experiment on the surface of the Moon using a feather and a hammer. Here is the video link to that –


Brian Cox used world’s biggest vacuum chamber for the same demonstration as part of Human Universe series on BBC-

Now, as an educator, it is not possible to create such a large vacuum chamber or go to the Moon for one demonstration! We can show these videos, but even more compelling demonstration would be where learners (students and adults) can participate in it. As it must be clear by now that presence of air on the surface of the Earth spoils all the possibilities of actually demonstrating what above two videos have done. But there is a possible way around it, if we use two objects that have the same shape but different masses. This is exactly two educational specialist at EI tried a few years ago.

Nishchal and Anar (Educational specialist at EI) used a book and a brick for this demonstration.

Here is another similar video Derek Muller, who uses two balls of the same shape but different masses for his demonstration

As it must have been clear from the last video that such participatory demonstrations do create an impact on the learners by challenging their existing believes/conceptions. Would it work for other conceptions as well? What are the possible limitations of this approach? Do share your thoughts with us and rest of the reader community in the comments section below.


 By Anagh Purandare, Educational Specialist

Anagh Purandare

Anagh Purandare is an Education Specialist at Educational Initiatives. He is a science student by training, and passionate about science education. He enjoys asking questions and finding answers to them as he thinks asking questions as one of the first steps of doing science. The purpose of his blog posts is to generate discussion on some such questions. He believes that discussions lead to better understanding of the issue. When he is not working, he enjoys travelling, reading and eating tasty food. He particularly enjoys debates on political and social issues.