Thursday, February 15, 2018

Don't be so DENSE!

In Rm 22, we are always up for learning more about the world around us, and some of the physical laws that govern the universe.

This week, we have been learning about DENSITY, which is the relationship between an object's volume (the amount of space it takes up) and its MASS (which is its, er...MASS). Floating and sinking depends on the density of the medium in which you place something into, and the density of the thing you are placing! (Simple, right?)

Since water has a specific density (1.025 kg/L), an object with a lesser density will float if placed into it. If it is more dense than the water, it sinks. Incidentally - to physicists, they make no distinction between liquids and gases when it comes to floating and sinking. They sometimes refer to us as living at the bottom of an ocean of atmosphere! 

Anyway, the students worked with lumps of plasticene and discovered that a lump of plasticene sinks like a rock, but if you alter its overall density by increasing the volume of the shape by making it into a boat shape, it will float. This is how battleships made from steel can float. They have a large volume, they are filled with air, and their mass is spread out over the larger volume. 

The children had a lot of fun making their boats float, and then tested their carrying capacity by weighing them down with wooden blocks. Shreya and Alka managed to make a boat that carried 34 blocks! Not bad girls - maybe you should consider engineering as a future career?

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