Monday, 21 April 2014

Quite the contrary - Sink or Float?

This is amongst the earliest and the simplest experiments that you can try with kids - even 2 year olds! Unlike my other experiments, this doesn't involve colours, but involves water, which is again a crowd puller ;-)

The experiment basically introduces the kids to weights, buoyancy, density. Though these words don't really have to be put across to the kids, what they do understand is objects float when they are light and sink if they are heavy. The fun part of the experiment is you can send your kid on a hunt around the house to look around for tiny objects to use in the experiment - they could be just about anything. The more, the merrier! Secondly, before you drop any object in the water, you can let your child guess what would happen and why. If you want to make it a little more of a scientific project with an older child, you can actually take a paper and pen and record your observations!

We first took a large bowl and filled it with water. I then placed 2 smaller empty bowls on either side and put cards next to each of them that said 'SINK' and 'FLOAT' respectively.

I then arranged all the items that A and I had hunted for around the house for dunking  in the water for this activity.

As you can see, we picked stuff like an earring to a balloon to balls to erasers; we even took spoons of wood, plastic and steel.A tiny glass bottle, a straw, a grape - like I said, just about anything is okay. I was careful to not take any object that would absorb - I decided that could be a separate experiment; I did not want to confuse her with that learning here. 

One by one, we started dropping the objects in the water. Before she dropped it in the water, A would take a guess at what would happen, whether it would sink or float. 

The confusion for A came in when we put 2 little balls together - one was plastic and one was a bouncy ball - the plastic one floated and the other sank. She just couldn't explain how and my husband and I had a nice laugh at her amazement. 

As adults, it is very easy for us to explain this phenomena. But for kids who associate things with big and small, it is tough for them to understand why a small grape would sink to the bottom and a huge, plastic capsicum toy would float! 

There was some learning for us too - a pistachio shell, which we thought would float, actually sank! 

A also noticed the refraction of light on this hanger, how it looks bigger inside the water than outside. 

Once all observations were made and the idea was explained, I asked A to pick out the stuff from the water and sort them in the respective bowls. 

We noticed that A was still a little confused, especially with objects that are bigger in size, but lighter. It became a game with us in the coming days, where we would look at or hold  different objects and try to guess if it would sink or float in water. 

And when the experiment time was over, we let A play with objects and the water by herself for a while. She  was at it for a while and when the entire table area was flooded, it was time for me to play bad mommy and end the revelry! 


  1. Clever post for Q quite the contrary is a great idea. I worked with younger kids years (in the USA and SWEDEN) ago and the sink or float was always popular on both sides of the pond. #AtoZchallenge ☮Peace
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  2. Have you considered teaching as a profession? I am serious...

  3. I agree with Aarthi ... you are a wonderful teacher :-)