Thursday, 28 May 2015

Investigating Viscosity

Today we did another investigation about the viscosity of different liquids. 

Last time we dropped a marble into the liquids, but we found that timing accurately was really difficult because the marble fell through some of the liquids very quickly.

We talked about how we could change the investigation, perhaps gaining more accurate results.  One of our ideas was to use a lighter object as we thought that it would travel through the liquid more slowly.

So, we have tested our prediction using a dice instead of a marble.

Here are some photos

We took turns pouring liquids, dropping the dice, timing the fall and taking photographs.

Here are some videos of us doing our Science work:

Here is a table of 4Bs results.  You can see the difference in the timings between dropping the marble and the dice.

We calculated that the dice fell about 3 times slower in thicker liquids like shower gel and washing up liquid but took about twice the time to fall through thinner liquids like oil, lemonade and orange!  We are still discussing the milk result... Why is it 3 times (it is thin like water)?  Did we test this accurately enough?

Whatever our decision about the milk, in Year 4 we have concluded that lighter objects fall slower than heavier objects through all liquids.

(We didn't test the ketchup because the marble is still sitting on top of the liquid after the first investigation - so we knew a lighter one would not be any different!)

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