It is so annoying when get to the end of a ketchup bottle and you have to keep banging to get that last bit out. Why is this? Because ketchup is thick and does not flow as easily as other fluids. We call this resistance to flowing viscosity.
The rate at which different fluids flow can vary considerably.
So how about having races to test them!
What you will need:
Stop watch/tape measure
A ramp – we used a table that we took two legs off.
Different fluids to test
We used whole milk, ketchup, chocolate sauce, orange juice and cooking oil
Deciding what to measure
- you could decide to time how long it takes for all five fluid to reach the bottom of the table
- you could decide to measure how far they have travelled after a certain time
How to make the test fair
You need to consider the things that could impact on it not being a fair test – this could include things like
- ensuring the volume use use is the same for all fluids
- ensuring that you time the flow for the same distance
- ensuring that measure after a set time for each.
- ensuring you repeat the investigation 3 times and take a mean result
- The gradient of the ramp is the same for each fluid
You can either do one at a time – this is easier for recording time, or tip them all at the same time if you want them to get to the bottom of the table.
Let them flow for the set time you have decided, or time them until they all reach the bottom.
You can record your results in a table.
We decided to wait until they got to the bottom, but had to stop the experiment as it was clear the ketchup was never going to make it! Next time we will try with measuring the distance travelled!