Sample Puzzler & Write-up

Funny Funnel

If you have tried transferring a liquid into a bottle through a funnel, you may have noticed that you have to lift the funnel from time to time when the liquid collects in the funnel and does not flow down. Try it at home. It doesn’t always do that but some times it does.

The question is: why does it do that?

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Two sample solutions/write-ups are provided below to show you that there isn’t necessarily just ONE single correct wording for a solution.

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SOLUTION 1

Humpty Dumpty
Mr Gurung
Science M2/3
Date

Funny Funnel

The Problem:
Funnels are used to transfer liquid from one container to containers with small opening such as a bottle.  When transferring the liquid however, the water collects in the funnel and does not flow continuously and smooth.  The funnel then has to be lifted from time to time. Why does the liquid collect in the funnel?

The Solution:
Empty containers contain air.  When putting something else inside the container, the air has to be able to escape. Generally the air easily escapes into the atmosphere. However, if there is no outlet for the air to escape, the air gets trapped and cannot escape.

What happens here is that the air inside the bottle gets trapped.  When the water is poured into the bottle using a funnel, the water initially goes into the bottle.  But not for long as the mouth of the bottle is completely sealed by the funnel and the water. The air inside the bottle is then unable to escape preventing the water from flowing into the bottle.

So, the reason the water does not flow and collects in the funnel is because the trapped air prevents it.

 

[You could have included a schematic diagram illustrating the process.]

[If you received help you must in-text reference the materials and cite it here.]

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SOLUTION 2

Humpty Dumpty
Mr Gurung
Science M2/3
Date

Funny Funnel

The Problem:
I have noticed that when pouring a liquid into a bottle using a funnel, the liquid does not flow into the bottle smoothly and continuously. I have to lift the funnel from time to time to allow the liquid collected in the funnel to flow into the bottle before I can add more liquid to the funnel. Why does the liquid collect in the funnel and not flow continuously into the bottle?

The Solution:
I know that, though we cannot see it, all empty containers are filled with air.  When the empty container is filled with something else, we are basically replacing the air with it. But for that to be possible, the air must create space.  Generally, the air escapes and creates space for the other thing through different openings in the container.  However, if there is no outlet for the air to escape, the air gets trapped and cannot escape.

When transferring water into a bottle using a funnel, the air inside the bottle gets trapped.  The water initially goes into the bottle without any problem.  But when the bottle is filled with some water, as the mouth of the bottle is completely sealed by the funnel and the water in the funnel, the air inside is unable to escape, preventing additional liquid from flowing into the bottle. Lifting the funnel allows the air to escape from the sides of the funnel allowing the water to once again flow into the bottle.

So, the water does not flow and collects in the funnel because the trapped air prevents it.

 

[You could have included a schematic diagram illustrating the process.]

[If you received help you must in-text reference the materials and cite it here.]

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