Home School Life Journal From Preschool to High School

Home School Life Journal ........... Ceramics by Katie Bergenholtz
"Let us strive to make each moment beautiful."
Saint Francis DeSales

The Coanda Effect

One Candle
One rectangle such as a small box We used a square glass canister and a bar of soap.
One cylinder such as a can  We used an oatmeal box and a vase.

Put a candle behind a box and try and blow it out.
First we used a rectangular glass canister.
The flame flickered but no one could blow it out.

Repeat the experiment, but this time use a round can. I only caught it before he actually blew it out, but he did blow it out pretty easily.

The boys decided to try a thinner container to see if the results were different.

We had a hard time finding something that was thin and rectangular. We finally found a bar of laundry soap. It was so short, I was afraid that it wouldn't work, but it did. They were unable to blow it out.
Then we used a tall cylindrical vase. It blew out just like we thought it would.

So what is happening in this experiment?
It is called "The Coanda Effect" because in the 1930’s a man named Henri Marie Coanda discovered that a fluid has a tendency to follow a curved surface. He later used this in the design of an airplane that would utilize this “Coanda effect” to its greatest potential.



  1. I have this experiment in a very old Easy Physics Experiments book - I've been meaning to do it with the girls...

    I have so much meaning. ;)

  2. The nice thing about this one is that it only takes 5 minutes!


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