We had great fun yesterday finding out how many drops of water would fit onto a 5 cent piece. As with our O-Wing glider experiment, we realised different variables would affect this test:
- how hard we pushed the pipette to create the drops
- the angle we held the pipette
- which side of the coin we used
- whether the coin was dirty or new
- how close we held the pipette to the coin
- the person holding the pipette and making the drops would need to remain the same for each test.
We began by estimating how many drops we thought we might be able to fit onto the coin. Most of the children predicted less than 5 drops. Some children predicted less than 10, while a few brave children predicted the coin might be able to hold 20 drops!
There was great excitement when we began our experiment and the children discovered that the coin could actually hold many more drops of water than 20! Our champions (2 groups), managed to get 97 drops onto their coin!
- water is strongly attracted to itself, resulting in a very strong surface tension
- the outcome of an experiment can be influenced by many variables.