Cohesion & Adhesion

Today in class, we didn't have much to do. We are now on a topic about water and solutions. Mr. Olson used the powerpoint and some animations to let us understand the things more. I understand most of them but I still get confused about the bonds sometimes.

The good thing was that we could do kind of an experiment after this powerpoint. We gonna dropped some water on a penny and also tried to put a paper clip on the water. We had to find out how many drops the penny could hold and also see if the paper clip would float on the water.

Before this little experiment, I guessed that the penny could hold ten drops of water. I thought I would guess wrong because most of the classmates guessed something about three drops. Oh! What a surprise! The penny could totally hold 25 drops. It really shocked me that the tiny little penny could hold such an amount of water. And when Mr. Olson came by my lab station, he used a normal finger and a soapy finger respectively to poke the water on the penny. It surprised me again when I saw that the water poked by the normal finger didn't have much difference while that poked by the soapy finger immediately broke apart. It was really amazing. Mr. Olson said that the reason for this was because of the surface tension on the water surface. Clearly, the soap broke the surface tension.

Well, for the paper clip, I was not successful to make it float on the water. But I was lucky to see one of my friends do it. I think I will try it again if I have the chance.

Time passed by really fast, I was in a hurry to pack away my things when the bell rang. But I was still in deep thought of the interesting experiment after class.