First, I wrapped a rubber band around a book, and attached a bungee cord to it. I then measured the length of the bungee cord with no tension on it. It was 11 in. Then, I stretched the bungee cord until the book began to move. I measured how far this was. This measurement was 16 inches. Next, I put down skewers on the table, and put the book on top of that. This time, when I dragged the book, the bungee cord did not stretch at all, and it was much easier to move the book. This works because the friction in between the book and the skewers is significantly less then the friction between the book and the table.
This method was used by the Egyptians to contruct buildings, especially the pyramids.
You can see a picture of it below.
For my second experiment, I investigated Galileo's Law of Falling Bodies. People used to believe that objects fall at a constant rate, in relation to their weight. Galileo proved, however, that objects accelerate, and their speed has nothing to do with their weight. He used an inclined plane to prove this, and I did a similar experiment. I put some books under one end of a coffee table, to give it a slant, then taped down some pieces of string about 20 CM apart. Next, I rolled a marble down the table, across the strings. You could hear it clicking as it bumped over each string. The interesting thing is, the clicks became close and closer together. This proves that the marble is accelerating. I recorded this sound, and I have posted an image of the waveform below.
You can see that each click getting closer and closer together. Also, I have uploaded a picture of the whole setup below.
The second part to this experiment was to try to set the strings the right distance apart so the marble made a consistant clicking sound.
I uploaded the waveform of this experiment, and the picture of the sting setup, as well.
