Class 9/2/09

Today we had a double period. During the first period we had our first assessment. In the second period we started the "Engineering a 'Photo Finish" Lab. In class we completed Part A and for homework we have to do Part 2 through question 11. For Part A we were introduced to a new more expensive type of buggy, a car on a ramp. We had to position the ramp so that the buggy and the car reached the end of the ramp at the same times. Then we found the velocity of the buggy and graphed it on a position versus time graph. Next we guessed what the position versus time graph would look like for the car and graphed it on the same axis as the buggy. Finally we used Logger Pro and the motion detector to find more exact data on the velocity of the car. We need that data to complete the homework.

Tuesday's Class

In class today, we measured the speed of a toy car. First, we measured the time it took for the car to go distances of 0.5, 1.0, and 1.5 meters. Then each group had to make a prediction for what the speed was going to be if we ran a trial of 2.0 meters using the previous data and setting up an equation. You had to get the slope of the information. The change in meters over the change of time. My group found that our prediction was correct and our actual results were only milliseconds off. We then measured how long the car has been traveling at different times. We found the average velocity of the car by getting the slope of the graph. We then wrote an equation to find the position of the car at any given time. This was the same equation as the slope formula. Lastly, there was a problem to find out how long it would take the car to get from Atlanta to San Diego, which is around 3,000 miles. It would take a really long time.

Thursday's Class

On Thursday, we practiced and decided what we were going to do in the Domino Lab. At the start of class, we experimented with the photogates and tried to guess what they are used for. It turns out that they are used to time something. As a class, we decided that the distance between dominoes determines the speed of falling dominoes. We also came to the conclusion that we needed to measure the spacing between the dominoes, the distance for the entire rally, and the time it took for the rally to complete. The class agreed the speed equals distance divided by time. We then practiced setting up the dominoes at different distances apart and testing how long it would take to pass through both gates of the photogate. In order, to do this the photogate needed to be on pulse.