 The title of this lab is Density of Pennies. We are going to measure the density of the pre-1982 pennies and compare it to the post-1983 pennies. The lab is also about recording measurements with the correct significant digits and propagating those significant digits correctly through the calculations that you will have to do afterwards. You will also gain practice with the software that should be installed on your laptop which is called the Logger Pro. We're going to measure groups of pre-1982 pennies. The groups are formed by putting five pennies together and it's really important that you keep track of the weight of each group separately and in order to weigh the groups we first will have to zero the scale and that is the first group. Notice that the last digit will vary a little bit and that's because there is air flowing in the room and this is the total weight of the two groups. I've added the second group now. Now I will add the third group, the fourth group, and here's the weight of the fifth group. Okay, so now we're going to measure the volume displaced by each group of pennies. I have filled here a 50 milliliter graduated cylinder with about 20 ml of water or about 21 I should say and I will now add the first group of five pennies. You have to be careful when you add the pennies that the water does not splash out of the graduated cylinder. Please take that measurement and now I will add the second group, the third group, the fourth group, and the fifth group. Now that you have recorded this volume the next step is just to simply of the water and pull out the pennies and set them out to dry before we store them. Otherwise there will be a tendency for the pennies to oxidize and develop a coating which actually adds to the weight of the penny and provide us with an incorrect reading for their weight. Alright, so now we proceed to the next group of pennies, the post-1983 pennies. I will carry out the same measurements that we've done with the first group. The scale is zeroed so here's the first group of pennies and the second group and third group and fourth group. But wait a minute there is one of them looks a little bit different from the others and that is because all metals react with oxygen in the air. Okay, so what I'm going to do now is wipe the penny that has this dark coating on it which still will so that I remove this coating. The question to you would be why does this make a difference? Why would the oxide coating make any difference? So as you can see now it's clean as the others so we can proceed with our measurement. Okay, now I'm going to pick up the five pennies and form the fourth group. I'll go get the remaining five pennies. Form the last group, the fifth group. Okay, so I have here about 20 mils of water and I'm going to add each group of pennies that we have weighed starting with group one to this volume of water. Our job is to measure the volume increase that is caused by the addition of each group of pennies. That's group one and now it's group two, group three, group four. Now we're complete with the experimental part. Now is to go to Logger Pro, input the data and derive the density of the pennies pre-82 and post-83. Turn in a report when you're done.