Significant Zeros and Histograms

       This week’s lessons have varied a little bit, content wise but I have definitely learned in the process. For the first couple of days, we continued on about the prior week’s review lesson. In doing so we recorded each table groups overall information through histogram graph. I found this way of collecting data interesting because I have never heard of it before. Basically, you make a box from one number to the next to show what a certain group got. If more than one group got the same number, you would put another box on top of the original one. To be more specific here is a photo. I think learning about histograms and how to use them will be very helpful for me in the future. 

      Pertaining to the main ideas of this week of Significant Zeros and Significant Digits in measurement, I definitely feel that the lecture really did educate me on knowing what sig figs (significant figures) are and how they are used. Significant figures are digits that are counted as significant. For example, the number 9.627, there are 4 sig figs. With learning sig figs, also comes learning about zeros. I learned that there are many types of zeros. There are zeros that are place holders, which come after a digit or exact number (e.g. 100, 140, 80, etc.). There are also zeros that come before a number, when dealing with a decimal (e.g. 0.02, 0.016, etc.), these are Significant Zeros. Following this idea, we learned that once a measurement is recorded, all obvious numbers are recorded and one estimated number, this is known as a Sig. Digit. Here is a picture to be clearer about the idea. Significant digits in measurement overall have 5 rules. 1. All non-zeros are significant e.g. 9, 12, 35643) 2. Sandwiched zeros (those that occur between two significant digits) are significant (e.g. 1.005 having 4 sig. Zeros, 34.01026 having 7 sig figs, etc.). 3. Zeros that are only place holders for a decimal are not significant (e.g. 0.005 having 1 sig fig, 0.0047 having only 2 sig figs, etc.). 4. Zeros at the end if a number that also contains a decimal are significant. These "trailing zeros" are only significant if the number contains a decimal point, for example: 4.500 has 4 sig figs and 3.0 has 2 sig figs. Lastly, rule 5. This rule is for exact numbers (without doubt or uncertainty, like 173). Here is a chart for a better understanding. When dealing with digits, I also came to an understanding that one digit can also have more than one rule. For example, the number 6040. This number is significant because it fits into the guidelines of rules 1, 2, 3 and 5. This number has zeros, there is an "in between-er" zero between 6 and 4, this is an exact number with no decimals or uncertainty.

       In order to grasp these various concepts, our class worked with their assigned group members to work through 2 pogils. One pogils worksheet was about significant zeros and measurement, and the other pogil was about Significant Zeros. We also listened to an informing lecture and had a class discussion and these main ideas.

       Overall I think I have understood the concept of sig figs, but I feel I do need more practice to fully be able to confidently give answers to questions about them. As far as my participation towards the subject goes, I feel that I have asked questions that have I needed answered and that has helped me. My overall understanding of the topic would be 8 out of 10. I'm definitely looking forward to exploring more on the topic and other lessons that are to come.

Week Review 9-8/9-17

      Throughout the course of this past week we as a class conducted various projects. The main ideas for this week have been making predictions of how things work and also how mass is effected, through different experiments. These two main ideas connect by allowing us, the students to predict and learn how different elements and reactions affect the mass of objects.  I believe some of the important details to the idea of mass specifally, is the chemical aspect of these experiments.  When we were dealing with mass, there were definitely chemical reactions and elements that played into affect. We conducted 6 exeriments, testing how mass can be effected.
       For our first experiment, my group and I ran "Mass of dissolved sugar". In this lab we had to test the mass of water with a sugar cube inside vs. the mass of water with a dissolved sugar cube. It was hypothesized that the sugar cube would dissolve completely into the water and the mass would remain the mass. After conducting the lab, we learned that our prediction was incorrect. We observed the sugar cube slowly dissolving into the water and watched air bubbles rise to the top. Once the cube was dissolved, we noticed that is didn't necessarily dissolve completely but partially. There was sugar particles floating at the bottom of the vile. Overall, the resulted mass after this procedure has decreased by .4 grams.
       The next experiment we did was the "Mass of percipitate"lab. For this lab we weighed the mass of CaCl2 (Calcium chloride) and Na2CO3 (Sodium Carbinate), both in separate viles, this total mass resulted in 53.4 grams. Before combining the two chemicals in one vile and weighing the mass, we hypothesized the the mass will neither increase nor decrease. After weighing, the resulted mass in 53.3 grams. I believe this .1 decrease was actually due to human error, while using the electric mass scale.
       Following the previous experiment, my group and I performed the "Mass of Steel Wool" investigation. We took steel wool and weighed the mass, before and after tearing it apart. We envisioned the piece of wool to have the same mass, being that we only changed the form of the wool. I think there was another human error that effected our results. Pieces of the material was continually falling off as we separated the wool. The pieces weren't landing in the tin pan under the wool as planned, but on the table and floor. Due to this happening, the resulted mass had decreased by .3 grams. This particular test follows into our next lab.
       Using the same steel wool from our previous lab, we performed our fourth lab which was "Mass of Burning Steel Wool".  With the same piece of wool we burned it and took observations. As we burned it we noticed particles were falling off of the material. Due to this observation, we predicted the matter would decrease in mass. Shockingly, our prediction was wrong. The piece of wool had increased .6 grams (from 20.7g to 21.3g). Throughout all of these tests, I found it interesting how these changes of mass came about. We continued onto 2 more experiments to examine how mass can be effected.
        For our fifth test of examining how mass can be effected, we conducted the "Mass of Ice and Water" investigation.  For the test, we weighed the mass of a piece of ice in a vile. After doing so, we melted the piece of ice by holding the vile with our hands, transferring our body heat. Our groups hypothesis for the resulted mass was that the mass would remain the same. We were only changing the matter from solid to liquid. As expected, the concluding mass came to be 10.7 grams, which was also the same mass of the ice.
       The last and final experiment we conducted was the "Mass of dissolved Alka-Seltzer" investigation. Like the sugar cube investigation, we tested the mass of the alka-seltzer in a vile with water before and after it was dissolved. It was predicted that the mass would stay the same. It was interesting to observe that there were bubbles rising to the top, just like with the sugar cubes. Like the sugar cube test, the Alia-seltzer had also decreased in mass, going from 34.98g to 34.84. I definitely think the air bubbles might've had something to do with the reasoning of why the mass had decreased.
       Through these various experiments, I feel that we were able to learn the main ideas by observing and testing how mass of an object/liquid can be affected and recording the data. We were also able to weigh the mass of there various test subjects by learning how to use an electric scale and non-electric scale. Overall, I don't feel as though I have any follow up questions about these main ideas of this week. I enjoyed experimenting and observing the different affects due to these ideas. As far as my participation goes for this weeks learning process, I feel that I was quite active. When doing journal boards with our table I almost felt like the leader in a sense, which doesn't happen often but I enjoyed. I made sure to ask questions in order to fully understand the material. From 1-10, my understanding of all of the ideas for this week would a 10. My ideas about the main topics of this week I don't feel have changed because I already knew information about mass from previous classes but it was definitely a refresher for me. I look forward to continuing on with new experiments and new ideas to investigate.