Signifcant Digits Practice

Over the last week our class has been learning about signifcant digits, and how they work and why we use them in science. I have to admit at first the idea was foreign to me, and we spent a lot of time practicing them in class, but I still made mistakes every once in a while, and was getting frustrated. We have a test on Tuesday, and I was worried that I wasn't prepared enough so I looked up a website that might be able to explain them in a way the book was unable to. Luckily I found one that did just that. I found that the textbook only provided practice problems, they didn't ever provide a step by step example, but this website that I have linked below really helped me, and can help anyone who is struggling with the concept of significant digits.


www.physics.ca

Mole Project

Over the last 2 weeks I have been working on a project that might sound strange to some people, but it was actually quite fun! First, let me provide some background knowledge, as you might know there is a type of scientific measurement called the mole. The mole is a unit used when dealing with atoms and molecules, one mole is 6.02 x 10^23, a mole is one of the most used units in chemistry despite only being used when dealing with things at a molecular level. As for the project, our class, including me, all created moles, but not scientific moles, actual moles! like ones that live in the ground, we made them using fabric and fiber fill. The class wanted to be creative, so we all gave each mole a different theme, mine was a MOLEgician. The project overall was a load of fun despite the amount of times I poked myself with the needle while I was sewing the fabric. I assume the project was originally assigned to express the importance of the mole to us, and I believe that it worked because as soon as I was done making my mole I looked up the origin and use of the mole and why it is important, and I agree, it is very important. Here is a site that helps with conveersions using moles:
Chemwiki, and here is a link that etaches about the history of the mole: kentchemistry.



This was my Molegician.

Star Log

Earlier this week I completed a log of constellations/solar bodies, it's called "The Elements In The Stars." The project included me collecting data on 15 different solar bodies; although this may sound borin, it was actually quite enjoyable, and I actually learned some things I didn't know about before. For each star I told its classification, name, location, visible spectrum, and provided a picture. I don't know about you guys, but I've heard references to certain stars in things like conversations, books, and movies, but I never knew what they were talking about. Now that I have a star log not only have I gathered new information on the topic, but I have a place to refresh my memory.

Aspirin Lab

Earlier this week I was observing several other groups doing a lab. The lab was creating aspirin, it involved the use of a couple of dangerous chemicals. They were using sulfuric acid and acetic anhydride which are both highly toxic. I would ahve participated, but my lab partner forgot to study the lab and failed to answer some of the pre lab questions, which meant he was unfit to continue on with the experiment. However there were 5 other groups that were able too, and that is important because we will be using the product from the experiments for several others to come. The lab itself isn't very difficult. it is just very important that you know what you are doing so you do not hurt yourself. The lab procedure is as follows:

You might have noticed that there is part of the lab that I left out, that is because the portion of the lab was on how to purify the aspirin which wasn't nessecary for our experiments. The reason we did this lab meant little to our current unit, but as I said before we are using the product for other experiments that we will be doing next unit.

Atomic Structure and Radioactivity Unit Test

Today I took a unit test in chemistry, it was over atomic structure and radioactivity. I felt that most of the test was fairly easy, but I was a little stumped on the few questions regarding positrons. I guess that I had not studied them well enough, or I might have just gone brain dead, but I completely forgot what they were, so when I got home I looked them up online and found a few helpful sites.
Britannica, Chemteam, stlcc.

I also found it hard to remember how to find the percent abundance of the lighter of 2 masses given. I rem ember learning the formula in class, but I could not recall it during the test. Luckily I understood the concept well enough that I was able to determine the answer without using the formula. Since it gave the total mass of each isotope and the average atomic mass, I was able to determine depending on where the average lay between the 2 total masses, about what the percentage was, and since it was multiple choice, I was able to plug in my 2 guesses to find out which one matched the average.

Half Live Lab

Yesterday, my lab partner and I finished calculating and inputting data into excel. The data I'm talking about is the data we recieved from the experiment we did 2 or 3 days ago. The expreiment was quite simple, we cut pieces of paper into 567 pieces, I will explain why later, and we pretended that the 567 pieces of paper was a sample of a radioactive element. the way this works is the paper is colored on one side and isnt on the other, after you cut the paper you  put it into a cup and then pour them all out. At this point some of the paper should be color side up, and the other should just be plain white. Once you have poured out the pieces you serperate them ad choose either the colored or non-colored pieces of paper to be the decayed portion of the element, and the non-decayed portion. The idea is that you are simulating a half live by doing this since you should have close to 50% of the pieces to have decayed and 50% to have not. Of course in real life it will always be exactly 50% decayed if the element underwent a half live. After you serpearate them, you take the "non-decayed" portion, and you do the same thing, but with only those. You repeat that about 6 times the ncollect data on how many were left each time. Now for the reason we did this, not only did it help us understand the idea of half lives, but once we graphed our data it visually represented what the graph of a half live looked like.

This is what the the paper looked like inside the cup

(half of it was birthday decorated, the other half was plain).

This paper had a scenario that we had to figure out, we had to figure out who the victim was

by using halve lives and the information given. Although the data we collected was not mandatory in figuring out who the victim was, it helps alot to have it visualized in your head what halve lives look like.

Here is are some links to websites that can help you with half lives if you need it. Chemteam,

Wikihow, GCSEscience.