Thursday 9/30/10

part one of the lab
part two of the lab

data collected from lab completed in class

Today in class, we were given six sheets, two for the lab we did in class, the other four we didn't get to yet.

The lab todaywas the Rutherford Simulation Lab, in the lab we took a piece af paper with six circles on it, and six small squares at the center of each circle. We layed a piece of carbon paper on top, and with a partner, bounced a marble on top of the paper 110-120 times. After we finished, we counted the number of dots: in the circles, in the squares, and out side of the circles.

Using the collected information we found various data, like the percentage of dots that landed in the circles, for example me and my partner got 69 dots in the circle, out of 120 dots. to get the percent divide the number dots in the circle to the number of total dots: 69/120=.575 or 57.5%.

then using the total area of the paper, 93.5in. sq., and the percent of dots that landed in the circle, we found an estimated area of all 6 circles. We did this by multiplying the area of the paper times the percentage in decimal form: 93.5*.575=53.76in. sq.

Using the information we just found, we divided by six to find the next question, which was, what is the area of one circle: 53.76/6=8.96in. sq.

Then we solved to find the radius. To do this divide bothe sides by pi, then the square of your answer. To solve for diameter, multiply the answer you just got by 2. 8.96/3.14159=2.85 then the square of 2.85= 1.689in is your radius. 1.689*2= 3.378in is your diameter.

For problem 7, use a similar process to find the area of a square, like finding the area of a circle. First divide the number of dots in the squares by 120, i got 2/120=1.56, then divided by 6 to get one squarer alone. 1.56/6=.259in. sq.

to find the length of a side, take the square root of the area of one square.

Question Answers:


What does the paper represent?

the gold foil

What does the circle represent?

the atom

What does the marble represent?

the alpha-particle

What does the square represent?

the nucleus of the atom

The true diameter of each circle is 3.2 inches. find your percent error. to do this subtract your value minus the true value, then divide by the true value, and multiply by 100.

>>> (3.378)-(3.2)=.178/3.2=.055625*100=5.5625%

What could account for your own error in this lab?

>>>answers may differ. ex: not enough data collected.

Homework: Finish Question Four of the Lab, Test next Friday, October 8th, 2010

Next Scriber: Lauren

Wednesday 9/29/10

Modern View-electrons can be in ground or excited states and can jump between levels. When electrons drop levels (high to low) they give of a beam of light! Its like bees in a beehive and bees are electrons moving around the nucleus like a cloud. Similar to the picture above

Niel Bohr from 1914 discovered that electons(-charge) "ORBIT" around positive nucleus in different- ORBITALS(levels). Electrons can jump up and down these levels. As seen above.

Rutherford discovered all atoms have tiny positive centers(nucleus).

Ernest Rutherford from the early 1900's shot alpha particles(+ charge) through gold foil as shown in the picture above. Most of them went through but some deflected and these some were - charged particles!

Joseph John Thomson or J.J. from 1897 studied cathode ray tubes. He would excite the gas in the tubes with electricity. He would hold a magnet to the sides of the tube noticing a bend in the light (+ side attracted beam, - side repelled beam). He discovered that atoms must have a negative(-) charge and if that, then with overall neutrality, they must also have a positive(+) charge. This is demonstrated in his model above.John Dalton was an english schoolteacher from the early 1800's. He thought that each element was mad of elements, an atom of one element would be identicle to an atom of the same element. Also atoms do not include the existence of the nucleus, dosen't explain the existence of ions or isotopes, and dose not talk about subatomic particles (electrons, protons, and neutrons). His view of the atom looked something like the picture above.

Today we started off class by finishing the notes from yesterday on the Atomic scientists (Dalton, Rutherford, Thomson, and Bohr). You may look at yesterdays scribe for what they look like and foe more help.

After that Mr. Paek gave a lecture on the four scientists, their major contributions, what they discovered about the atom, and their actomic model. As shown above^ NOTE: start from the bottom picture and read up!!

no homework! lab test due by next friday!

Next Scriber: Maddy M.

Tuesday 9/28/10

Black container that contained the bead. There were 12 different containers with differents line patterns inside of them.
(scroll down all the way for more details)

Black box lab

We did this sheet in class. The sheet had four atom scientists' names and we had to fill out information about them. The information can be found on the colored sheets pictured below.

These are the colored sheets of paper with the information on  four atomic scientists. (Dalton, Rutherford, Thomson, Bohr)

2nd part of the black box lab

Today in class, we started a new unit. We began studying the atomic theory. We did the Black Box Lab. In this lab, we had to go to several stations with black circular containers. Each container had a bead inside of it. We would rattle and move the container to determine what type of shapes/lines were inside of the canister. We could determine the shapes by feeling how the bead bounced off the surfaces, and how the bead sounded when it bounced off certain spots of the container. We weren't allowed to open up the container to see the shapes.Then, we would sketch what we guessed was in the container, on our lab sheet. It was sort of like the concept of trying to figure out what atoms looked like, back in the days of Dalton, Rutherford, Thomson and Bohr, who were atomic scientists.

We got four colored pieces of paper with information about 4 different atomic scientists. The information on the sheets of paper can be used to fill out the Atomic Scientists worksheet that we got to do in class.

Next Scriber: Grace Ridge

No homework. Test next Friday, October 8th, 2010

9.27.10

Today in class we did not do anything complicated. It was an easy day and we reviewed the test that we took last Thursday. We also talked about the lab test that we took last Wednesday.

First of all, we started off by getting our journals back from Mr. Paek. He was supposed to check them in for points, but he did not yet because he was a bit too busy. To get an A for the journals just make sure the pages don't fall out and that they should be in a similar order to Mr. Paek's journal. We also got four new pages for our journal for unit two. (The new pages are shown at the bottom.) Please leave a blank page after the first two pages to have a page titled, "Text Questions." He also crossed out the names of people who were scribers, so if you were a scriber already, make sure you tell Mr. Paek.
Afterwards, Mr. Paek said that there were good news and bad news. The bad news was that the class did not do a good job on the lab test. Since our class did poorly, he is giving us an opportunity to get half the points back from the lab. In order to get the points back you can go see Mr. Paek during 5th period, 6th period, before school, or after school to work on a worksheet based on the lab test. You have one week to get points back from the lab test, so the option to do the lab worksheet is open until next Monday October 4th. The good news is that the test results were great! We got back our tests today and went over a few problems. After getting back our test, we also got a grade report. As a reminder, remember that labs/projects are worth 20% and tests/quizzes are worth 50% of your chemistry grade.

--The four new pages:

This is all what we did during class today. If you have any questions make sure to ask Mr. Paek. Also, don't forget to get the four new journal pages! There is no homework tonight!

-Next scriber: Alyssa P.
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Friday September 17, 2010

Today in chem we did a lab titled "Matter Lab Stations", learned about diatomic molecules, and completed a chapter 1&2 review sheet. For the lab, all of the tables had models of molecules and atoms made of different colored balls (pictured below). We went around all 6 tables, and completed a sheet that required us to draw a picture, write a formula, and list all the terms that applied.

The terms we used were;
Atom, Molecule, Pure substance, Mixture, Compound, and element.

We were told that;

yellow-Hydrogen

black-Carbon

red-we could choose any element, but the majority of the class chose Oxygen.

When we finished Mr. Paek went over it with the whole class.

Diatomic Molecules
After we went over the lab Mr. Paek told us about Diatomic Molecules. The definition we got was: these elements will always be paired when by itself. In other words, when you see one of these elements it will always have a subscript of 2 when it is by itself, i.e. cannot be just one atom, it must be a molecule.

The diatomic molecules are

H-hydrogen

O-oxygen

N-nitrogen

Cl-chlorine

Br-bromine

I-iodine

F-fluorine

Another way to remember these is by combining them to make a word 'honclbrif' pronounced hohn-cul-brif.

Review
The review sheet included:

density

conversion factors

molecules, atoms, compounds, elements

chemical and physical changes

states of matter

metric estimations

All of these will be included on the quiz on Monday, and the test on Thursday. There is a lab quiz on Wednesday also. Dont forget: the web assigns are due on Monday!

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