January 31, 2011 - Reviewing Matter HW (review for quiz)

When we first got to class, Mr. Finley announced that the quiz that he told us about on Friday will be postponed to Tuesday, February 1. Then, he checked the homework from Friday, and we went over it as a class. The homework was about reviewing matter.

It was about the speed of particles moving, and how particles relate to the different types of energy. For the first question, it was about someone trying to open a jar, and they ran it under hot water. To demonstarte what the particles would do in cold and hot water, Mr. Finley did a demonrtation. 4 people stood in a line, shoulder to shoulder, tightly (they represented particles) and they started to "vibrate". This showed how the speeds of particles change from fast to slow or slow to fast. It also demonstrated how the particles tend to expand from each other.

For another part of the question, we had to draw particle pictures. Below are the ones from class:

The next question related to thermal energy. You had to rub 2 pieces of paper together, and explain why the temperatues incresed. It rose because the particles on each sheet of paper bump into eachother. The internal energy/thermal energy was increasing, as someone said. Next, we had to make a bar chart. 1 sheet of paper was the system, so it was doing work. The bar chart that the class made together was:

**the heating symbol in a bar chart is: Q

The bar chart basically explains:

Intitial: The paper didn't have energy because there was no work/heating being done

Work/Q: The papers were rubbed together, so it created heat

Final: The end showed the same amount of energy that was there while the papers were rubbed together.

Next, we discussed why the temeperature cooled down after it was rubbed. Someone in the class said the energy was transferred to the air (the paper was heating the enviorment). Mr. Finley decided to relate it to real life. So he asked what what we mean when we say "heat". Somebody answered that we mean "hot air". So, this proved that by rubbing two things together, its not making you feel heat, it is really making hot air around the objects, so you feel that. After doing that, we learned how to draw a bar chart with negative thermal/internal energy. It would look like this:

Initial: Some thermal energy

Work/Q: Lose part of the existing thermal energy

Final: Only a little thermal energy left

Finley went back to energy transfers and compared school to it. He said that after school when he is working, and no one is here, it's colder. The energy isn't transferring because there are not any people moving around and causing a lot of energy.

The last part of the homework was the lemonade problem. It was a situation about cold lemonade in hot water. Finley wanted to know why the temperatures became the same. The difference of the hot water transferring energy and the energy steeling energy lead to the temperature change in the lemonade situation. It went from warm to cold which brought us to the 2nd Law of Thermodynamics. The 2nd law is getting an equal lybrium. In this 2nd law, energy always moves from warm to cold (high to low). The first law was the transferring of energy concept.

That was all that we did in class today, but we have homework. It will be posted on Mr. Finley's website. He told us that it is about finding 3 types of heat. Before we left he gave us 2 hints though:

***2 of them start with the letter C, and the other one starts with R.***

-A.L. (3rd)

In Class today we went to the Phet website. Then go to play with sims, Then go to states of matter. First he wanted to see what would happen if we put an icecube on a counter. We councluded that if you do the particles would start to heat up and vibrate faster. The next question was what would happen to the motion of the particles if it changed from solid to liquid. Also if it changed from liquid to gas. We said that the particles were vibrateing and spreading out.


-MM

MA 1-25

Today in class, on 1/25/11, we did many things.

First, we did a practice problem for density: a soup can, with radius=2cm, h=5cm, and the mass=300g. We had to find the density. In order to, Finley gave us a cool pneumonic device to help us rememebr formulas for circles and cylinders: for a circle, it's 3.14r(squared), and since a cylinder is really a bunch of circles on top of each other, you multiply that equation by the height, h. You get 3.14r(squared)h. The density was 4.78 grams per cm.3

We also went over the homework. It would be hard to put up all the answers here, but i'll put some of the conclusion questions:



2. An object with a density of 0.67 kg/L would float 2/3 underwater.

3. A floating object has an upward force that is equal to the downward weight.

4. What would happen to an ice cube if it was dropped into a glass of 100% ethanol (density= 0.789 kg/L)? Would it be pushed up more or less? Why do you think this?

It would be pushed up more and down less. It would be because, if you look at the data, you can find this rule: if the object is less dense than the liquid, it floats. Contrariwise, if it is denser than the liquid, it will sink more.

http://en.wikipedia.org/wiki/Density
that helped me understand some of it.
-MA
3rd

1-24-11 Density

Today in class we got back our test, and packets.
Notes:
The amount of particles is the mass.
Unit Rates:
In order to compare, the unit rate must be the same.
mass: 1 unit of volume

mass
---- = density
volume

You have to make the unit to 1, because it is easier to compare to the volume that way. The goal is to compare two masses.

Next we went online to phet. We are supposed to answer the questions posted on the website for homework.

To get to phet, you google phet. Then you click on play with sims, then density, then run now.

The website is below:
http://phet.colorado.edu/en/simulation/density"
In class, we began this while working with a partner.

We came up with the formula that density = 100* the %

KK this is my 3rd blog

January 21,2011-- Denisty

What is density?

-- Amount of particles or mass

-- To find the volume, you multiply length*width*height.
-- The size of the object doesn't change the density. Like materials will have the same amount of density even if one object is bigger than another for example, a life-size gold Jenna statue versus a a solid gold ring has the same density

Unit Rate example: x miles per hour (for every hour, your drive x miles)

To be able to compare, you have to "minimize" the volume down to one.

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This is a bit of the packet we worked on showing how to reduce a ratio.
21.6 g : 8 cm3

2.17 g : 1 cm3-------> 2.7 grams per centimeter cubed

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milliliters cubed is another way to measure volume

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Reflection: Because of the activity with the floating/sinking cubes, I now much better understand the concepts (mass, density, volume, etc..). The packet also helped me becasue I had to figure a out the mass using only the volume and density, for example.


This is an example of the website we worked on where all the cubes had the same amount of density.

JF 3rd

Wednesday's packet review (1-19-11)

Today (Wednesday) we had to finish our packet by the end of the period because it will be graded as a quiz. Last week we worked on all of 5.2 and 5.4 with the sub. Yesterday since it was a delayed opening and we just got back from the weekend, we weren't expected to finish the packet thus making it due today.

Overview of the packet:

5.1

examine a book on your group's table.

a. We thought the book (our book) resembled a rectangular prism

b. You can learn about it's length ( 25.5cm), width (20.5cm), surface area (522.75cm^2, 102cm^2, and 82cm^2), volume (2091cm^3), and depth/height (4cm).

c. Perimeter to SA is basically the distance around an object/shape to the unit per area inside the object/shape. Area to volume is basically the same thing but 2 dimensional to 3 dimensional.

d. the volume of the book is 2091cm^3 and we got it by the formula l * w * h = v.

e. yes, there is a formula to find the volume of a soda can (cylinder) by h * c * r^2 = v.

f. No, you can't use the same approach to find the volume of a water bottle because it is made up of multiple 3d shapes instead of one.

5.2

a. Volume to length is practically 3d to 1d because length only measures one line. V to A is, like I said earlier, 3d to 2d. we measure volume in cubic centimeters.

b. There is more than one way to measure the volume of the given object (ping pong ball, coin, a toy, and a dice). A few ways are to use an overflow bucket, use a formula with any variables needed, or a graduated cylinder.

c. Answers may vary

d. You can write down the result of each measurement by adding the uncertainty. Also, if it is compared together with two different units, then you can transform the units into one and then add the uncertainty.

e. answers may very

f. answers may very but your answers should either be the same or close enough to compare.

g. answers may very but uncertainty added to each result should make both the same or even closer.

5.3


It is important to have many ways to find the volume of an object to double check your results and to give you a better understanding of the experiment.

5.4 (if I get an answer wrong you can explain the correct answer below)

a. 0.016666 repeating hours are in a min. 60min = 1hr

b. 1L = 0.2642 gallons 3.785L + one gallon

c. 1,000g = 1kg 0.001 kg = 1 g

d. 1,000,000cm^3 = m^3 0.000001 m^3 = 1 cm^3

e. 1cm^3 = 1ml 1ml/^3 = 1cm

Sorry that I couldn't post this yesterday. Comment if you have anything to say or anything to add!

BB (3rd Blog)

Density- P2

Today in classs we reviewed and learned more about mass and particles. To start the class off, we were to look at this table:

Mostly evaporated-(volume) 1000cm^2 (mass) 100g

Open to air-(volume) 1000cm^2 (mass) 1000g

Pumped with air-(volume) 1000cm^2 (mass) 1100g

Throughout the graph, the volume stayed the same, but the mass increased.

To see a visual example, Mr. Finley placed a slightly inflated rubeer glove inside of a jar. He then asked "What will happen if we pump air out? After testing this experiment, we found out that the glove inflated with air and increased in mass.

Things to Remember: Dense- amount of particles in one place.

Mass- particles

SD