Category: Essentials

Problem:  Given a certain quantity of marshmallows, graham crackers, and chocolate pieces, what is the maximum number of S’mores that can be made?  Then figure out your percent yield!

Substance	Symbol
Graham Cracker (half of a cracker)	Gc
Marshmallow	M
Chocolate Piece (individual piece of chocolate)	Cp
S’more  (2 crackers, 3 pieces of chocolate, 1 marshmallow)	Gc2MCp3

Procedure/data:

1. Use the 3 different reactants and one product to write a balanced equation for the making of s’mores

2 Gc +    M + 3Cp →   Gc2MCp3   

2. What type of reaction would this be classified as?

Chemical and physical changes.

3. Record the total moles (pieces) of each reactant available at your table

Graham Cracker (Gc)-  6 Marshmallow (M)-  4       Chocolate Pieces (Cp)- 9

(amount of halfs of Gc) (each single marshmallow) (each single chocolate piece- 12 per bar)

4. What is the maximum number of s’mores that your group can make?  

Why? The maximum number of s’mores is 3 because graham cracker and chocolate pieces are the limiting reactant and only consist of a certain amount that is enough to make 3 s’mores.

Which reactant/s is/are limiting?  (the one/s that you will run out of first) : graham cracker, chocolate pieces

Which reactant/s is/are  in excess (the one/s that will be left over) : marshmallow

5. Find the mass of one of each of the individual reactants (first zero a napkin and then find the mass on top of the napkin)

Graham Cracker (Gc)- 8.17g Marshmallow (M) – 4g Chocolate Piece (Cp)- 3g

(one halfs of Gc)       (one single marshmallow)      (one single chocolate piece)

6. Record the theoretical yield/mass of a S’more (Gc2MCp3) using your reactants (you can add them together)

[(8.17*2) + (4) + (9)] = 29.34 g

7. Make your s’mores 

a. Make sure that you follow the chemical reaction equation and get all of the reactants ready.

b. roast your marshmallows over the Bunsen burner using a skewer. And then make your finished product.  

c. Before eating your s’more find the actual mass (yield) of your s’more

(put a napkin on the scale, zero the scale and THEN put on your smore).

The ACTUAL (experimental) mass of one s’mores: 29 g

8. Find the percent yield of your s’mores:.       Theoretical yield = from part 6 Actual or experimental yield= from part 7c

(29/29.34) * 100

percent yield=98.84%

Objective: To observe the relationship between various elements and their emission spectrum.

Introduction:

Flame tests provide a way to qualitatively test for the presence of specific elements by seeing colored flames.  The heat of the bunsen burner excites the electrons in the atom, and this energy is released as the electrons “fall back” to their ground states. The color we see is a combination of the visible wavelengths of light emitted by the atoms.  

If you have a spectroscope you can also make quantitative observations. A spectroscope can be used to see a pattern of narrow lights called an emission (bright-line) spectrum.  The actually wavelengths of the spectrum serve as a quantitative test to determine atoms identities.  Each element has a different “pattern” of electrons so it will show a different combination of colors.  

In this lab, you will perform flame tests on seven different elements. You will use your observations to identify an unknown solution.

Prelaboratory Questions: (In a section labeled PRELAB- answer the following questions in FULL sentences)

1. Why do we see colors in the flame tests?

The increase in temperature makes the electrons excited and move to a higher energy level. They produce visible light as they return back to the ground state.

1. How will we be testing the substances qualitatively?

One way could be comparing the color of flame (of each element) with the Bhor model.

Materials:

Safety goggles, wood splints, tongs/tweezers, Bunsen burner, test tubes with various compounds

Safety:

1. Safety goggles must be worn at all times
2. Many of these salts are toxic. If you come into contact with any of the compounds make sure to notify the teacher and wash the contacted area thoroughly. Wash your hands before leaving the lab!

Procedure:

1. Light the Bunsen burner (turn the gas on so you can just hear it, then use the striker)
2. Place the wood splint for each compound into the flame using tongs or tweezers- ONE AT A TIME!
3. Take note of the color of the flame and return the wood splint to the solution.
4. CLEAN UP YOUR STATION! Carefully put the stoppers back on the solutions! Make sure the station looks like it did when you started! Let me know if you need new splints!
5. Wash your hands thoroughly before leaving the laboratory

Data Table: make a section of your lab labeled Data Table and make a data table similar to the one below to record your observations.

Compound	The color of Flame (qualitative)	Wavelengths of light (in Å) (quantitative)
Barium Chloride	Yellow (light)	600 nm
Calcium Chloride	Orange	630 nm
Copper (II) Chloride	Green	550 nm
Lithium Chloride	Red	665 nm
Potassium Chloride	Pinkish-orange	647.5 nm
Strontium Chloride	Red	665 nm

Discussion and Analysis: (In a section labeled Discussion and Analysis answer the following questions in complete sentences)

1. How do your results from the flame test provide support for quantized energy levels? Explain your answer.

The heat made the atom’s element excited and move to a higher energy level. The atoms emitted photons of visible light while returning back to the ground state.

Conclusion: (answer in a complete paragraph and in complete sentences)

What are two possible sources of error for this lab? How would the errors affect your lab? What would you do differently next time to counteract these errors?

There were many barriers in this experiment: the inconsistency of how much element should be put onto the stick, how to make sure the flame is actually burning the element but not the stick. These sources of error can lead to the inaccuracy in color of the flame. If we were to redo this lab, we need to make sure that the same amount of element goes on the stick and that the flame is actually burning them. We should repeat each burning process at least three times for each element.

On Monday, April 2nd, 2018, my Physics class started working on a new project called “The Physics of Superheroes” where each of us is supposed to choose a superhero that we interested, in which we will be research on the physics behind their superpowers. By the end of this project, each of us required writing a one-to-two page of well enough explanation about the complicated physics behind the superhero’s powers along with a poster that will display the important information from the writing paper as a visual product.

I chose to work on Spider-man and I was focusing on one of his superpower which was webbing. We need to properly identify the superpowers and connect them to laws of physics that exist in the real world. We also need to show that we understand most of the physics that we bring up in our paper as well as identifying which superpower is realistic and which is not. And last, I need to put enough effort into my poster and make sure that it can display important information in a creative way.

This project is really difficult for me personally because the physics behind Spider-man power is a really complex physic for me. It took me a lot of time to understand a concept. I finish my paper writing in four days and I started working on my poster the day after. This is actually how my poster turns out.

I actually really like that this project allows us to choose the superhero that we want to research about. I had learned a lot of incredible facts from this research project and I was really happy to learn that some superpower that seems nonsense can actually happen in the real world which is really impressive because it shows that we humans are really amazing! Through doing this project, it always reminded me of a quote that says “Nothing is impossible, the word itself says I’m possible!” Please enjoy my writing that I attached here.

      

[Translated into English:]

 

During the sad 1975, the Khmer Rouge had used violence to evacuate people out of their houses as well as their beautiful city, Phnom Penh, and people never get to return since then. They closed all of the markets and schools. We also lost our culture. Some of the pagodas and schools have turned into a prison by the Khmer Rouge and had captured a lot of our innocent people. People don’t allow to have private ownership and instead, everything belongs to Angkar. Each person has the same amount of work. Everyone is farming and must wear black clothes. There weren’t any family relationship at that time. To follow their goal of making everyone equal, they started to kill the minorities like Cham, China, and Vietnam violently. After, they started to force people to work harder by telling them to produce 3 tons of rice per hectare without giving them enough nutrition to gain the strength to continue working. If people don’t follow what Angkar said, they will be killed.

[Information based on: http://www.cambodiatribunal.org/history/cambodian-history/khmer-rouge-history/]

Currently, we’re learning about the inclined plane as well as different type of friction: static and kinetic friction. Whenever we do word problems in class, the situation in each problem always have something like gravity always equal to 10 m/s^2 and object start at rest (Vi = 0) and etc, which doesn’t illustrate how our real-world work. In this inclined plane and friction section, we had done a lab to experimentally determine the coefficient of static friction for multiple materials, and understand that we had made a lot of assumptions in the problems we do on the board.

So basically we just place a different object upon the wood with the different sandpaper and find out the angle of the very first moment that the object starts to slide down. After that, we will collect the data and analysis it as well as answer some question like below.

Friction Lab

1. Sandpaper 4

2. Sandpaper 5

3. Sandpaper 2

4. Sandpaper 3

5. Sandpaper 1

6. Cloth

7. Wood

All the assumption we make in the problems we do on the board are:

1. Constant velocity

2. No friction force

3. Start from rest

4. Gravity is 10 m/s^2

5. Everything is flat

These are the real-life problems we faced in the experiment:

1. We always apply some little forces when we place the object upon the surface

2. The measuring is not accurate (using our eyes)

3. We didn’t do a great job in placing the sandpapers on the wood. The surface isn’t flat, which will create more friction

On November 1st, 2017, in the English Literacy class, we had a writing activity with Halloween theme. Basically, we’re getting a piece of paper where we can begin our story and the next person beside us will then continue the story. We’re repeating this process until we get our paper back. I begin my story with a creepy characters and spooky moments. But as the story continue, it becomes really silly because there’s always a person in the team to ruin the story. So I bold the part that I wrote throughout the story. So this is one of my favorite part from my short story, although it a bit silly. You can also click on the link here to read the whole story. In this case, writing is very fun!

“Then there was a ghost running toward me without legs. I wasn’t sure why and how but I had no time to ask her, so I ran back inside. But another ghost appeared in front of me and asked me a question. If I got it right, I can go in but if I don’t, I have to eat 25 broccoli! The ghost asked, “What is me?””

Currently, Math is one of my most favorite essential of all. But it’s also a bit complicated too. At the first 25 minutes of class, we would start by receiving a mini lesson from our math teacher. This is a time period where I’ll be staying focus as this time period will help me to influence in my learning for the last period of class. In Liger, my math class is somehow a bit different from a normal math class I have had. Beside having our teacher talking with his textbook and whiteboard all the time, we’re also using an internet resource as well, which called “Khan Academy.” Currently, I’m working on a course called “Transformations.” It’s an online course that had played an important role in influence my understanding about this lesson. Looking back to what I had done, I can see a huge progress I made in math. It took be a really short time to do this much work on this course. But, this lesson is still a bit confusing to me though. However, I will commit to myself to put in a lot more work in the sight of improving my ability on math. I strongly believe that by doing a lot of practice, I will soon become a stronger math student and get into the level where I’ll be prepared for the real SAT.

In my Khmer class essential this week, I had have a class time period to go through and observed the structure of each individual book. We kind of doing the observation independently, but it was really fun and I got to learn a lot things from this activity. I carefully looked deeply into each page of the book. At the end, I compare each structure of the book with the other classmates. The structure was really similar to each other, but there was also some part that were different as well. I was really excited to share what I got to my friends in class. After this mini-lesson, we returned back to learn about the research paper again.

Currently, we’re mainly focusing on writing section. In class, we’re divided in groups of 4-5 people to do a brief research on what really is a research paper. Everyone in my team had put in a lot of hard work in researching this, and because of us having a strong researching skill, we had been able to get this work done perfectly. In our group, we’re using internet & technology to find those relevant information. Last, we copied down all the work we’ve done into the paper in order to show it to everyone else in the classroom.