Wednesday, February 22, 2017

My Favorite Task Essay
my favorite task that I have done in this term is the ice cream lab. because ice cream lab is not just the lab that we do it seriously, and also we doesn't get only the science skill in the lab for this lab we also get the opportunity to learn how to choose the ingredient not even just use our lab skill to this experiment also we get the cooking skill as well. I love cooking with science would be more fun I like to have lab like this more frequently. 

                          Leaf Test for Starch

Apparatus
  • 4 green leaves
  • Beaker
  • Bunsen Burner
  • Tripod
  • Test Tube
  • Ethanol
  • Iodine
  • Pipette
  • White paper


Procedure
  1. After 4 green leaves were collected, 2 of them were put into the beaker of 150 mL of water boiling over the bunsen burner and tripod.
  2. After 2 minutes, the leaves were taken out from the beaker and were put into the test tube of ethanol. The test tube was then put in the warm beaker used in step 1.
  3. After some time, the leaves were taken out from the ethanol test tube. They were then laid down on a white paper along with 2 other fresh leaves.
  4. Iodine was dropped onto each of the leaves on the paper using the pipette. The color change of the iodine drops on the leaves and the soaked iodine on the paper were then observed.


Photos



Observation
  • The color of the iodine on all 4 leaves were too dark to be observed.
  • The paper soaked by iodine of the fresh leaves were colored orange — the original color of iodine. This means that the result of iodine test on the fresh leaves was negative.
  • The paper soaked by iodine of the boiled leaves were colored dark-purple. This means that the result of iodine test on the boiled leaves was positive.


Discussion Questions
  1. Why do we boil the leaves? - When the leaves are boiled, the cell walls are weakened and broken, allowing the organelles including the chloroplast out, stopping all the reactions from taking place inside the leaves.
  2. What is the leaf texture like after boiling? - The leaf becomes softer, smoother, and appear less green.
  3. Why do we use ethanol on the lead after boiling? - We use ethanol on the leaf to extract the chlorophyll out.
  4. What is the color of the water after boiling the leaf? Why? Why did some people get pink brown water? - The color of the water appeared pink brown after boiling because the leaves are relatively small and thin relative to the leaves of other groups. The boiling time is therefore too long for the leaves and substances other than chlorophyll are extracted as well.
  5. When you test for starch with the iodine, why did the paper turn black? - After the iodine is dropped onto the boiled leaves, the iodine turned black because the starch test is positive. When the iodine soaks the white paper, it then turned the paper black.
  6. What happened to the iodine test on the unboiled leaf? Why? - The iodine didn't turn black for the unboiled leaves because the chlorophyll and the starch is not extracted out of the cell.

TITRATION

Apparatus

  • Strong Acid (HCl) + Phenolphthalein
  • Weak Acid (HCl) + Phenolphthalein
  • Base (NaOH)
  • Stand
  • Clamp
  • Burette
  • Beaker
  • Filter Funnel
Procedure
  1.  The Burette is clamped onto the stand. Then, the base is poured until it reaches 50mL mark of the burette.
  2. A beaker filled with 10mL of acid is set up under the Burette stand.
  3. Carefully and patiently, the base is released from the burette. Every time the base is released and the indicator turns purple, the beaker is swirled. Until the acid permanently turns purple, more drops of the base are added to the acid.
  4. Once the acid does not turn clear again even after swirling, the volume of added base was identitied by looking at the scale on the Burette.

Photos


Questions
  1. What is the molarity of the HCl? - 0.365M
  2. What is the molarity of COOH — acetic acid? - 1.285M
  3. What are sources of errors in the experiment? - Because the change is very critical, a single drop can make the difference. The result can be inaccurate if multiple drops of base is released at a time and the acid does not revert back
  4. Conclusion: Titration can be used to calculate the concentration of an unknown acid/base solution based on another solution of opposite pH with known concentration. However, the result can be inaccurate if you are not very careful and patient in the process.

Wednesday, January 18, 2017

Essay

The GM plants can have many benefits for Thailand especially for agriculture. However, Thailand still not ready to be able to afford this technology in society. First, the GM plants need to be carefully tested before selling into the market if the products weren’t tested carefully by the producer. The consequence of this action can be created massive problems for Thailand crops and the consumers.Next, GM plants contain antibiotics, which will weaken the effectiveness of antibiotics used in your body when actually needed. Finally, it is impossible to prevent contamination of GM pollen into natural crops, meaning that GMOs will also alter the genes of natural plants instead of only within the GM plants. These make it wiser for Thai government to not allow GMOs given the current stage of the technology.

Objective: To learn about grafting plants.

Group: Guy, Shaq, Ohm, Richy, Gun


Hypothesis: If the cut maintains the connection, then the petiole should join with the node.

Apparatus
  • Plant
  • Scalpel
  • Lab Scissors
  • Clay
  • String

Procedure
  1. The chosen scalpel is cut in V-shape at the node.
  2. The leaf of the same species is cut in V-shape at the petiole.
  3. The cut of the leaf is held onto the node so that the gap is in an interlocking position.
  4. The graft gap is sealed by clay and tied over with string.
  5. The graft is left for 4 days before it is observed again.

Question

  • Why do we use clay? 
    • Because clay can be used to seal the grafting gap, also it helps to hold the interlocking section and able to let air, water and nutrients from the node reach to petiole.
  • Why do we cut at the node? What is the node? 
    •  Node is the part of the plant where branches can grow out. We cut the node because the vascular bundle can sustain the grafted branch. 
  •  Why do we use string to tie it?
    • Because the clay will break be viscous overtime which we need rope to continue to hold the clay together.

Observation

  • After 4 days, the grafted branch fell off to the ground along with string are untied and clay still holding the branch
  • The grafted branch can be fell down on the rainy days
  • The branch still alive after being observe which we hypothesize that the clay was holding water from the rain and keeping the branch alive. 

Discussion

  • KK's grafted plant work because the interlocking position was in the right position and also clay manage to hold the branch to connect with each other. 
  • The experiment were design to compare the grafted plant with the interlocking position and one without it. The result should show that the grafted plant in interlocking position still alive. 
  • The three keys consist of:
    • The interlocking position 
    • The clay should be sealing correctly 
    • The string manage to hold the clay 

Thursday, November 17, 2016



















The water was used for measuring the heat energy because calories scale are measured as the energy heating of 1 gram of temperature of water up by 1 degree Celsius. Furthermore, thermometer would measure the temperature of flame instead of the energy. 

There is a small amount of heat absorbed by water due to the experiment was in the open system which heat energy was distributed to other medium such as air. The error percentage of this experiment can be decrease by using a closed system which most of heat energy can be absorbed in water.

Conclusion

In the experiment, we calculated the amount of calories and compare it to the amount given by the manufacturer. The number that we calculated was only 4% of the number given by the manufacturer. Due to the experiment was in open system which cause the large amount of heat energy to transfer away if we manage to change from open system to closed system in the future. The experiment would be more accurate and less percentage error than before.  













  • This is because the brain analyzes the length of the lines relative to their surrounding. In this case, the line segment AB is the shorter diagonal line of the larger parallelogram and the line segment BC is the longer diagonal line of the smaller parallelogram.