Summary

Summary

Since there're 20 odd posts, not all of which are in chronological order, to slog through, I thought it'll be good to include a guide. Do however note that it is a suggestion and some entries (e.g. trivia and hard copy) are better understood as the last.

No.	Lab Book	Personal Journal
1.	Introduction	Introduction
2.	Methodology- parts 1, 2 and 3	Hard Copy Journal
3.	Trial 1 Steps	Trial 1 Commentary
4.	Trial 1 Results	-
5.	Trial 2 Steps	Trial 2 Commentary
6.	Trial 2 Results	-
7.	Trial 3 Steps	Trial 3 Commentary
8.	Trial 3 Results	-
9.	-	Failed Experiment Commentary
10.	Experiment Steps	Experiment Commentary
11.	Experiment Results	-
12.	Soft copy; Rubrics	Trivia/Misc

22/10/2012 Addendum: Now that the report has been marked, Ms Tan requested that we put the soft copy online too, and the yellow highlights are her comments that I typed in. I thought it'd be more meaningful with the rubrics to give evaluations so that's on too. Soft; Rubrics.

Hard copy Journal

Hard copy Journal

Yeah...Since the concept of online journals was new to me, and I wanted to work in school but didn't have a laptop, well most of my initial brainstorming and lists of variables and whatnot are on paper. Very messy paper. So, here (clicking will enlarge the scans):

This is the preliminary brainstorming, when I haven't even settled what to cook. It started with dumplings (which then led to questions about consistency and factors involved), but then Ms Tan suggested fish balls...The format of my results were xy graphs pretty much from the start though, and this was also when the infamous Image-J debuted.

Variables/constants/likely relationships between them hashed out during science block, note the top with hastily scrawled ideas from discussing with others.

The difference between a theoretical experiment (and tables) with square tangyuan (in pencil) dreamt up during class and the actual trial with round tangyuan (in pen) developed after actually trying it. Who knows, there is a reason why generations of Asian women make balls instead of blocks. Also, see how the measurements ended up being halfway across the page because there wasn't enough space.

Cleaned up version of the table, still with random bits of data everywhere they're not supposed to be of course, plus reflections for the trials below.

Number crunching time after trials 1 and 2. The top part is feedback from friends who took a look at my blog so far, bottom is the data for density used while discussing the results with Ms Tan.

Working for the new shape of tangyuan (same surface area, different volume), and finally getting it.

Trial 0 and the actual experiment...

(p.s. If you're wondering why there're strange bulges all over the paper, why yes, I did spill water on it while cooking tangyuan.)

LB: Assumptions

LB: Assumptions

As per usual, there are assumptions made in this project.

1. Density of GRB is constant inside each GRB.
2.  Distribution of heat in water is even and the same amount of heat energy is conducted by the water in every experiment.
3. Movement of GRB within pot as they cook will not affect how fast they cook.*see above.
4. Cling wrap/plastic bags used in shaping the GRB/measuring them is insignificant to the results.
5. Impurities in Singaporean tap water ""
6. Cornflour used to dust the GRB "".

Director's Cut: Final E

Director's Cut: Final E

This will be in two parts, specifically pertaining to the experiment and as a whole after this project, because I am lazy and also it makes no sense to spilt reflections that are very much connected. 

1. Experiment

• The very fact that I acquired the use of the weighing scale by literally asking everyone I have ever met, then trucking my stove (and pot...and plates, measuring cylinders...flour...) to their house on the top floor shows that yes, how surprising, persistence is necessary. She was a very nice scale owner.
• I am the kind of person who would download a whole new set of software, in which spreadsheets were merely a part, just because I found those tutorials easier. But that's good, I think OpenOffice can produce better graphs than Excel, even though I've only used them significantly in this project. Developing your own taste and all that.

2. As a whole 

First time using:

• Image-J
• Excel/OpenOffice
• Online Journals
• Sniping tool on desktop (like screen shot, but more controllable)

I guess it's past time to start...Yeah, I can see spreadsheets being very useful in the future.


The method for using water displacement (and the equipment), the concept of density, etc was learnt in physics class, and Google was very helpful in covering the rest.

Part of my bookmark bar...

Trivia/Misc.

Trivia/Misc. 

1. While researching the properties of glutinous rice, I found an article on China's walls. Modern chemical analysis (by western scientists) revealed that they contained glutinous rice dough, whose stickiness was used in ancient times to reinforce the walls. It's really neat that I could link it to vague memories of reading chinese folktales about nian gao (also made of glutinous rice) being used as bricks. Reaching through the generations.:)
2. In the same vein, I didn't realized that much of Laotian rice was glutinous and it was their primary meal. Learnt a lot of esoteric facts from this project.
3. Photos/Video

These are the rest of the photos/videos that I took but aren't incredibly relevant/fit anywhere in the primary posts.

• My thumb drive

• Mixing the dough

Before:

Pot, chopstick and dough flakes

During: 

After: 

Finished dough

LB: Final Experiment Results

LB: Final Experiment Results

Date: 11 July 2012

Time: 4pm-7pm

Room temperature: 27°C

Weather: Sunny

For this final experiment, instead of slowly measuring each GRB's volume, I only measured 2 GRB and extrapolated the volume of other GRB from their mass, Also, instead of first setting the mass of a GRB, shaping it then calculating its surface area, I set the shape (volume and surface area) then recorded the mass to save time. 

Figure 1 shows that the density of almost all GRB decreased, possibly until lower than the water's density, hence floating. The time taken to float was proportional to an increase in size and the percentage change in density usually inversely so.

From figure 2, the variable with the strongest correlation to both time taken and change in density was surface area before cooking. It has a strong (near 1) positive correlation with time, making it very likely that if surface area is increased, time taken can be found to have increased proportionally.

Figure 3 is a graphical representation of the correlation factors, with a majority of points near the trend line in graphs representing variables with high correlation, figures 3.1 (correl:0.92) and 3.2 (correl:0.89), but not so in figure 3.3, with weakly correlating variables (correl:0.23). However, points in figure 3.2 are still further away than points in figure 3.1.


In conclusion, my hypothesis was that the higher the surface area to volume ratio of the GRB, the faster it would float, with the assumption that the process of cooking cause GRB to expand. This expansion decreased the density of GRB to lower than water, and a higher SA:V results in a faster rate of heat absorption by the GRB. Hence, the process of cooking is also faster, and the properties of cooked GRB, including expansion, would be exhibited faster as well.


My results do demonstrate a general decrease in density as well as an inverse relationship between surface area to volume ratio and time to floating, however, the relationship between surface area alone to floating time is actually stronger.


Edit 25/7: The completed report is now uploaded. 

LB: Final Experiment Procedure

LB: Final Experiment Procedure

Research Question: Does the process of gelatinisation cause the GBR to float?
Hypothesis: The higher the surface area to volume ratio, the faster the GBR floats in water.

Steps

1. Measure out 175g each of rice flour and water using a weighing scale, and mix until evenly distributed.

2. Take a small part and mix in green food colouring. Using the method outlined in this post, make a flat of 1 cm thickness.

I counted playing cards to make blocks of the correct height.

3.  Repeat step 2 4 times for 4 pieces of dough from 2-5 cm thickness, but with different colours of food colouring.

all the different colours of dough (fifth was a mix made from the scraps)

4.  Place all disks of dough onto plates, cover with cling wrap and place into a fridge to chill until the dough is hard and unyielding to the touch. This takes about two days. Then, take the disks out.

5. Letting the thickness of the disk be n, cut a cube with sides of n cm and a cuboid with sides of n by n/2 by 5/3n cm. For example, 1 cm thick disk would be cut into a 1 cm cube and a 1 by 0.5 by 1.7 cm cuboid. An exception is the 5cm cuboid, which will not be used as it does not fit into the displacement can.

After chilling, GRB cuts smoothly and does not stick to the knife

5.  Dust the GRB produced with cornflour.

Green 1 cm cube during dusting

from top to bottom, left to right: 5 and 3cm cubes,  3cm cuboid, 4 and
 2cm cubes, 2cm cuboid, 4cm cuboid, 1cm cube and 1cm cuboid

 6. Wrap the 3cm cube in cling wrap, gather the corners of the cling wrap and twist shut.

 7. Fill a displacement can with water, and slowly submerge the wrapped GRB while using the 100ml measuring cylinder to catch the displaced water. Record the volume and repeat steps 6-7 for the 4cm cube.

 8. Weigh and record the mass of each GRB.

Weighing the 4cm cube before cooking

 9. Using a 250ml cylinder, pour 1250ml of water  into a pot.* Put the pot on a hotplate set to 120°C and start the stopwatch. When the water has begun to boil, slowly drop all cuboid and the 1 cm cube GRB into the water by hand.

                                                                           Inserting the 1cm cube 

 10. Stir continuously with the strainer and record the time it took for each GRB to float. Turn off the hotplate when all GRBs are floating. 

Stirring with chopstick

All 5 GRBs in the second round are floating

 11. Switch the hotplate's settings to "keep warm" (70°C), and repeat step 7 (directly slipping the GRBs into the displacement can without wrapping them). Use hot water taken from the pot to fill the can.

Weighing the 4cm cuboid

12. Use the strainer to individually transfer each GRB to the scale or displacement can, then back into the pot and complete these two steps as fast as possible, before the GRB cools down.
13. Repeat steps 9-12 for the 5 GRB left.

At the end of first round, with 4 cubes cooked and rest uncooked

*Increased due to increased size of GRB, can observe sinking/floating better