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 "".

LB: How the measurements were derived

LB: How the measurements were derived

This is an explanation (using trial 1, before cooking as an example) of various techniques used to get the results. Some are self explanatory/simple enough to cover in the list of steps, and these are the rest, updated as experiments progress. Note: even though the example is trial 1, image-j was actually used until after trial 3.

1. Surface area- manual and image-j
2. Making of flats from trial 3 onwards
3. Weighing with spring balance
4. Correlation formula/Graphs

1. Surface area

I have used two ways, manually and with image-j software, to find the surface area of each GRB, though how successful each is has yet to be evaluated. In the list of steps, such a photograph was to be taken:

fom trial 1, before cooking, taken with camera held parallel from ground

Manual

Using powerpoint, a ruler and colour-coded squares encircling each GRB was superimposed onto the photograph. 

After the photo has been marked

The ruler from the original photo was to indicate the scale of the photo. The lines of the square extended until the ruler, where the diameter of each GRB is read off two times, length and width wise. Taking the average, surface area is calculated with the formulas πr² (circle) for the flats, and 4πr² (sphere) for the balls. 
Figure 1: Manual calculations for surface area before cooking, trial 1

	Radius before cooking/cm (rounded to 1 dp)
Type of GRB	Derived from length	Derived from width	Average	Surface area before cooking/ cm2 (rounded to 1 dp)
Green 40g flat	3	3.1	3.1	120.8
White 40g flat	2.7	2.9	2.8	98.5
Green 40g ball	2.4	2.5	2.5	78.5
White 40g ball	2	2.2	2.1	55.4
Green 20g ball	1.8	2.1	2	50.3
White 20g ball	1.6	1.6	1.6	32.2

Image-J

Image-J is a free, downloadable software capable of analysing images. This is the developer's website. After the photograph was opened in image-J, I used the set-scale function to declare the number of pixels in 1 cm by drawing to scale a 1 cm line on the ruler. Then, I used the free-hand drawing tool to trace the shape of each GRB and the measure function to analyse and convert into cm² how many pixels the GRB was.

Figure 2: Image-J calculations for surface area before cooking, trial 1

	Surface Area/ cm2 calculated by image-j
Type of GRB	Before cooking
Green 40g flat	32.205
White 40g flat	25.496
Green 40g ball	18.948
White 40g ball	13.867
Green 20g ball	12.027
White 20g ball	9.579

Conclusion

• Because it calculates 2D area, image-J is not applicable for the spherical GRB and there is a great difference between image-J values and manual values. So, I've decided to forgo image-j for future trials and only use the manual method.
• The "spheres" were not perfect spheres. Because of the pliability of the douch, they had no structural integrity and easily lost their shape. Hence, no more tests using round GRB after trial 1.  

2. Making of flats

After trial 1 and 2 measurements were analysed, I realised that using hands to shape the flats led to inconsistency in the shape. After talking with a friend (Zhi Rui), we came up with a way to improve that.

Diagram of the process

Before placing the spherical GRB in, the set-up is covered in cling wrap to prevent sticking.

The blocks are anything (e.g. bowls, cups, pieces of wood), but each set is identical in height and the plate has a flat bottom. This method will make the force applied more even.

3. Weighing with spring balance

Photo from real life

The GRB is placed in a plastic “pouch”, then the hook of the spring balance is forced through the top, leaving the pouch hanging. The measurement is then read off the spring balance and the mass of the plastic is assumed to be negligible.


4. Correlation formula/Graphs

Correlation was calculated with the =CORREL(array1,array2) function in excel, which uses  (pearson product-moment correlation coefficient) as the formula. This has been chosen because the data to be analysed mostly fits Pearson's assumptions that it has interval/ratio measurements, a linear relationship, minimal outliers and homoscedasticity (consistent variance along the trend line). 

example

The graphs for the final experiment are created using Apache OpenOffice instead of the previous Excel.

LB: Introduction

LB: Introduction

This is the link to the proposal for this project and this is the link for the brainstorming excel sheet. I will post tagged updates, most relevantly#lab book, as the experiment progresses. An explanation of the underlined words, usually science processes, can be found in the proposal, as well as at the bottom of this post. Do note that this journal is picture heavy, and will take time to load. 

The general structure is this: procedure, then results and discussion for each trial, interspersed with one-offs like the glossary. That said, the results post, especially for the earlier trials are going to be simple, tables and bar charts, because I don't think its worth the effort to analysis in-depth data that is known to be inaccurate. At the most, if will be to try out a particular method before using it on the final data.

The back story is that while cooking glutinous rice balls (GRBs), aka tangyuan, I've noticed that they sink initially, then float to the top as they are cooked. It's been niggling at me as to why, so when I was told to do a science project I naturally thought of this.

GBR in ginger sugar water with black sesame filing

GRBs do come in many flavours and soups, but I will be using plain flour, water and minimum food colouring, so as to distinguish samples to reduce the number of variables involved.


P.S.  

No:	Term	Meaning
1.	Gelatinisation	When starches are heated with water in cooking, individual grains absorb water and expand. This happens around 55 to 80°C, is irreversible and also increases the volume of the food,
2.	Upthrust	When an object is submerged in water, an upwards force called upthrust will acting on it and the amount of upthrust is proportional to the weight of water displaced. Hence if that object expands and displaces more water, more force will be pushing it up than before.
3.	Surface area to volume ratio	When an object expands, its surface area also becomes larger and surface area to volume ratio smaller. An increase in surface area is proportional to how efficiently it absorbs heat. Out of two foods with the same volume and mass but different shape, the food with the larger surface area will be cooked first.
	Glutinous rice	Contains more amylopectin than non-glutinous rice, exhibits properties such as an increase in viscosity ("stretchy/stickier...") and translucency after cooking. Becomes less dense.
	Correlation	Statistical relationship between two sets of data; does not imply causation

Introduction

Introduction

This blog is meant to run concurrently with a scientific experiment, as an online journal in a sense. It's "essential drafts, photographs and data" has to be "easy to follow" and honestly that is about the vaguest instructions I've heard in a while. What does that even mean anyway, bouncing cartoon tangyuans (BCTs) are banned because they're not essential? BCTs are not banned because my teacher "is not that strict"? BCTs are required to engage the reader? I really don't know.

So I've decided to split mine. Posts beginning with LB (for lab book) will be, well, the actual lab book. With aforementioned entries on experiment progress and couched in my best try at scientific language. All the other posts, e.g. this one, are rather informal.

well sorry, but I like hearing the sound of my typing, and usually ramble a lot, and can't help but think it diminishes my interest and enjoyment (and this is a student's interest-driven project) if I can't talk about the qualitative/irrelevant data like my experience conducting the experiment, yet at the same time I really am unsure about that rubric, so yeah...please tolerate., there's no need to actually read non-LB if you don't want to.

For convenience's sake there are tags as well, e.g. again, lab book. Have fun reading, good luck, and thank you!


Edit 15/7/12: from what I have seen of other's blogs and heard from my teacher, non-scientific language can be justified by wanting to be accessible to peer reviews. So yes, I also don't want to confuse anyone especially when they are already confused (sorry Charlotte).

Even if they're not the experiment, the people around you who've put up with being (repeatedly) confused are equally crucial to the project, so thank you very very much in no particular order 
Zhi Rui (reader no 1 from the get go), Kristal, Nicole, Jia Yang (yes I do in fact know I smell great like flour), Yuan An, Ms Tan, Ms Chionh, Mr Ooi , Mr Ali, Shermaine, Amy (photography skills of awesome in the classic sense), Daneel, Kellie, Jia Wen and family (oh your lovely lovely weighing scale), Laura and Charlotte and everyone else. Most importantly: Mum.