4. Discussion

Analysis of results

Through this investigation , we used a total of 4 method which includes using the refractometer,hydrometer,laser pointer and the polariser.

As for the refractometer its advantages are that it is a simple method and is inexpensive,disadvantages is that it has a small measuring range and has no thermostatting. Refractometers work according to the principle that when a ray of light passes from one medium to another, the speed of the light changes according to the density of the transmitting medium.  At the interface between two media, the ray changes direction as its speed suddenly changes.  This effect is known as refraction. (France, 2014)

A good advantage of the refractometer however, is that it can handle quite opaque drinks despite being a device which utilises light to measure the sugar content of the drinks being tested.

The laser pointer advantages are that it is simple in terms of equipment. However, the mathematics has to be done almost completely manually and this can be rather cumbersome if you are looking for a quick measurement method. 
Another disadvantage of the laser method would be that if the measured liquid is too opaque for the laser to pass through cleanly, the refraction might not there for the person to see.
Some other disadvantages would be occupying too much space to carry out the 
experiment, unlike the refractometer, which is portable and only needs a source of light.(preferably natural light.)

A good advantage which the hydrometer has over ALL the other methods of measuring the sugar content of the drinks tested is that it can measure a wide range of drinks, sugar level ridiculously high or not, drink no matter how opaque - the hydrometer can handle as it does not use light as its basis of how to measure the sugar level of the drinks tested.
It uses the density of the drink as the measuring factor, however this has a disadvantage. For example, instead of sugared water,we added salt water, it will still show the readings as the Brix as it goes by density and not specifically towards sugar content. But it also has another good point, it will be able to test almost all sorts of substance for density. The hydrometer advantages are that it includes direct readings in Alcohol%, Sugar% (BRIX) or other density related values available,inexpensive method,quick(if no thermostatting is required) and simple.The disadvantages are it requires a large volume of its sample and is fragile.The hydrometer works on the principle that a floating body displaces a volume of liquid whose weight is equal to its own (Gibbs, 2013); the lighter the liquid (that is, the less its specific gravity), the deeper the body sinks because a greater amount of liquid is required to equal the body's weight.

The polarizer method is reliable and definite, providing accurate results as the setup allows us to use a strong white light source. Although liquids might be quite opaque, the polarizer method utilizes the colour of light received by the eye as the basis of the results being taken, not the position, therefore we will really have to be careful when looking through the polariser. When the polariser is not viewed from the top, the results will differ as light will bend in other ways, thus making the results inaccurate, and unreliable.

 Key findings
-We realised that there isn't a perfect method, but by taking average, we will get a result that is the most accurate. 
-After the experiments were completed,the data collected concluded that the drink “red bull” had the highest amount of sugar present. 
-Coke Zero really had 0 sugar
-The results we collected when compared to the display on the can , it is quite accurate - the most being the hydrometer method.

Explanation of key findings

As red bull has the highest sugar content as it has the highest amount of sugar /100ml according to results. 

Coke Zero has 0 sugar. However it is still sweet. From this we know some chemical substitute could have been used to sweeten the drink.

Methods using light to measure the sugar amounts of drinks are limited as some drinks are opaque.

Evaluation of Hypothesis 

Our hypothesis is correct. Red Bull indeed does have the most sugar based on the results collected from 4 different experiment setups with different methods.

Areas for improvement 

We could manage our time better. Sometimes we have the wrong priorities (e.g. doing the less important parts of the project first)
We could be more careful when transferring sugar (Polarizer method) to avoid spills
We could be more careful handling dangerous equipment such as our laser pointer and hollow prism.

We could reduce the carbon dioxide amounts in the tested liquids for better results (Hydrometer method)

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