Procedure

Today I have written my procedure of how I will carry out my experiment before i start,
Procedure
1.Take out all your equipment needed and add 300ml of water into the saucepan.
2. Weigh 20g of salt and add into the saucepan
3.Bring the solution to boil and measure the temperature at boiling.
4.Record temperature at boiling point, replace the solution with clean water and varying amounts of salt
5.Repeat the above procedure with the following amounts of salt 20g,40g,60g,80g,100g.

sample table of results and graph

These are some draft tables of what my results will look like and how i will record my observations

Temperature of water at boiling point containing salt

Hypothesis, aim and equipment list

Hypothesis:
If adding salt to water is related to the boiling point, adding more salt into the solvent which is the pure water, the temperature will be higher than 100°C.
Aim :
To prove that the concentration of salt in water will affect its boiling point.
Equipment list:
-Saucepan
-Thermometer from 50°C to 200°C
-Salt
-Tap water
-stove

Variables

Independant variable
In order to investigate the concentration of salt and how it will affect the boiling point of water, I will start with changing the amounts of salt in the water. The thing I will manually change is the grams of salt, so this becomes the independant variable.

Dependent variable
In my experiment which is to prove the concentration of salt and how it will affect the boiling point of water. I am deciding to change the amounts of salt to put into the water and measure how long it will take for the water to boil with the different amounts of salt. I am also measuring the temperature of the water as it boils. Therefore, i will be measuring the temperature of the water, this becomes my dependent variable.


Controlled variable
In my experiment I will be manually changing the amount of salt in the solution of clear water. I will be measuring the temperature of the water as it starts to boil. In every test the heat on high, the total quantity of the solution, the thermometer used and the same saucepan for the water will remain the same.

Why I have chosen to carry out this experiment

I have chosen this idea as it is relevant to everyday cooking, also, I enjoy cooking and it would be interesting to know the effects of salt and the boiling point of water. It was also chosen because the experiment is able to be done with general household utensils such as salt, saucepans etc. My initial research, through the internet has made me intrigued into this topic, as well as talking to a family relative who is an italian chef, which from him telling me about the use of salt has made me more curious about conducting this experiment. The reason why I had not chosen the idea of testing the various strengths of glues is because I have younger siblings and it would be quite dangerous having many glues around the house, the idea of gas ovens are more efficient than electric would also be unsafe because when carrying out the experiment it might burn and would need an adult supervision while with the salt experiment it would be easy to conduct it by myself. As well as testing what type of tablet dissolves the quickest, it would be very dangerous if my siblings would grab the different types of tablets and would swallow it and there would be a risk of choking. I am very excited to complete this experiment and to see if my predictions would be correct. 

A bit more research

http://itotd.com/articles/521/water-freezing-and-boiling-myths/

• This point is a very true fact, when adding Salt. Salt which is the solute does raise the pure water’s boiling point and it also lowers the freezing point of water (which is why most homemade ice cream makers use rock salt). But the real question is whether this makes it take longer to get to the boiling point.
• Despite what you read in cookbooks, scientists claim that the amount of salt you’d typically add to a pot of boiling water is too small to make any meaningful difference in the boiling time or boiling point.

http://www.newton.dep.anl.gov/askasci/chem03/chem03336.html

• Adding salt to water will always raise the boiling point. This is the reason why many recipes call for the addition of a small amount of salt to boiling water. The salt causes the water to “cook” what’s in the water for example when cooking pasta

• The addition of salt does not only raise the boiling point of water but it also lowers the freezing point of water. Which is why in winter people put salt on their steps and walkways.

• Water under pressure will also have a higher boiling point temperature

http://www.physlink.com/education/askexperts/ae643.cfm

• In order for something to boil, enough energy has to be absorbed by it to cause large vibrations to magnify the kinetic energy of each molecule, to the point where they break away from forces that hold them together in the pure liquid.

• When a solid is dissolved into a liquid, the energy goes into each water molecule to a higher kinetic energy but also each salt molecule to a higher kinetic energy as well.

• The salt molecules need to be large, this takes away most of the water molecules.

• The density ends up needing more energy for the same amount of energy as the salt and it would lead to the boiling point of water.

• The salt molecules weigh down the water molecules.

http://www.ehow.com/about_4571070_salt-do-boiling-point-water.html

• Adding salt to water raises the boiling point of water as well as lowering the freezing point of water. 
• salt chemical ions take up some space and it makes fewer crashes amongst the water molecules as pure water would.
• More energy is required as well as higher temperature and salty water to start boiling.

My response from CSIRO

8.2.11
Today CSIRO had finally replied to my email. They said they couldn't give me some of their own information but they had sent me five internet links to help me, I really appreciated their help. These are the links they attached:

·         http://www.animations.physics.unsw.edu.au/jw/freezing-point-depression-boiling-point-elevation.htm

·         http://www.abc.net.au/science/articles/2007/04/12/1894612.htm

·         http://itotd.com/articles/521/water-freezing-and-boiling-myths/

·         http://www.sciencebase.com/science-blog/how-does-salt-affect-the-boiling-point-of-water.html

·         http://www.newton.dep.anl.gov/askasci/gen01/gen01021.htm

Some primary research

6.2.11

The idea that I have chosen to conduct is the concentration of salt and how it will affect waters boiling point. Today I have done some primary research to learn a bit about salt and water. 

Research on my chosen idea:

http://www.sciencebase.com/science-blog/how-does-salt-affect-the-boiling-point-of-water.html

•   Dissolving salt in a liquid, like water,  when dissolving one substance which is known as the solute, in this case the salt, into another solvent which is the water, it will raise the boiling point of more than 100℃.

•   The degree of the water changing depends on how much solute you dissolve in the liquid. The temperature of the water does not change relying on the type of solute.

•   If the salt is dissolved in the liquid (water), the number of water molecules weaken and are overtaken by the particles of the salt. The vapour pressure of the solvent lowers which means that there needs to be a higher temperature to boil the water with the salt solution.

•   When carrying out this experiment keep the heat source constant.

http://www.newton.dep.anl.gov/askasci/gen01/gen01021.htm

•   As soon as any of the salt dissolves in water, the boiling point rises by about 1½℃ for every 58 grams you put in of salt.

•   Not only salt, but any non-changeable substance will raise the boiling point of water.

•   Small amounts of salt added will be completely dissolved before the bubbling begins to occur. The salt water will need to be exposed to more heat than the pure water to boil. The salt water will boil slower than the pure water.

http://martinz.wordpress.com/tutorial/salt-and-the-boiling-point-of-water/

•   Salt, or other solutes, such as sugar can easily dissolve in liquids especially water. But, when taking out the solute which is salt out of the water and putting it into the air it needs a lot of energy. 

•   Now the total pressure in the liquid and the air at the boundary are the same- otherwise one would push the other into a smaller space. Part of the pressure in the liquid comes from the solutes, not the water. So the pressure due to the water alone is reduced compared to that of pure water at the same temperature. The vapor pressure, that is, the pressure of water vapor that would stay in equality with the liquid, is reduced by the same amount because of the solutes.

•   Water boils when the vapor pressure of the water gets to be as big as the pressure of the atmosphere. At that point, vapor bubbles in the water can grow. You have to heat the liquid with solutes up more to get the vapor pressure in it to equal the atmospheric pressure, so it has a higher boiling point.

•   A very similar argument explains why solutes also lower the freezing point. Since the solutes are almost completely excluded from the solid (like from the gas) they stabilize the liquid. A search of this site will turn up some answers about freezing salt water.

•       Today I also emailed the commonwealth Scientific and industrial research organisation (CSIRO) and I had asked them for some research and links for my chosen topic. They said that they will email me in approximately two business days.

Brainstorm of Ideas

Today I have decided to do some brainstorming and create a mind map of some of the ideas I would like to do for my SRP.