Thermometer

I finally found a thermometer that was suitable to use!!


http://www.dse.com.au/cgi-bin/dse.storefront/4c04a95402f24b1e2743c0a87e010624/Product/View/Y5118

I had to go all the way to Hurstville to get it.

SRP here I come!

Method For Sugar Experiment

Aim: To investigate whether the concentration of sugar in water has an effect on the freezing rate of water.

Materials: 4 x 200 mL water
400g sugar (to be split into three quantities of 66g, 134g and 200g)

Equipment:

• 4 plastic cups
• Freezer(set at -18°C)
• Timer
• Thermometer
  

Method:

1. Distribute materials into cups as follows:

• 1 x tap water
• 1 x tap water mixed with 66g of sugar
• 1 x tap water mixed with 134g of sugar
• 1 x tap water mixed with 200g of sugar

2. Measure the temperature of each of the solutions and alter temperature if needed to ensure a fair test.

3. Place all cups inside the freezer and begin timing.

4. Measure the temperature of the water at intervals, beginning with 20 minutes and decreasing as the solutions are near freezing point.

5. Record all data and observations.

6. Stop measuring once all 4 solutions have frozen.

7. Repeat steps 1-6 at least 3 times.

Variables

A list of variables for my sugar experiment:

Independent Variable:
1. The quantity of sugar in each cup.

Dependent Variable:
1. How long each solution will take to freeze.

Controlled Variables:
1. The temperature of the freezer.
2. Temperature of the solutions.
3. Amount of time the cups are in the freezer
3. Quantity of solutions in the cups.

Types of Sugar

During the experiment I will be using sucrose.

Sucrose is commonly known as table sugar. According to Wikipedia; "The molecule is derived from glucose and fructose with the molecular formula C₁₂H₂₂O₁₁."

According to http://www.3dchem.com/molecules.asp?ID=59, sucrose is a disaccharide; "Disaccharides are compounds that contain a bond between carbon(1) of one sugar and a hydroxyl group at any position on the other sugar.

Sucrose, ordinary table sugar, is probably the single most abundant pure organic chemical in the world and the one most widely known to nonchemists. Whether from sugar cane (20% by weight) or sugar beets (15% by weight), and whether raw or refined, common sugar is still sucrose."

Climate Graph

Useful Sites

http://www.worsleyschool.net/science/files/saltandfreezing/ofwater.html - explains about what happens to the molecules in the water during the freezing process.

http://www.newton.dep.anl.gov/askasci/env99/env133.htm - explains about ions in the water, info about crystal formation during the freezing process.

http://www.scienceproject.com/projects/intro/primary/PX071.asp - project.

http://en.allexperts.com/q/Oceanography-2135/salt-water-freezing-1.htm - explains from a chemistry-ish perspective why the salt water lowers the melting and freezing temperatures of the water.

http://www.picotech.com/experiments/freezingofwater/freezingofwater.html - experiment info.

Variables for Saltwater/Pure Water Experiment

If I were to go ahead with the freezing of saltwater vs pure water experiment, the variables would be as follows:

Independent Variables:
1. Amount of time in freezer
2. Quantity of water
3. Temperature of water
4. Salt/sugar/vinegar/nothing in water
5. Temperature of freezer

Dependent Variables:
1. How quickly the temperature drops
2. How quickly each of the cups of water freezes