Testing for Protein

The Biuret test

Aim:
To test if a sample of food contains protein.

Equipment:
- Test tube
- Sodium Hydroxide
- Copper sulfate
- Food sample

Method:
1. Place about 2 mL of the sample into a test tube and add 5 drops of sodium hydroxide.
2. Add 5 drops of copper sulfate.
3. Shake the test tube gently from side to side.

Results that may happen:
If the solution remains blue, then no protein is present. If the solution changes to a violet colour then protein is present in the sample.

Conclusion/discussion/Results:
Our first experiment failed due to too much milk. Second try also failed, even we heated it. If it had any protein it should've changed colour from blue to violet. By adding sodium hydroxide and copper sulfate, the sample turned to blue colour. After shaking the sample it changes colour, it means it has protein.

Testing for simple and complex sugars

The Benedicts test 

(Simple sugar test)
Aim: To test a sample of food determine whether it contains simple sugars.
Method:
1. Place about 2 mL of the sample into a test tube and then add 5 drops of Benedict' Solution.
2. Heat with a bunsen until it changes colour. Do not Boil

Results: A positive test for a simple sugar results in the Benedict's Solution changing from a blue colour to a orange colour.
No colour change is a negative result.

Discussion/Conclusion:
If the benedict changes colour it means that the food sample was a simple sugar. If it's not a simple sugar the benedict would stay the same colour.
We tested the sample and it turned what we had in our mind. It contained the simple sugar.
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(Complex Sugar test)
Aim: To test if a sample of food contains complex sugars.
Method:
1. Place about 2 mL of the sample in a test tube.
2. Add 3-5 drops of iodine and mix.

Results: If comlex sugar (Ex: Starch) are present the Iodine solution will change from a brown colour to blue/black colour. If the iodine solution does not change colour then no complex sugars are present.

Discussion/Conclusion:
If the iodine changes colour it means the sample contained complex sugar. If it stayed the same it doesn't contain any complex sugar. We tested the sample and it turned what we had in our mind. It contained the complex sugar.

Convection

Aim:
To observe convection in a liquid.

Method:
1. Set up a Bunsen burner on a heatproof mat. Put the gauze maton the tripod but leave it just to one side of the bunsen burner.
2. Fill a 200mL beaker with 150mL cold water.
3. Place the beaker on top of the tripod and gauze and allow it to settle for a few minutes.
4. Carefully insert a drinking straw down one side of the beaker, ensuring the straw is touching the bottom of the beaker. Be careful as you do not want to disturb the water too much.
5. Using tweezers, drop a crystal of potassium permanganate down the side of the straw. Wait for the crystal to settle on the bottom of the beaker.
6.Very gently, so to not disturb the water, remove the straw.
7. Light the bunsen and slide it under the tripod so that you are only heating the outside of the beaker where the crystals is. Observe.

Results:
The potassium permanganate particles turned the water purple as we heated the beaker. The purple liquid raised up.

A Video Of The Result:

Discussion:
In this experiment the hot liquid was the potassium permanganate. The hot water rises because it is less dense. 

Particle Theory of Matter

Aim: 
To observer conduction along a metal rod.

Equipment:
A metal, Retort stand and clamp, Bunsen Burner, petroleum jelly, 5-10 drawing pins, a stopwatch.

Method:
1. Set up and light a bunsen burner.
2. Smear a small amount of petroleum jelly on the head of each drawing pins.
3. Attach the drawing pins at even intervals along the length of the metal rod.
4. Clamp one end of the metal rod to a retort stand.
5. Position the retort stand so the unclamped end of the metal rod is in the bunsen flame and start the stopwatch.
6. Record the time it takes for the each pin to drop in the table below.

Results:

Pin Number	Time to drop (s)
Pin 1	8.63
Pin 2	43.68
Pin 3	1:00.89
Pin 4	2:10.03

Discussion:

This is how each pins drop. The first pin was the closest to the heat so It falls off first. A solid has a small gaps between their particles so the movement is vibrating. The vibrating transfer to each particles until it reaches the last pin.

The Behaviour of Matter - Expansion

Aim: To observe diffusion in a liquid.

Equipment:
- Petri dish
- Water
- Tweezers
- A crystal of potassium Permanganate

1. Half fill your petri dish with cold tap water.
2. Place the petri dish on your workbench and allow the water to become settled.
3. Using the tweezers, place a single crystal of potassium permanganate in  the center of the petri dish.
4. Observe for 5 minutes.
5. Repeat the experiment with hot water.


Results Hot water = Video

Cold water = Picture

Discussion:

Cold water - We put a little bit of potassium permanganate in the middle of the petri dish. It was first high concentrated in the middle and after a while it went to low concentration but it spreads throughout the petri dish. It spread slowly throughout the petri dish.

Hot water - We put a little bit of potassium permanganate in the middle of  the petri dish. It was first high concentrated in the middle but almost instantly it spread throughout the petri dish like it was running. When heated, the particles starts running because it's like putting fire under their feet.

Investigating state changes

Aim:
To observe water as it changes state from solid to liquid then to a gas.

Equipment:
- A 250 Ml beaker
- Thermometer
- Bunsen burner
- Heatproof mat
- Tripod
- Gauze mat
- Stopwatch
- Retort stand
- Clamp
- Ice cubes

Method:
1. Collect enough ice so that your beaker is half full and place the thermometer into it while you set up the rest of the equipment.

2. Set up the retort stand and clamp alongside the tripod and gauze mat.

3. Place the beaker of ice on the gauze mat and gently clamp the thermometer so that it is held upright and the scale is easy to see. The bottom of your thermometer should be low enough to still be covered by water when the ice melts, but not touching the bottom of the beaker.

4. Record the initial temperature of the ice in the date below.

5. Light the bunsen burner and start timing with the stopwatch.

6. Measure and record the temperature every minute.

7. Continue measuring and recording the temperature until the water has been boiling for 2 - 3 minutes.

Results:

Temp ( OC)	Time (Minutes)
6	1
11	2
12	3
17	4
26	5
40	6
60	7
78	8
92	9
106	10

Discussion:

We first heated up the block of ice (Solid). The first temperature that we got was 5 degrees. After a while it got higher and higher. The fastest gain of temperature was at 7 minutes and the slowest gain of temperature was at 3 minutes. When we got to 5 minutes, all of the solid turned into a liquid. At 10 minutes, the liquid started to evaporate and the liquid turned into a gas. 

Chromatography

Aim:
To seperate the different pigments in inks using paper chromatography.

Method:
1. Cut a piece of filter paper long enough to reach the bottom of your test tube.
2. Rule a line in pencil 2cm from the bottom of paper.
3. Fill the test tube with 1cm of chromatography solution (water)
4. Place a dot of ink above the ruled line.
5.  Fold over test tube and place in solution.
6. Wait and observe
7. Repeat with 2 other colours.

Results:
The liquid climbed up the paper, reaches the ink circles and it touches the ink, the ink is slowly spreading throughout the paper. 

Discussion:

We draw a circle out of ink felts on paper filter. We carefully put it in the test tube with 10ml of water. After a while the ink started to spread around and mixing in with the other colours. This method is called Chromatography.

Evaporation

Aim:
Aim: To seperate a solute from a solvent in a solution using evaporation.

Equipment:
- Copper sulfate Solution
- 250 mL beaker
- Heatproof mat 
- Evaporating basin
- Bunsen burner
- Tripod
- Gauze mat

Method:
1.  Set up the bunsen burner, tripod and gauze mat. Don't place the bunsen burner under the tripod yet.
2. Add approximately 50 mL of how water to your beaker and place it on top of the tripod, on the gauze mat.
3. Add enough copper sulfate solution to quarter fill the evaporating basin.
4. Carefully place the evaporating basin on top of the beaker.
5. Light your bunsen burner. Open the air hole and gentle push the bunsen burner under the tripod.
6. Heat the solution until most of the solvent has been evaporated and crystals  of solute are forming.
7. Turn off your bunsen burner.

Results:

All of the solvent is evaporated and all that is left is the solute.

Discussion:

After the evaporation of the solution and all of the solvent evaporated all of that's left is the solute which is the blue crystals.

Separating a mixture using Distillation.

Aim: To separate a solute from a solvent in a solution using distillation.

Equipment:
-  Coke, conical flask, heatproof mat, a delivery tube and bung, bunsen burner, tripod, gauze mat, retort stand, boss head clamp, boiling tube.

Method:
1. Set up the equipment as shown in the diagram.
2. Add approximately 50 mL of coke into your conical flask.
3. Light your bunsen burner. Open the air hole and gently push the bunsen burner under the tripod.
4. Heat the solution until most of the solvent has been evaporated. Turn off your bunsen burner.

Observations:
While we were boiling the coke, a stream of steam came out after a while water was going up and was traveling through the delivery tube into the beaker.

Results: 
The coke was evaporating into the delivery tube and was traveling into the beaker and turned into water.

Discussion:
The solution (Coke) was evaporating and the solvent was turned into a gas. The gas has now transferred into the conical flask that are full of ice and the gas was condensing into liquid. During the experiment, we didn't have time to finish it so if we had more time, all that would be left in the conical flask is the solute (Black sugary stuff). This method is called "Distillation".