Science Practical 4

Observing and Recording

In this practical, we were given 5 experiments to carry out, and we had to chart down our observations in a table.

*Remember to put on your safety goggles while conducting these experiments*

Experiment 1(Procedure):

 1. Pour vinegar into a clean test tube to a depth of about 1cm. 

2. Add a spatula of sodium bicarbonate.

Observation: 

The white sodium bicarbonate powder dissolved to give a colourless solution and bubbles of gas(effervescence of colurless odourless gas) were seen.

Experiment 2(Procedure): 

1. Quarter fill two clean test tubes with water. Add a spatula full of sodium carbonate to one test tube.

2.Shake the test tube until the sodium carbonate dissolves.

3. Add a dry spatula full of copper sulfate to the other test tube and shake it until the crystals dissolve.

4. Pour the contents of the second test tube into the first.

Observation:

After shaking the first test tube, the white sodium bicarbonate dissolved to give a colourless solution.

A blue solution was seen after the crystals dissolved in the second test tube.

A blue precipitate was seen when both solutions were poured together.

Experiment 3(Procedure):

1.Use an eye dropper to place one drop of methylated spirits onto the back of one hand.

2. Blow air gently across the back of your hand.

Observation:

There was a cooling sensation on the back of my hand where the methylated spirits was.

Experiment 4(Procedure):

1. Quarter fill a very small beaker with limewater.

2. Gently blow out through a drinking straw into the limewater.

Observation:

A white precipitate formed in limewater.

Experiment 5(Procedure):

1. Place a few drops of starch suspension in a clean test tube.

2. Add a drop of iodine solution.

Observation:

The iodine solution turned from yellowish-brown to blue-black due to the starch.

*Do not get iodine solution onto your skin or clothes*