Transcript
PREPARED BY
NAME ID NUMBER
NORHAFIZAH BINTI NORDIN D20101037456
NURSYAHIRA AYUNI BINTI AHMAD ZAMRI
D20101037457
AIN NABILA BINTI ABD. MALEK D20101037463
ENGAGE
• These two nails were located at same place.
• Nail A was immersed in salt water while nail B was
immersed in plain water.
• Which nails will more corrosive?
Nail A Nail B
Questions
From the situation, what
happen to both nails?
Which nail is more
corrosive? Why?
Can you explain?
EMPOWER
Figure 1: Design of the experiment
Computer
Nail A
Salt water
Test tube
Stopper with
delivery tube
Retort stand
Plan of the experiment
Objective
• To investigate the effect of salt on the rate of corrosion.
Hypothesis
• Salt water increase the rate of corrosion
Variables
• Manipulated variable: Type of water
• Responding variable: The rate of corrosion
• Fixed variable: Temperature
Plan of the experiment
Apparatus
• Nails
• Salt water
• Plain water
• A delivery tube
• Cork
• Pressure sensor
• Retort stand
Plan of the experimentMethods
1. Prepare 2 test tubes labeled A and B.
2. Set up the apparatus as shown in Figure 1.
3. Place a nail in each test tube.
4. Pour salt water in test tube A and plain water in the test
tube B.
5. The water is pored until it overflow from the test tube.
6. Insert the stopper with delivery tube.
7. Make sure there is no air bubble in the test tube.
8. Connect the pressure sensor at delivery tube.
9. The pressure sensor is connected at computer.
10. Measure the pressure change of both test tube over 7
days.
Plan of the experiment
Result
0
0.5
1
1.5
2
2.5
0 2 4 6 8
Pre
ssu
re (
Pa)
Days
The rate of corrosion
salt water
plain water
Plan of the experimentDiscussion
• Based on the result, nail A that immersed in salt water ismore corrosive than nail B that immersed in plain water.
• This is because, oxygen present in water and salt causescorrosion. Salt is hygroscopic in nature and it attracts thewater. Water is required for corrosion and salt speeds upthe process.
• The salt speeds up the corrosion by improves thecapability of water to carry electron through redoxreactions.
• Rusting in metals undergoes an electrochemical process inwhich iron loses electrons by oxidation causing the waterto break into hydroxide ions and oxygen. The metal thathas oxidized reacts with the hydroxide ions and oxygen toform metal oxide. These salts remain even if the water isgone and they again start rusting whenever they come incontact with moisture.
Plan of the experiment
Conclusion
• The salt water increase the rate of corrosion compare
with plain water.
ENHANCE
• From the above pictures, predict the condition of gate
after 10 years based on the locations?
• Give the reasons to support your predictions.
• Explain the changes process.
A- House at Pantai Teluk Lipat B-House at Putrajaya