Name Jack Forrest
Date__________
Period__3____
Forming the Investigation
Manipulated Variable (I change)
independent: Type of coating on the steel
nail
Response Variable (I measure)
dependent: Amount of corrosion on
the nail
1. What is the question I will answer with this investigation?
Which coating will most prevent a steel nail from corrosion over five days in a moist
environment, Magnesium coating, or zinc hot dipped coating?
2. Background Information: Several things I already know about this topic, that will
help me to design a successful investigation, are
• Steel will rust in a damp enclosed environment after four days
• Magnesium will rust in a water no air environment, and a water and air
environment.
• Zinc will rust in a water no air environment, and a water and air environment.
• Oxygen must be present for corrosion to happen whether it’s in the form of
water or air.
• Magnesium has only two valence electrons, which makes it a very reactive
metal.
• Zinc slowly reacts with air.
• With two valence electrons, magnesium can give these electrons to oxygen
that needs two more electrons to make a full outer shell with only six valence
electrons making them very reactive with each other.
3. Predict in words what I think will happen during my investigation (hypothesis).
Then, use the graph to sketch my predicted results.
I predict that the magnesium coated nail will make the steel nail underneath corrode
the least because even though it is more reactive than zinc I think that it will sacrifice
itself and it will corrode instead of the nail underneath.
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Name Jack Forrest
Date__________
Period__3____
Designing the Investigation
Variables I will keep the same for a fair test:
Same amount of water
= 5ml
Same water
= Tap water
Layers of paper towel
= 3 layers
Same place
= Classroom
Same type of nail under
Coating
= Steel
Amount time to let
The nails corrode
= 5 Days
=
Safety: Do not eat any materials, be careful of sharp areas around the nails, and wear
your goggles around dangerous substances.
Materials: Paper towel, Zinc hot dipped coated steel nail, Magnesium coated steel nail,
Steel nail, tape, Petri dish with top, post it note, 5ml of water, scissors.
Numbered and detailed procedures with a drawing of my set-up.
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
Gather materials
Fold paper towel into 3 layers
Cut the folded paper towel into a circle with an 8cm diameter
Place the circular paper towel into the Petri dish
Dampen the paper towel in the Petri dish using 5ml of water and pour it over the paper towel
evenly
Place an uncoated steel nail on the inside of the Petri away from the wall of the Petri dish
Place a zinc hot dipped steel nail inside the Petri dish but away from the Petri dish wall and the
other nail
Wrap a steel nail in a strip of magnesium covering as much of the nail as possible and place
this nail in the Petri dish but away from Petri dish wall and the other two nails
Record your observations of the three nails immediately after placing the nails in the Petri dish
in the appearance before experiment box in the table on the next page (record)
Place the top of the Petri dish on top and use tape to tape the top onto the Petri dish covering
the whole lip of the top over the Petri dish
Let the Petri dish sit out in the classroom for 5 days with the nails, paper towel, and the top
taped on it
After the five days, record your observations of the nails in the appearance after experiment
box in the table on the next page
Write a conclusion for each nail about the observations you made in the table on the next page
in the “rating of corrosion of nail under coating and conclusion”
Determine an appropriate rating for each nail based on the amount of corrosion the nails have
sustained over the five-day period. (Use the table provided on the next page titled “Corrosion
Rating Table” to help you determine your rating
Clean up your supplies and make sure to put the nails and paper towel in the garbage and wash
out the Petri dish
2
Name Jack Forrest
Date__________
Period__3____
16. Collecting and Presenting Data
Title: Rating and appearance before and after experiment
Coating
Appearance before
experiment
Appearance after
experiment
No coating
Shiny, hard, silver,
smooth
Zinc coating
Rough, gray, dull,
parts are shiny under
Magnesium coating
Shiny, silver, some
black areas, smooth
Nail rusted a lot on
bottom area, bleed
through on paper
towel
Mostly zinc oxide
which is white and a
solid, but rust shown
through on actual
nail
The nail inside the
wrapping has some
brownish orange rust
in small patches
around it. The
magnesium started
to develop a white
solid (magnesium
oxide)
Rating of corrosion
of nail under coating
and conclusion
A steel nail by itself
will corrode over five
days. Rating: 4
A zinc covered nail
will partially corrode
over 5 days
Rating: 3
A magnesium coated
nail will barely
corrode over 5 days.
Rating: 2
Title: Corrosion rating table
Rating
0
1
2
3
4
Amount of corrosion based on rating
No rust at all
Just barely any rust
Couple patches of rust
Respectable amount of rust
Lots of rust, bleeding into paper
towel
Rating based on amount of corrosion Rating based on amount of corrosion for each nail coating 5 4 3 2 1 0 steel nail magnesium Coating on nail 3
zinc Name Jack Forrest
Date__________
Period__3____
Analyzing and Interpreting Results
Question: (from p. 1)
Which coating will most prevent a steel nail from corrosion over five days in a moist
environment, Magnesium coating, zinc hot dipped coating, or no coating?
Introductory Sentence: In this investigation I observed a steel nail, coated in magnesium,
hot dipped in zinc, and no coating over 5 days in a moist environment to see which coating
will most prevent the steel nail under that coating from developing rust.
1. Evidence
In our investigation of seeing how well
different coatings would prevent
corrosion on a steel nail,
I found that the magnesium coated nail
worked the best preventing the steel nail
from developing iron oxide in a moist
environment over five days.
For example on a scale of 0-4, the zinc
coated nail received a 3 on amount of
rust, and the control a 4, the steel nail
under the magnesium received only a 2
because of its low amount of rust.
3. Problems
One problem during this investigation
was that my control did not actually
rust as much as it should have. The
reason for this is unknown but it is
possible some coated nails were mixed
in to the control nail box.
This would have caused our data to be
lower because if I were to have used
that nail I would have thought that
steel by itself does not rust as much
zinc coated nail and a magnesium coated
nail.
2. Explanation:
The reason we got the results we did was
because magnesium and oxygen form a
perfect ionic bond and because magnesium
has two valence electrons while oxygen as
six valence electrons. This makes MgO
(magnesium oxide). The magnesium basically
sacrifices itself to the effects of
corrosion and not the steel. The reason the
zinc coating got second was because it is
less reactive then the control (steel)
making a shield against corrosion but the
zinc did not fully cover the nail and had
many small gaps exposing the steel to the
moist environment creating the iron oxide.
4. Conclusion
In conclusion, our results show
that the magnesium coated nail did not
corrode at the same extent as the
control nail and the zinc coated nail.
A future experiment or revision we
could do is try another reactive metal
nail and compare that to the magnesium
coated nail to see if what happened in
this experiment could happen again.
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