06. Rusting

Outcomes:

- Generate a hypothesis for an investigation into rusting.

- Carry out a fair investigation into the factors that affect the rusting of an iron nail.

What causes something to rust?

In this investigation you will set up a simple experiment to test different conditions, to see which ones can cause the most/least rusting of a simple iron nail.

Any investigation should start with a hypothesis, that your investigation can test.

When we look at the details for Criteria B assessments:

"At the end of year 5, students should be able to:

ii. formulate a testable hypothesis and explain it using scientific reasoning"

(MYP Science Guide, from 2014)

At the 5-6 level this is expanded to:

"ii. formulate and explain a testable hypothesis using scientific reasoning"

and at the 7-8 level is is:

"ii. formulate and explain a testable hypothesis using correct scientific reasoning"

So, you have 8 mins to do some research into the "correct scientific reasoning" that could support your hypothesis about what might affect how much an iron nail rusts.

Bitesize 1 Doc Brown Bitesize 2 YouTube s-cool

Now you need to write your hypothesis.

Any "correct scientific reasoning" that you use MUST be cited. That means MLA8 and an in-text citation!

Based on your hypothesis you now need to set up a simple experiment to investigate the different conditions that might affect how much an iron nail rusts.

Apparatus - choose from:

    • tap water

    • salt water

    • boiled water

    • distilled water

    • magnesium ribbon

    • cooper wire

    • grease (vaseline)

    • cooking oil

    • cobalt chloride paper

You should use 5 test tubes, each one should contain an iron nail. Each one should be sealed with a bung so the conditions remain constant.

Method:

    1. Set up one test tube as a control experiment. This will be the one that you compare all your other experiments to. It should contain the optimum conditions needed for a nail to rust.

    2. Set up four other test tubes with different conditions that will affect how much the iron nail will rust.

    3. Make predictions about what you will see happen in each test tube.

    4. Take a photo of your equipment set up and upload it to the padlet site.

Results and Conclusion:

Your results will be a comparison of before and after photos of the iron nails.

Your conclusion will be presented as a "visual presentation" (you can choose what format you use to generate the poster).

When we look at the details for Criteria C assessments:

"ii. interpret data and explain results using scientific reasoning

iii. evaluate the validity of a hypothesis based on the outcome of the scientific investigation"

(MYP Science Guide, from 2014)

At the 5-6 level this is expanded to:

"ii. accurately interpret data and explain results using scientific reasoning

iii. discuss the validity of a hypothesis based on the outcome of a scientific investigation"

and at the 7-8 level is is:

"ii. accurately interpret data and explain results using correct scientific reasoning

iii. evaluate the validity of a hypothesis based on the outcome of a scientific investigation"

To help you achieve your target in these areas, answer the following questions and incorporate them into your poster:

  • How many moles of iron is in the nail? (nail = 2.5g)

  • How many grams of iron oxide could this make 2Fe --> Fe2 O3 ?

  • What is the atomic structure of an iron atom (protons, neutrons, electrons etc..)

  • Iron makes Fe3+ ions, how did they do this?

  • Describe the bonding and attraction in Fe2 O3 .

  • Compare the properties of Fe2O3 to a covalent structure like water and oxygen. (Molecules, inter-molecular forces, ionic lattice etc..)

  • Balance the rusting equation _Fe + _O2 --> _Fe2 O3

Next lesson: 05. Clean water