Oil spill

Use science to fight pollution!

Difficulty:
Danger:
Duration:
10 minutes
Oil spill

Safety

  • Perform the experiment on the underlay and use protective gloves to avoid staining your hands.
  • Carefully review the general safety advice in the instruction book before starting the experiment.

Step-by-step instructions

Wear protective gloves and use the waterproof underlay to keep your table clean. Open the bottles you’ll need before starting the experiment. You will need some vegetable oil.

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Prepare a mixture of vegetable oil and graphite particles. It will physically resemble petroleum in color, consistency, and the solubility properties of its components.

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Due to its hydrophobic properties and relatively low density, vegetable oil tends to spread over the surface of the water just like real petroleum.

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Ordinary felt absorbs both water and oil, which makes it rather ineffective in cleaning the contaminated water.

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Meanwhile, hydrophobic felt absorbs only the oil, making it much more efficient in ridding the water of pollution.

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Disposal

  • Dispose of solid waste together with household garbage.
  • Pour liquids down the sink. Wash with an excess of water.

Scientific description

The forces of attraction between the molecules of two distinct liquids determine how they behave when mixed. If the forces are weak, the liquids tend to reduce their area of contact with each other as much as possible. The densities of the liquids also affect their behaviors: less dense liquids tend to float on top of denser ones.

Since oil  is hydrophobic and less dense than water , a droplet of oil will not spread out through a body of water; it will remain on the water’s surface. Similarly to water, oil also has materials that soak it into their surfaces and materials from which it can be easily eliminated. The nature of each individual material determines which kinds of liquids it can absorb.

As ordinary felt  soaks up both water  and oil , it can’t remove oil from water efficiently. Meanwhile, hydrophobic felt  interacts weakly with water , as you saw in the first experiment – but it turns out that it is quite capable of absorbing oil . This allows us to separate the oil from the water, effectively removing this pollution.

Real petroleum  has similar characteristics to the oil  used in this experiment – it floats on top of water  and is readily attracted to various hydrophobic materials. Exploiting this aspect of hydrophobicity can help us eliminate petroleum from the surface of the sea.