Try This at Home: Sight or Scent
Illustrated Concepts
The prefix "nano" means one billionth. At such a small scale, some tools are more reliable and useful than others.
What You Need
- 100 mL (~1/2 cup) water
- Spoon
- Eyedropper
- Graduated cylinder or measuring spoons
- 1 mL (1/4 teaspoon) colored mouthwash (or colored water with a drop of vanilla or perfume added)
- 10 identical small cups or an ice cube tray
What To Do
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Make sure you have an adult with you to supervise this experiment.
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Line up the nine cups in a row and label them 0 through 9.
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Fill Cup 0 with 10 mL (2 teaspoons) water.
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Fill Cup 1 with 9 mL (1 3/4 teaspoons) water and 1 mL (1/4 teaspoon) mouthwash. Stir.
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Fill Cup 2 with 9 mL (1 3/4 teaspoons) water and 1 mL (1/4 teaspoon) solution from Cup 1. Stir.
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Fill Cup 3 with 9 mL (1 3/4 teaspoons) water and 1 mL (1/4 teaspoon) solution from Cup 2. Stir.
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Observe the color and scent of the mixtures in Cups 1, 2, and 3. Are they the same? Make a hypothesis! How do you think the mixture in Cup 9 will look and smell?
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Fill the remaining cups in the same manner used to fill Cups 1, 2, and 3.
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Compare the colors and scents of Cups 0, 1, and 9. Can you see which cups contain mouthwash? Can you tell the difference by smell?
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Clean up.
What's Happening
By adding water to the mixture, you are diluting the mouthwash. Cup 0 contains 100% water for comparison. Cup 1 contains 10% mouthwash, Cup 2 contains 1% mouthwash, Cup 3 contains 0.1% mouthwash, etc., Cup 9 contains one billionth of a percent mouthwash. We call one billionth of something "nano", so you can think of Cup 9 as containing one "nano-percent" mouthwash. Similarly, one nanometer is a billionth of meter. Nanotechnology concerns science on this tiny scale.
When working on such a small scale, scientists' hands and eyes are simply too big to handle these tiny particles. They need special tools, such as magnets, light beams, and electron microscopes, to be able to work with nanoparticles. Similarly, our eyes are unable to be sure of which cup contains the mouthwash when comparing Cups 0 and 9. However, our more sensitive noses can sniff out the scent of the mouthwash much more reliably.
In order to create objects on the nanoscale, scientists can use either a "bottom up" or "top down" approach. The "bottom up" approach means building nanostructures one atom at a time. The "top down" approach means cutting a large structure down until it is very small. Our experiment follows that "top down" approach because we took a significant amount of mouthwash and diluted it until it was on the nanoscale. Scientists are also research methods of self-assembling nanostructures. Imagine shaking a box of Legos and having some of the Legos stick together in the process. In this analogy, each Lego represents an atom. By shaking the box the individual atoms clump together to form nanostructures without the intensive help of an outside resource.
Fun Fact
Our hair and fingernails grow about a nanometer every second!