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Science progress affects our daily life and "to know" means you are going to chose right, because it allows you to form your own opinion on scientific everyday issues. On the other hand, having an elegant and harmonious vision of the world where we live in leads to a feeling of intellectual satisfaction.
We believe this kind of scientific day to day knowledge should be encouraged from an early age, and that's why this project was born: science, culture, knowledge, crafts for your restless mind.

Tuesday, November 29, 2011

The air takes space- Try this

Another simple and basic science demonstration. Restless Minds already played with air a few times, check it out.

What we need:
  • flask with lid, metallic works best,
  • nail,
  • hammer,
  • straw,
  • molding clay,
  • water.
How to do it:
  1. Use the nail, and with the hammer punch a hole on the lid big enough for the straw. Don't let your child use the hammer;
  2. Fill the flask with water to 2/3, you can use juice;
  3. Close the flask with the lid;
  4. Place the straw in the hole;
  5. Seal the hole with the clay;
  6. Drink it, using the straw.
You can't drink. At beginning this looked a bit stupid right? But now you understand.

When we use the straw we don’t really think about what happens in the plastic tube, but the straw only works because the liquid we suck is replaced with air. In fact is all about pressure.
  • When, in optimal conditions, we place a straw in a drink, the air pressure in the drink in exactly the same inside the liquid on the straw.
  • When we pull the liquid up, we remove some air from inside the straw, and the pressure inside the plastic tube drops.
  • While this is happening inside the straw the pressure on the surface of the liquid remains the same.
  • This pressure variation, between surface and straw interior, makes the liquid to be pushed through the tube.
  • If we close the flask, and prevent the air from circulating freely there is no way to create a pressure differential and therefore there isn't nothing to push the liquid into the straw!

Et voilá!
The juice will stay there, until you unseal the jar!


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