Send us your questions

Some of our visitors have sent emails with interesting questions, we decided to start having a space to answer them. In this space the blog "Restless Minds" will answer all questions you send us
Send us your question for the email: Restless Minds.

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.

Monday, January 21, 2013

Grow Stalactites with a string

Mira d'Aire
a cylindrical mass of calcium carbonate hanging from the roof of a limestone cave: formed by precipitation from continually dripping water

a cylindrical mass of calcium carbonate projecting upwards from the floor of a limestone cave: formed by precipitation from continually dripping water


Let´s try to do our own stalactites and stalagmites, with water and salt.
At first sight may look simple and easy, but in fact is a lot difficult because it will depend on a lot of variables.

What we need:
    • Epsom salts,
    • water,
    • 2 identical glasses,
    • string or paper towel,
    • 2 paper-clips or weights,
    • spoon,
    • bowl or pot,
    • a good place to leave the glasses siting for a few days
    How to:
    1. Fill a glass twice with water and dump it in the pot,
    2. Add 1 Epsom table spoon;
    3. Mix;
    4. Repeat again and again until the solution is saturated;
    5. Heat the heat the pot on a stove, caution!
    6. Add more salt and keep stirring, hot water can  dissolve more salt, do not boil the water;
    7. Split the water for the 2 glasses, try to be the more exact as you can;
    8. Find the location where they will sit for the next few days...;
    9. Leave a 3 or 4 inches between the glasses;
    10. Cut a string big enough to cover the distance between the glasses and hang down to the bottom of both glass;
    11. Tie the paper clips in both string ends;
    12. Place each one on a glass;
    13. Wait, observe ad take notes.
    What happens?
    After a few days we will notice a little stalactite on the string.
    With a bit of luck you will be able to see a stalagmite too.

    The water travels through the string and the salt goes with it. While the path is vertical the salt "plays along" with water, but when the path becomes vertical, the gravity wins and the saltwater is pulled down. The water trickle and leaves the salt behind on the string. With time the salt will form a  stalactite.
    If you are lucky and wait enough time you will be able to see the stalagmite formation, under the stalactite.

    This demonstration is not so easy as it seams.
    • You need a strong and concentrate solution of salt;
    • For better results immerse the string in the solution, before you place it between the glasses.
    • If the water is dripping very fast increase the distance between the cups, that will reduce the inclination angle.
    • Do not use a wood surface, it may damage the wood.
    A step further:
    • Use different strings;
    • Use other salts;
    • Use different concentration solutions;
    • Change one thing at time;
    • Register everything
    Dicionário de Mineralogia e geologia ilustrado

    Et voilá!
    Geology in the kitchen


    No comments:

    Related Posts Plugin for WordPress, Blogger...