Science experiments for children – Ice cube necklace
What do you need?
ice cubes,
a glass of water,
a cotton thread,
salt.
Science experiments for children – Ice cube necklace
What to do?
Put some ice cubes in a glass of water. Wet cotton yarn, then lay him on cubes floating in the glass. Sprinkle salt over the entire length of the thread and waits about 10 seconds. Raises the thread: you will in your hands your necklace of ice …
Science experiments for children – Ice cube necklace
What happens?
Pure water freezes at 0 ° C. The addition of salt or of any other substance soluble (eg sugar), it reduces the freezing temperature of water. The sea water for example freezes at -1.8 ° C, but continuing to add salt to its freezing temperature can reach up to -21 °
This occurs because the solutes disrupt the crystalline structure of ice and reduces the concentration of pure water. Any reduction in the concentration of pure water lowers the freezing point. Therefore the higher the salt concentration, the lower the freezing point.
When it is sprinkled with salt an ice cube, at that point the salt concentration becomes high, the freezing point goes down much and the portion of the ice enters into contact with the salt melts and flows along the cube residue, bringing with them the salt. At this point on top of the cube water, less salty, refreeze, trapping the cotton thread.
Links
http://littleworldsbigadventures.com/summer-activity-making-ice-cube-necklace/
http://www.sundownersdaycare.com/youth-club/ice-cube-necklace/
http://www.education.com/activity/article/Ice_Cube_Necklace_preschool/
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