This classic spices experiment will only take a few seconds to do and you almost certainly already have everything you need. Let's go!
Adhesives make objects cohere (or adhere) together. Cohesion is the word for this sticking force. Cohesion occurs on lots of everyday objects – rain to car windows, chewing gum on the carpet, dirt to you when you have been in the garden. This experiment demonstrates cohesion (and does not leave a mess like the chewing gum!)
Notice how the effect only occurs in the middle of the water.
The spice stays scattered all about the water because the water is pulling on the spice evenly from all directions. When you drop the detergent into the water, it reduces the cohesiveness between the water and the spice. In other words, it reduces the pulling action on the spice and the spice appears to run away from the detergent. But the water around the edges (untouched by the detergent) still has its full pulling strength.
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