The viscosity of a fluid is basically a measure of how sticky it is. Water has a fairly low viscosity; things like shampoo or syrup have higher viscosities. Viscosity also depends on temperature: engine oil, for instance, is much less viscous at high temperatures than it is in a cold engine in the middle of winter.
One small packet of 7 grams will produce about 500 grams of beads once they are hydrated. Soak overnight to a ratio of one packet of beads to 50 parts water. You can add more water or pour out any extra water when the beads expand. They can also be used to water potted/garden plants and flowers.
Add water to the white crystalline flakes or spheres of water beads and they absorb many times their size in the polymeric gel that forms. One pound of the water bead crystals holds about 50 gallons of water! The gel that forms swells by absorbing 30 grams of water for each gram of the water crystals. Florists also use water beads as a dirt-free way to store water and to keep cut flowers fresh for a long time.