It's sand that is afraid of water!! Incredible!! You may
have seen sand sold in toy stores called 'Magic Sand' and when you put
it into water it never gets wet! Well here is a
funand
easy science activity that show you how to make you own Hydrophobic Sand
(Magic Sand).
You will need:
safetyglasses,
sand (colored crafting sand works really good), metal cake pan, oven,
water proofing spray (Scotch Guard).
Now try this:
Spread a cup of sand onto a metal cake pan, making an even layer of
sand.
Place the sand into the oven set at200degrees
for 1 hour to remove any moisture still contained in the sand.
Allow the sand tocoolcompletely
to room temperature.
With safety glasses and the assistance of an adult,
spray the sand with an even coat of water proofing spray. Make sure
your work area is covered with old newspaper or some protective
covering to protect surfaces of over spray.
Allow any volatile gases to evaporate off the sand by
shaking the sand occasionally for 10-15 minutes. Allow to dry
completely (approximately one hour) You've made your own Hydrophobic
Sand!
Slowly pour the Hydrophobic Sand into water and
observe it's behavior!
Explanation:
Hydrophobic sand is sand that repels water, there are many common
materials in our world that are hydrophobic. Oils, fats, greasy
materials, many leaves on trees are all hydrophobic and are near
impossible to wet. Their molecular structure resists attraction to the
water molecule.
Chemists have been able to utilize the behaviors of hydrophobic
molecules to make synthetic hydrophobic compounds that we find in water
proofing sprays. These sprays are used to water proof our outdoor wear
such as boots or coats. They're also put onto our carpets and upholstery
to make spills easier to clean up. Normally these materials (boots,
coats, carpets, upholstery, and in this activity sand) have an
attraction to water (this is known as being hydrophilic). The spray
coats these materials with hydrophobic molecules making that barrier
between water.
