Formation of Crystals

eTwinning project «More than STEM»

Presentation and photos made by children of

Science group in Balvi Primary school

Salt crystals

• Pour hot water into the cup till half. Add 2 tablespoons of cooking salt and stir until it is dissolved.

• Pour 2 tablespoons of made solution into a dish and place it in a warm place.

• Within a few days salt crystals are formed.

Why did it happen?

• Water evaporates. Evaporation occurs more quickly in a warm room.

• Once the water has evaporated, the salt crystals remain on the plate.

Crystals on the thread of yarn

• Fill 2 glasses with warm water. Add salt and stir it. When salt begins to stay on bottom of glass, stop adding salt to water.

• Cut the thread of yarn. Put it over glass, letting thread be in salt water.

• Crystals are formed slowly. It can take up to a week until a lot of small salt crystals are formed around the thread of yarn. In addition, the glass is also "grown" with crystals.

Small Salt Crystals

• Experiment secret: only a certain amount of salt can be dissolved in a given volume of water.

• If the water is the warmer, the more salt can dissolve.

• When the water slowly cools down, an "excess" salt begins to crystallize around the yarn's thread and edges of glass.

• You can also use food coloring.

Soda (sodium bicarbonate)

• Soda is a white, powdery substance.

• It is used in food industry as a dough cleanser.

• Drinking soda is great for removing various unpleasant smells.

• With soda you can clean sinks, tiles, taps.

Crystals on the yarn

• Fill 2 glasses with hot water. Mix in 6 teaspoons of soda and stir until it is dissolved.

• Put the glasses in a warm place.• Cut the thread of yarn and put

each end in glasses. The thread must stretch, but it should not touch the dish.

Crystals of Soda

• Within 1 week crystals appear on the thread.

• The crystals of soda look very beautiful.

• The thread absorbs the solution. When the water evaporates, the crystals of soda remain over.

• Crystals on the thread are formed when the solution begins to drip and evaporate from the yarn.