Linda Hamel, age 10, of Okotoks, Alberta, Canada for her question:

What is potash?

You night suspect that this chemical comes from ashes cooked in a pot, and there was a time when this was so. The pioneers who crossed the continent in their covered wagons needed potash to wash and do their laundry. They made it in pots from the ashes of their campfires.

Potash is a crisp white chemical. We usually do not see it in everyday life, but it does a great many necessary jobs for us behind the scenes. Plants need potash to thrive and grow, and farmers use it to fertilize their soils. It is used in industry to make glass, soap and a long list of other useful items. The crispy white chemical was used to make glass and soap by our ancestors long ago.

It got its name because of the way it was made in ancient times. The first step was a blazing wood fire, enjoyed by all and perhaps used to cook the dinner. The next step is called leaching, and it began after the flaming fire had died. The ashes of the wood were gathered together and trickles of water were poured through them again and again, dissolving and carrying away certain chemicals from the ashes. It became a solution of chemicals.

The solution was boiled and boiled in a pot until all the liquid had steamed away. The dregs from the ash solution in the pot were crusty white crystals. It seemed natural to call this chemical potash. The potash was boiled with fat, often with the greasy fat from cooked meat. Of all things, these two ingredients turned into soap, our great-grandmothers often used this recipe to cook up a batch of homemade soap.

To make glass, potash is mixed with sand and metal and heated on an extremely hot furnace. The world needs countless tons of potash, and there is not time to leach it from wood ashes, so most of it is taken from ores. That contains the chemical element potassium. Potash is a chemical compound, and potassium is its main ingredient. There are several varieties of potash, and all of them are compounds of the element potassium. The molecules of the most common form of potash are made from atoms of potassium, oxygen and calcium. Its chemical name is potassium carbonate.

Potassium is a strange element, and in nature we never find it in its pure form. It is too eager to unite with other elements and form compounds, such as potassium carbonate. As a pure element it is a silvery white metal soft enough to be cut like cheese. When placed in water, it reacts with fizz and flaming fury. In the violent uproar it grabs atoms of oxygen and hydrogen from the water to form the chemical compound called caustic potash, which is potassium hydroxide.