Two variations on watercolor pencils available are woodless pencils (just the pencil 'lead' with a paper wrapper) and water-soluble crayons (like wax crayons, but they dissolve in water). Water-soluble crayons enable you to put down more pigment (or color) faster than a watercolor pencil, as they're softer and broader.
<u>The pressure of a given amount of gas is directly proportional to its absolute temperature, provided that the volume does not change (Amontons's law)</u><u>.</u>
<u> The volume of a given amount of gas is inversely proportional to its pressure when temperature is held constant (Boyle's law).</u>
