Most commercial skeins today are made to be pulled from the center, and they don't need unwinding. If you want to roll the yarn into balls, the old fashioned way is the only way I know of, simply start at the end and lift up on the yarn. Roll it up as it comes off the skein, and then pull more off. It is a very time consuming process. You have to use some care to prevent the yarn from getting too twisted. I usually just let the skein bounce around loose on my lap, or on a clean cloth on the table.
A skein of wool can come in different weights. There is not a specific amount of wool needed in a skein.
The weight of a skein of wool can vary depending on the type and brand. Typically, a skein of wool can weigh between 50 to 200 grams. It's best to check the label on the skein for the exact weight.
Skein is a non-standard length of spun fibre, which can be wool or any other fibre.
A bale of wool. Or a skein of wool.
Skein
Yes, you change wool -- unless you find avariegated wool skein or set of them, that offer you the colours that you want.
A bale of wool
hank
A group of wool is typically referred to as a skein or a ball of wool, depending on its form. A skein is a length of yarn wound in a loose loop, while a ball is yarn wound into a round shape.
The term 240 gr indicates the total weight of the skein of wool.
A small amount of wool yarn is typically referred to as a hank rather than a skein. A hank is a looped bundle of yarn that needs to be wound into a ball before use. A skein is a different form of yarn packaging and usually contains a larger quantity of yarn.
Wool, Yarn or thread :)