Is cement and concrete the same thing?
No, cement is the "glue" used to make concrete. The cement in concrete is what gives concrete its strength and durability. Concrete without cement is like bread without flour.
What is portland cement?
Portland cement is a manufactured product made in several steps. First we carefully blend limestone with shale or clay and iron to a desired chemical composition. We then grind it to a fine powder called raw meal. We feed the raw meal to a rotary kiln that is fired by coal, natural gas or another high energy fuel. The temperatures in the kiln reach about 2,800° F. At these temperatures the raw meal undergoes a chemical reaction and forms a new product called clinker. The clinker is mixed with about 5% gypsum and ground to a fine powder called portland cement.
How do I make a small batch of concrete for various jobs around the house?
A good rule of thumb for small batches of concrete is: 1 part portland cement, 2 parts sand, 3 parts gravel and just enough water to make it workable (not soupy). Be careful to protect your skin from the wet concrete as it is a strong base that will cause alkali burns. If you get a small amount on your skin, wash it off with soap and water.