Magnetism is the ability of a material to be attracted by a magnet. It also include the ability for some material to act like a magnet. No doubt youve handled refrigerator magnets. You can see some in Figure 1.28. You probably know they stick to a metal refrigerator. This is what holds your homework up. Maybe your little sisters drawings are hung on the fridge in this manner. Do magnets stick to all materials? Of course not. You have probably checked and they do not stick to other surfaces. They do not stick to wooden doors or glass windows. Wood and glass are not attracted to a magnet. Obviously, only certain materials are attracted to magnets.

Question: "Can you stick your sister's drawings to a wooden cupboard with a magnet?"

Response: "NO, because They do not stick to wooden cupboard"

A: yes

You couldnt survive without your skin. It has many important functions. The main function of the skin is controlling what enters and leaves the body. It prevents the loss of too much water from the body. It also prevents bacteria and other microorganisms from entering the body. The skin helps maintain a constant body temperature. It keeps the body cool in two ways. Sweat from sweat glands in the skin evaporates to cool the body. Blood vessels in the skin dilate, or widen. This action increases blood flow to the body surface. This allows more heat to reach the surface. The heat is then able to radiate off the body. The opposite happens to retain body heat. Blood vessels in the skin constrict, or narrow. This decreases blood flow to the body surface. This reduces the amount of heat that reaches the surface. When this happens, less heat can be lost to the air.

Question: "What action do the blood vessels take to increase blood flow?"

Response: "Dilating"

A: yes

Our sun and other stars release light energy. At least this is what we see. Our Sun and stars also emit more than just light. Scientists call the type of energy that our Sun and stars release electromagnetic energy. This form of energy travels through space. Electromagnetic energy includes the light we see. It also includes much more. Many of these things we know about, but dont always think about. Electromagnetic energy includes radio waves, microwaves, and X rays. We now have devices in our homes and offices that release these same forms of energy. We use electromagnetic energy to make our lives better.

Question: "Do light and radio waves travel through space?"

Response: "Yes"

A:
yes