CHILDHOOD CANCERS: The most common form of cancer in children is childhood acute lymphocytic leukemia, or ALL. Lymphocytes, a type of cell that helps fight infection, develops in bone marrow. If the lymphocytes grow too quickly and do not fully mature, the child has ALL. It can cause anemia, easy bruising or bleeding and swollen lymph nodes. Doctors use a blood test to count the numbers of different types of blood cells -- too many white blood cells can indicate leukemia.
A RARE DISEASE: In the United States in 2007, approximately 10,000 children under age 15 were diagnosed with cancer. But cancer is still relatively rare in this age group with, on average, one to two children developing the disease each year for every 10,000 children in the United States.
WHAT MAKES MATERIALS MAGNETIC? Magnetism is the result of the constant movement of charged electrons in atoms. As electrons swirl around an atom, they create an electrical current, and whenever electricity moves in a current, a magnetic field is created. So magnetism is a force between electric currents: two currents flowing in the same direction attract each other, while those pulling in opposite directions repel each other. The reason some materials are magnetic, while others are not, has to do with how the electrons are arranged. A magnet is an object made of magnetic materials; naturally occurring magnets are known as lodestones. Every magnet has at least one north pole and one south pole. In fact, if you take a bar magnet and break it into two pieces, each of the smaller pieces will still have a north and south pole. The Earth itself is a giant magnet with a north and south pole, which is why a magnetic compass's needle always points north/south.
The American Physical Society contributed to the information contained in the TV portion of this report.