How do vaccines work?

Your immune system is made up of cells, glands, organs, and fluids that are located throughout your body. This system’s most important job is to fight infections from viruses and bacteria.

Your immune system is like the Army. When foreign invaders attack, the Army fights back. The same thing happens in your body every day. Foreign invaders, called antigens, attack your Army (immune system). The Army sends out soldiers, called antibodies, to fight the invaders. After the attack is over and the Army has won, the soldiers disappear. The Army command center has the Intelligence Agency, or memory cells. Their job is to remember the specific invaders and call a defense against them if the invaders ever attack again. The protection the memory cells offer is called immunity.

A normal, healthy immune system is able to produce millions of these soldiers to defend against thousands of attacks a day. The immune system is so effective that people do not even notice these battles going on within their bodies.

Vaccines take advantage of this system. When you are injected with a vaccine, weakened or dead “foreign invaders” enter your body. The Army follows the same rules as if the invaders were not weakened. The Army attacks the invaders and the Intelligence Agency remembers and watches. Therefore, through vaccination, you develop immunity without suffering from the actual diseases that vaccines prevent.

Why does cutting onions make you cry?

Onions are made up of millions of tiny cells. In each of these cells, different substances can be found that make an onion an onion. Two specific substances found in a cell are enzymes and sulfur, which are kept separated by different compartments.

When you slice through an onion, the knife breaks open the cells and compartments in its path and lets the enzymes and sulfur flood out, just like breaking a dam. When these two things mix together, they interact with each other to make an acid called sulphenic acid, which is sort of like sulfuric acid.

Sulphenic acid floats up into your eyes. When the acid makes contact, your eye knows that it should not be there and begins to water. This watering, or crying, flushes out the acid. This is the same reaction your eyes have if dust gets into them.

Some ways to keep from crying is to turn on a fan blowing the acid away from you, cutting the onion under water which washes away the acid, or by wearing goggles or glasses.