What are antibiotics?

Antibiotics are medicines that help the human body fight bacteria, either by directly killing the offending germs or by weakening them so that the body’s own immune system can fight and kill them more easily.

The most widely known antibiotic is penicillin, which is made from mold. Penicillin kills bacteria by interfering with the formation of the cell walls or cell contents of the bacteria.

Does every country have its own flag?

Every country has a national flag, including the United States. Flags date back to around 1000 B.C.E., when the Egyptians used primitive versions of flags—some were even made out of wood or metal—to identify themselves and to signal to others. Ships started using flags at sea to signal to each other and to harbors, often to let them know they had a diseased crew aboard. Flags are still used today to let sailors know what weather conditions await at sea. The military also made use of flags to rally its troops. During the ancient wars, capturing an enemy’s flag was considered an honorable seizure.

Today, the most popular use of flags is to identify and symbolize the world’s countries, which became commonplace in the 1700s. When new lands are discovered—and, for example when Mount Everest and the Moon were conquered—explorers raise their country’s flag as a sign of their being the first to set foot on these unchartered lands.

Was pond ice used as the first refrigerator?

In a way, yes. Before the invention of refrigeration machines in 1805, people cut ice from ponds in winter and stored it in an icehouse. These icehouses were pits dug into the ground and lined with wood or straw and packed with snow and ice.

They were covered with an insulated roof. Because cold air sinks, the pit remained very cold, keeping foodstuffs cold and unspoiled until the early summer months.

Why do we roll out a red carpet for special guests?

The red carpet treatment dates back to the 1930s, when a carpet of that colour led passengers to a luxurious train, the Twentieth Century Limited, which ran between New York and Chicago.

Red carpet unfolded

The Twentieth Century was the most famous in America and was totally first class with accommodation and dining car menus that were considered the height of luxury. Walking the red carpet to the train meant you were about to be treated like royalty.