TAR is a black, sticky liquid like that used in road surfacing. You can't see tar in cigarette smoke but in the lungs the tiny specks join together to form a black coating. Many of the substances in tar damage the lungs, causing breathing problems and often cancer. People sometimes start smoking because they think it makes them look grown up and cool. Because you know how much it can harm your body the grown up decision is not to smoke.
Smoking is expensive.
It makes your hair, your clothes and your breath smell. Being smelly is definitely not cool. When people smoke, only some of the smoke goes into their own lungs. The rest goes into the air. Breathing in the smoke from other people's cigarettes is called passive smoking.