Drugs, alcohol and smoking · Grade 6
A drug is any substance that changes the way the body works. Medicines are drugs that treat illness. Other drugs, such as caffeine, nicotine and alcohol, are taken for how they make people feel, and they can harm the body, especially when used often.
Key facts
- Medicines (paracetamol, antibiotics, insulin) treat illness or ease symptoms. Take them only as the label or a doctor says.
- Recreational drugs: some are legal (caffeine; alcohol and tobacco for adults) and others are illegal (cannabis, cocaine, heroin).
- Stimulants speed up the nervous system (caffeine, nicotine, cocaine); depressants slow it down (alcohol, solvents, heroin).
- Many drugs are addictive: people feel they cannot manage without them and get withdrawal symptoms if they stop.
- Cigarette smoke: tar coats the lungs, damages the cilia and can cause lung cancer; carbon monoxide reduces the oxygen the blood carries; nicotine is addictive and raises the heart rate.
- Alcohol slows reactions and affects judgement; over many years heavy drinking damages the liver and brain. Smoking and alcohol in pregnancy harm the baby.
Worked examples
Example 1
A student’s reaction times were 0.26 s, 0.25 s and 0.27 s, and then 0.22 s, 0.21 s and 0.23 s after a drink with caffeine. Find each mean and say what caffeine does.
Answer: before 0.26 s, after 0.22 s: caffeine is a stimulant, so reactions got faster