Chemicals Used in Daily Life

Food Preservatives: Keeping Food Fresh

What are they?
Food preservatives are substances that help food stay fresh longer and stop it from spoiling.

Types of Preservatives:

🔹 Chemical Preservatives (made in labs):

• Sodium Benzoate – used in juices and soft drinks
• Sorbate – keeps cheese and baked goods fresh
• Sulphur Dioxide – used in dried fruits
• Nitrates/Nitrites – used in meats like bacon
• BHA & BHT – keep oils and snacks from going bad

🔹 Natural Preservatives (from nature):

• Salt – used in pickles and cured meats
• Sugar – in jams and jellies
• Vinegar – for pickling vegetables
• Lemon/Lime Juice – stops fruits from browning
• Honey, Garlic, Rosemary – have natural germ-fighting powers

💡 Fun Fact: Freezing, drying, and pasteurization (heating) are also natural ways to preserve food!

Fruit Ripening Agents

Sometimes, fruits are ripened artificially so they reach the market faster.

Common Ripening Agents:

• Calcium Carbide – ⚠️ Not safe! Can be harmful if used on fruits.
• Ethylene Gas – A natural, safer gas that helps fruits ripen evenly.
• Ethephon – A chemical that releases ethylene slowly.

✅ Tip: Always wash fruits well before eating. Choose naturally ripened fruits when possible!

Chemicals Used for Cleaning

🔹 Soap

• Made by mixing oils/fats with sodium hydroxide (NaOH) – this process is called saponification.
• Works well in soft water, but forms "scum" (white residue) in hard water.

🔹 Detergent (Soapless Soap)

• Made from chemicals like sodium lauryl sulphate or alkyl benzene sulphonate.
• Works well in hard water and cleans better than soap in many cases.
• Look for biodegradable detergents—they break down easily and are kinder to the environment! 🌍

Chemical Pesticides: Protecting Crops

What are pesticides?
Chemicals used to kill pests (insects, weeds, fungi, rodents) that damage crops.

Types of Pesticides:

How Pesticides Work:

• Contact: Kills pests on touch
• Stomach: Works when pest eats the treated plant
• Systemic: Absorbed by plant; kills pests that feed on it
• Fumigants: Gas that kills pests in stored grains

⚠️ Safety Tips for Using Pesticides:

1. Wear gloves, mask, and full sleeves.
2. Never eat, drink, or smoke while spraying.
3. Store pesticides in original labeled containers, away from children.
4. Spray in the morning or evening (not in strong sun or wind).
5. Wash hands and clothes after use.
6. Follow Integrated Pest Management (IPM) – use natural methods first!

Chemical Pollution: What Happens When Chemicals Go Wrong?

When chemicals are misused, they can harm:

• 🌱 Soil and water
• 🐟 Animals and birds
• 🫁 Human health (e.g., asthma, skin problems)

Examples of Harmful Chemicals:

• DDT, BHC, Aldrin – Stay in the environment for years; can cause health issues.
• These are called persistent pollutants because they don't break down easily.

✅ What Can We Do?

• Use eco-friendly products
• Reduce, reuse, recycle
• Support organic farming
• Learn and share safe chemical practices!

Quick Recap (Test Yourself!)

1. Name two natural food preservatives.
2. Why is ethylene gas safer than calcium carbide for ripening fruits?
3. What is the main difference between soap and detergent?
4. What does "biodegradable" mean?
5. List three safety rules when using pesticides.

(Answers: 1. Salt, vinegar, lemon, etc. 2. Ethylene is natural and non-toxic; calcium carbide can contain harmful impurities. 3. Soap forms scum in hard water; detergent works in all water types. 4. Can be broken down naturally by microbes. 5. Wear protective gear, store safely, wash after use, etc.)

🌈 Remember: Chemicals are helpful when used wisely—but safety and care always come first! Ask your teacher or parents if you have questions. Stay curious and stay safe! 😊🔬