1. Rust and Food Spoilage Our New Unit

2. Unit Overview In this unit, you will learn about how metals rust and how different types of food go bad. You will also learn how to stop these things from happening.

3. Vocabulary Rust (n.) – a reddish or yellowish brown coating that forms on iron or steel.

4. Vocabulary Mold (n.) – A furry growth caused by a fungus.

5. Vocabulary Spoil (v.) – to make something bad or worse; to ruin The milk spoiled after sitting on the counter for three days. I hope the rain won’t spoil our picnic.

6. Vocabulary Prevent (v.) – to stop something from happening

7. Vocabulary Preserve (v.) – to keep or save from danger. You need to preserve your food correctly so it won’t spoil.

8. What Causes Rust? Another name for rust is iron oxide (Fe2O3). Rust forms when iron or steel come into contact with air and water. The oxygen in air and water cause metals to rust.

9. What Causes Rust? Humid or damp air can cause metals to rust because of the water in the air. Salt makes metals rust more quickly and easily, so if you’re near the sea you need to be extra careful.

10. The Effects of Rust When rust happens, metals are actually changing into iron oxide. This makes the metal weaker and easier to break. Therefore, whatever rusted is not as useful as before.

11. The Effects of Rust Rust also makes a nice home for certain bacteria that are harmful to humans. Therefore is you are cut by a rusty piece of metal, you can get a serious infection.

12. How to Prevent Rust The easiest way to prevent rust is to stop air and water from coming into contact with your metal. The easiest way to do this is to paint the metal. Other coatings can be put on top of metal to prevent rust, also.

13. What Causes Food Spoilage? Many factors cause food spoilage including microorganisms, enzymes, oxygen, moisture, temperature, and light. In our class, we are going to focus on microorganisms, especially bacteria and mold.

14. What Causes Food Spoilage? Most types of bacteria are not harmful to humans, but if you eat a large amount of them, they can make you sick. Some types of bacteria are harmful to humans, and if you eat them, they will make you very sick.

15. What Causes Food Spoilage? Both bacteria and mold grow best in warm, moist conditions. They both love food, and they will both increase over time. Both mold and the bacteria that will make you sick need moisture and oxygen to live and spread.

16. The Effects of Food Spoilage When food spoils, it can become dangerous to eat. It can make people sick, and it can cause food poisoning. Food changes color and texture, and it smells and tastes bad. Food becomes less nutritious. Food is wasted. Therefore, natural resources and money are wasted.

17. How to Prevent Food Spoilage The key to preventing food spoilage is to store your food properly. Store appropriate foods in the refrigerator or freezer, and make sure your refrigerator is set at 4 degrees C or lower. Store food in its own container, and remove as much air as possible from the container. If you notice food that has spoiled, get rid of it right away.

18. Quiz Next Week! Be sure you know the vocabulary. Know the causes, effects, and ways to prevent rust and food spoilage.