Part 4

A balanced diet Your body turns the food you eat into energy. There are five main food groups, and you need to eat a different amount of food from each of them in order to stay healthy. Carbohydrates Carbohydrates are found in foods such as potatoes, pasta, bread, and rice. They are the body's main source of energy. Fruit and vegetables These foods contain many vitamins and minerals, which help your body fight infections. Different colored fruit and vegetables have different benefits. Keeping healthy Your body needs energy to keep it working well. The foods you eat and how much you move your body can affect your energy levels throughout the day. Your body is two-thirds water! That's why you should drink a lot of water every day. Protein Protein builds muscles and repairs cells. Meat, fish, eggs, beans, and lentils are good sources of protein. Some protein-rich foods, like oily fish, also help keep the heart healthy. Dairy Milk, cheese, and yogurt contain calcium, which makes bones and teeth strong. Dairy foods like these also contain protein and give you energy. Fat A small amount of fat is good for you. Sources of healthy fats include olive oil, avocados, nuts, and seeds. Feel good Your brain releases chemicals that make you feel good. More energy Your lungs and heart work harder, delivering more oxygen to the body. Socializing Exercise is a good way to have fun and spend time with friends. Better concentration Increased blood flow to the brain makes you more alert and awake. Improved sleep Exercising during the day can help you get a better night's sleep.

Sleep When you are asleep, your body has a chance to rest and your brain can sort through information collected from the day's events. Most people spend one-third of their lives sleeping! Benefits of sleep It is important to get enough sleep each night to keep you healthy. Without it, you become tired and irritable. Your body starts to slow down and you are more likely to get sick. Growth During sleep, your body releases a growth hormone. Memory Your brain logs the day's important information in your memory. Mood Good quality sleep lifts your mood. Healing Your body repairs and renews cells when you are asleep. Energy After a restful sleep, you wake up with more energy. Sleep patterns There are different stages of sleep, split into REM (rapid eye movement) and non-REM sleep. You cycle through these stages a number of times during the night. Sleep starts off deep and gets lighter as the night progresses. REM During REM sleep, your eyes move very quickly under your eyelids. This is when dreams take place. Light You move around a lot more and are easier to wake during light sleep than in deep sleep. Deep Your body grows and repairs its cells during the deepest stage of sleep. An average 6–9 year-old needs 9–12 hours of sleep a night. Try to go to sleep at the same time every day. Keep your bedroom dark and cool. Wear comfortable clothes! Avoid food and drinks containing caffeine, such as chocolate and carbonated drinks. Stop looking at screens two hours before bedtime. Tips for good sleep When it gets dark, your body realizes it is time to sleep. There are certain things you can do to help you get a good night's rest.

Emotions Emotions are what we feel when we see, do, or hear about something, and they are controlled by the brain. It is normal to feel a lot of different emotions in different situations. Fear, joy, sadness, and anger are all emotions. Happy When something good happens or we do something we enjoy, it makes us feel happy. Sad We might feel sad about big changes, such as if a good friend moves away to another city. Angry We may feel angry if someone is unkind to us or if we think something is unfair. Staying healthy Everyone feels different emotions at times, and there are many things you can do to keep your mind healthy. Poor mental health can have a negative effect on your physical health, too. Writing down how you are feeling can be a great help. Mental health As well as looking after your body, it is important to take care of your mind and how you feel. This is called mental health. The state of your mental health affects how you think, feel, and act. Scared We often feel frightened if we think something bad is about to happen. People get scared by different things. Excited Looking forward to something, such as a party or a vacation, can make us feel excited. Worried It is common to feel worried when there is a problem we don't know how to handle. Talking Sharing your worries with someone else may help you feel better. It also means they can try to support you. Friends Spending time with your friends and doing activities together can make you feel happy. Sleeping If you don't get enough sleep each night, you might become irritable and find it hard to concentrate. Hobbies Doing things you enjoy helps you relax. Hobbies include painting, music, playing sports, and reading. Exercise Daily exercise, such as walking, bike riding, and swimming, keeps your mind and body healthy. Healthy eating Certain foods, like sugar, can affect how you think, so you should eat a balanced diet with a lot of fruit and vegetables.

Body talk The way you stand, what expressions you make, and how you position your hands tell others about what you're thinking and feeling, without you having to say a word! Disgust Wrinkling your nose can show you are digusted. Closed Crossing your arms in front of your chest shows you might be feeling angry. Hand gestures People often use their hands as a way of communicating. Making various shapes with your fingers and thumbs can mean certain things. Be careful though—some signs mean different things in different societies. Showing love Many people around the world make a hand gesture in the shape of a heart to represent love. Shaking hands can be a friendly way to say hello to someone. A lot of body language happens unconsciously. Facial expressions Looking at someone's face can give you a lot of information about what they are feeling. Lifting the eyebrows, smiling, or frowning communicates different emotions. Surprise Raising your eyebrows can show you are surprised. Open Opening your arms can be welcoming, or can show you feel strongly about something. Body language Body language is how the position of your body displays your feelings to others. The way you use and move your body can show someone that you are happy, sad, angry, or afraid, even if you don't tell them. Slow down! UNDERWATER SIGNS Divers exploring the ocean make signs with their hands to communicate with each other. It's impossible for them to speak since they have a tube in their mouth to help them breathe. This diver is signaling that there is a shark approaching.

Viruses and bacteria Viruses and bacteria are tiny organisms that can make us sick. Each bacterium is made up of one cell and can live in or on the body. Viruses are much smaller and need to get inside the body's cells to be able to survive. Viruses A virus has proteins on its surface, which allow it to infect a body cell. Once inside, the virus injects its genetic material and takes over the cell. The cell makes many copies of the virus—these are then released to infect other cells. Hand washing removes bacteria and viruses from your hands! Catching a cold Many viruses can only survive for a short time outside the body. They need to hop between people as quickly as possible to spread. Here's how a cold travels around! Bacteria Bacteria can be good or bad. Many good bacteria live in the body, for example in the intestines, and help to keep it healthy. Bad bacteria, however, can cause infections and may need to be treated with medicine called antibiotics. A person infected with a cold virus coughs on their hand. They shake hands with a friend and pass on the virus. When their friend itches their nose, the virus enters their nostrils. Now infected, the friend transfers the virus onto a handrail. Someone else touches the handrail and the virus sticks to their hand. When this person eats an apple, the virus gets in their mouth and infects them, too! VACCINES A vaccine is an injection that trains the body to kill a virus. Edward Jenner, an English doctor, invented the first vaccine in 1796. It stopped people from catching a deadly virus called smallpox.

Body defenses Bacteria and viruses, called pathogens or germs, can invade the body to multiply and cause diseases. The body's immune system has many defenses, which it uses to tackle the germs. Now's our chance! Germ invasion The skin acts as an excellent barrier against infection. However, sometimes scrapes and cuts happen, which open the skin's surface. It is important to keep cuts clean, since this is when germs invade. White blood cells called phagocytes surround invading pathogens and eat them. Other defenses Your immune system is constantly protecting you from pathogens. However, there are other defenses in the body that also help protect against germs. Hair Hair acts as a barrier, which some pathogens have difficulty getting past. Tears Tears contain antibacterial substances, which kill germs that get into your eyes. Saliva It's easy to eat bacteria, but saliva contains chemicals to stop them from multiplying. Mucus Slimy mucus can trap pathogens, so they can't invade the body further. Some white blood cells patrol the body to determine if cells are the body's own or not. If not, they release chemicals to kill them. Lymphocytes are white blood cells that release antibodies. These stick to pathogens and let the phagocytes know to destroy the germs. ALLERGIES The body sometimes reacts to common substances, such as dust or pollen, as if they were pathogens. This causes an allergic reaction. Allergies are usually mild, but sometimes they can be more serious.