Grade 4 Science - Sound Chapter PDF

# 7 Sound ## Sources of sound - What do you remember about sound around us? - You have learnt about sound in school, about sound at home, and about sound when you are out and about where you live. - These activities will help you to remember and share with others what you know about sound. ### Ac...

# 7 Sound ## Sources of sound - What do you remember about sound around us? - You have learnt about sound in school, about sound at home, and about sound when you are out and about where you live. - These activities will help you to remember and share with others what you know about sound. ### Activity 1 - Collect five different sound sources, but do not show them to your partner. - Tell your partner to look away as you use each sound source to make a sound. - Ask your partner to guess the name of the sound sources. - How many answers did your partner get correct? ### Activity 2 - Go on a sound walk inside the school and the school grounds. - Stand still every so often and listen. Identify as many different sound sources as you can, and write them down. Try to identify ten different sound sources. - Share your sound sources with your partner. Did you identify similar or different sound sources? ## How sounds are made - **Think like a scientist!** - Sounds are made when objects vibrate. Vibrate means to move backwards and forward (or up and down) very quickly. A sound travels from its source as a vibration. - Vibrations travel through gases, liquids and solids. The vibrations travel to your ear and are heard as sounds. - Vibrations cannot always be seen, but you can often feel them. - If something makes a sound, part of it must be vibrating. - When you talk, your vocal cords vibrate. (Try putting your hand on your voice box and feel the vibrations when you talk.) - When an instrument is played, part of it vibrates. ### Experiment 1 - **You will need...** - container - tuning fork - water - Fill the container with water. - Tap the tuning fork on the table. Put it carefully on the end of your nose, then on your cheek. - What can you feel? - Tap the tuning fork on the table again. This time, place it into the container of water. - What happens? - What do you hear and what do you see? - What is causing this to happen? ### Experiment 2 - **You will need...** - ping pong ball - string or wool - tuning fork - Tape the ping pong ball to the string. Hold the end of the string so that the ball hangs down. - Tap the tuning fork on the table. Then touch it to the side of the ping pong ball. - What happens? What do you hear and what do you see? What is causing this to happen? ### Experiment 3 - **You will need...** - ruler or spatula - Put the spatula or ruler on the edge of the table so it overhangs. - Pull the spatula or ruler down and let go. - What happens? What can you hear? What can you see? ## Volume - loud and quiet sounds - **Think like a scientist!** - In the activities on page 92, you tapped a tuning fork on the table. It probably made a humming sound. You saw the water splash out of the container and the ping pong ball move because the tuning fork was vibrating. - Here are some more activities to help you understand sounds and vibrations. This time, the activities will help you understand the link between vibrations and volume (how loud a sound is). ### Experiment 4 - **You will need...** - drum - drumstick - bird seed - This is a good activity to do outside on grass. No-one will slip on the seeds and the birds can eat them when you have finished! - Put some seeds on the drum. - Tap the drum gently. What happens? Why? - How does this link to sound and vibrations? Tell your partner. ### Experiment 5 - **You will need...** - drum - drumstick - **Work in pairs.** - Ask your partner to place their hand just above the drum skin. Tap the drum with the drumstick. (Do not hit your partner's hand!) - Swap with your partner and try the activity again. Tell each other what you felt. Use the word vibrate. - Repeat a and b, but this time make a loud sound and then make a quiet sound when you tap the drum. What do you notice about what you feel when you make a loud sound and when you make a quiet sound? - Talk with your partner. What do you think the link is between the vibrations of the drum and the air above the drum? ## How sounds travel - **Think like a scientist!** - You have seen bird seeds bounce off a drum skin when you tapped it. This happens because the drum skin is vibrating. - When you hold your hand over a drum and your partner hits it, you can feel the air above the drum vibrate. - When something vibrates, the air around it vibrates. This is because, when something vibrates, it makes the air particles next to it vibrate. The air particles bump against each other, passing the vibration from one particle to the next until the vibration reaches your ear. Your brain then works out what the sound is. ### Experiment 6 - **You will need...** - balloon - balloon pump - Use an inflated balloon. Hold the balloon in your hands, with your arms straight in front of you. - Ask your partner to talk at the balloon. They must not touch the balloon with their mouth. What can you feel? - Change over and repeat the activity. - Discuss with your partner what is happening. Think about the air particles around your mouth, the material the balloon is made of, and the air inside the balloon. - Repeat the activity. This time, make a quiet sound and a loud sound. What happens to the vibrations? - Draw and annotate (label) a picture of what you did and what you found out. ### Experiment 7 - **You will need...** - plastic cup - pencil - 40 cm of string - paper clip - small piece of wet cloth - Make a small hole in the bottom of the cup with a pencil. - Thread the piece of string through the bottom of the cup. - Tie the end of the string onto a paper clip, to stop the string coming back through. - Rub the string with a damp cloth. - How is the noise made? What is vibrating? - How does the sound get to your ears? - What do you think will happen if you change the type of cloth you used to rub the string? Make a prediction. - Which other variables could you change? Choose one to change. - Make a prediction. Carry out your test to see if your prediction was correct. ## Humming - **Think like a scientist!** - You have been exploring how sounds are made. When objects vibrate, the air around them vibrates. The vibrations pass to your ear. Now you will use what you know to make percussion instruments. These instruments make sounds when you hit or shake them. - Look carefully at these drums from around the world. How do you think they are made? - Design your own drum. First draw a plan. What resources will you use? - Make your drum. Then use it to create some music. - How can you change the sound that your drum makes? What can you do to make the drum louder or softer? - Play your drum to the class. Explain how a drum makes sounds. Use the sound words that you know so far: - vibration - travel - vibrate - air - particles - sound - source - hear - ear - In groups, listen to drumming music from around the world. You might find some on the internet. Then have your own drumming session. ## Musical instruments around the world - **Think like a scientist!** - Think back to when you made percussion instruments. You found out how each instrument made its sounds. Now you will apply what you know about how sounds are made to different musical instruments. The first is a guitar. - A guitar is a string instrument. How does a guitar work? Vibrations create sounds. A guitar makes sounds when someone plucks (pulls or picks up) the strings. The strings vibrate. ### Experiment 8 - **You will need...** - box or plastic container - elastic bands of different sizes and thicknesses - Look at the pictures. Then make your own simple guitar. Explore your guitar to find the answers to these questions. - How do you make sounds on your guitar? - What vibrates? - How do you have to change the way the elastic bands vibrate to make the sound louder and quieter? - What happens to the sound when you change the thickness of the elastic bands? Is the sound higher or lower? - What happens to the sound when you make the elastic bands tighter? Is the sound higher or lower? - Draw a picture of your elastic-band guitar or, if possible, take a photograph of it. Write captions around your picture or photograph to show how to make sounds. - Keep your simple guitar as you will explore it further on the next page. ## Hanging the pitch of a sound - **Think like a scientist!** - Sounds can be loud or quiet. This is called the volume of a sound. - On page 96, when you changed the thickness of the elastic bands and how tight they were, you probably noticed that the sounds your guitar made changed. Some sounds were higher, and some sounds were lower. - When musicians change sounds to make them higher or lower, this is called changing the pitch of a sound. The pitch of a sound is how high or low it is. ### Experiment 9 - **Work with a partner to look at the guitars you made on the previous page.** - Discuss how to make the sounds on your guitars. What is vibrating? - Work together to change the sound your guitars makes. - Did you both make the same changes? - What did you do to change the volume of the sound? - What did you do to change the pitch of the sound? - Describe to each other how to change the volume and pitch of the sound your guitars make. ### Experiment 10 - **You will need...** - elastic bands of different thicknesses - recyclable materials - video camera - Class 5 learners designed and made their own guitars using recyclable materials. In the right are some of their guitars. Design and make your own elastic-band guitar. - Work out how to change the volume and pitch of the sound your guitar makes. - Play a tune, one that you already know or one that you make up. - Work with a partner to create a one-minute video of you explaining how you made the guitar and how it works, then playing a tune. Remember to use correct scientific ideas and words. - Show your video to someone else in your class. Do they think that your descriptions and explanations are correct? Why or why not? ## More about changing the pitch of a sound - **Think like a scientist!** - The length of a vibrating object influences the pitch of the sound it makes: - When an object is shorter, the material can vibrate faster than it can when the object is longer. - The faster a string (for example, on a guitar) or a ruler vibrates, the higher the pitch of the sound. - The slower a string or a ruler vibrates, the lower the pitch of the sound. ### Experiment 11 - **You will need...** - six jam jars or bottles of the same size - measuring cylinder - water - food dyes of different colours - wooden spoon - metal spoon - Working in a group, you are going to make a bottle xylophone like the one in the picture below. - Use the measuring cylinder to pour different amounts of water into each bottle, as shown in the picture below on the right. The first bottle should have the most amount of water. The last bottle should have the least amount of water. - Add different colour food dye to each bottle. - Use a wooden spoon. Gently hit each bottle in turn. - Listen to and describe the sound of each bottle to each other. How does the pitch of the sound change? - What is the pattern between the amount of water in the bottle and the pitch of the sound the bottle makes when it is hit? - What happens to the sound when you change the material of the spoon you use to hit the bottle? - Now change the amount of water in each bottle. What happens to the pitch of the sound? ## Volume and pitch in wind instruments - **Think like a scientist!** - So far, you have found out the following: - In a drum, the skin vibrates to make a sound. - In a guitar, the string vibrates to make a sound. - In a bottle xylophone, the water in the bottle vibrates to make a sound. - In a musical instrument such as a recorder, the air vibrates to make a sound. We need to make the air in some instruments vibrate to make them work. We call these wind instruments. - Look at the picture on the right. Notice that each bottle contains a different amount of water. Anna is blowing across the bottles. The water and the air are vibrating in each bottle. The amount of air in each bottle is called the column of air. When Anna blows over each bottle, the column of air vibrates and makes a sound. Different amounts of water in each bottle make the column of air longer or shorter. ### Experiment 12 - **You will need...** - glass bottles - water - Make some musical bottles. Set up your musical bottles as you can see in the picture above. Blow over them to make sounds. - Explore your musical bottles. How can you change the volume of the sounds? - What happens as you blow over the bottles? Start at the bottle with the most amount of water in it. Work through to the bottle with the least amount of water in it. - How do you change the pitch of the sounds? ## Making pan pipes - **Think like a scientist!** - You have found out the following: - Blowing over bottles makes a sound. - Blowing hard over bottles makes the sound louder. - Blowing softly over bottles makes the sound quieter. - The longer the column of air in the bottle, the lower the pitch. - The shorter the column of air in the bottle, the higher the pitch. - Pan pipes are a wind instrument. They are made from a row of pipes of different lengths. The pipes are fixed together. To play the pan pipes, you blow across the tops of the pipes, just as you did with the musical bottles. People in Peru played pan pipes 5000 years ago! Today, many people still play pan pipes. ### Experiment 13 - **You will need...** - eight straws - ruler - card - sticky tape - scissors - You are going to make your own pan pipes. - Cut your straws to these lengths: 4 cm, 6 cm, 8 cm, 10 cm, 14 cm, 16 cm, 18 cm and 20 cm. - Line up your straws from the shortest to the longest. Place sticky tape across the straws to keep them together. - On both sides of the straws, place a piece of card. This will make a pipe sandwich. - Play your pan pipes. - How can you change the volume of the sound? - What must you do to play a higher or lower sound? - Make up a tune by changing the volume and pitch. - Play your tune to someone else. Explain how you change the sounds. Use these words: - column of air - volume - air - pitch - vibrate ## Science in context - **Music around the world** - Music has been enjoyed all over the world for thousands of years. - Some of the first musical instruments were simple percussion instruments: tapping stones together or hitting hollow logs. Archaeologists have found flutes made from the tusks of mammoths, similar to the one in the picture on the right. - People all over the world use science to understand how to use different materials to make sound and how to change the volume and pitch of a sound. This scientific understanding is an important part of making and playing musical instruments. - **World instruments** - Here are some instruments from around the world. ### Activity 14 - Do some research to find out how each instrument makes its sound, and how the volume and pitch of each instrument are changed. - Research three more world instruments. Find out: - the name of the instrument - where in the world it comes from - how it makes sound - how the volume and pitch are changed. ## Musical band - **Think like a scientist!** - You have learnt how sounds are made and how to change the volume and pitch of a sound. You have also made some musical instruments. - Now you are going to work in a group and apply what you know to make a musical instrument for your group's band. You will have to decide which instrument you are going to make and play. Then, with the rest of your group, you will perform a song for your class. ### Activity 15 - In a group, discuss the instruments that your band will make and play. - Decide which instrument each of you will make. Will it be a percussion instrument (played by hitting it, like a drum), a string instrument (with strings, like a guitar) or a wind instrument (which you play by blowing on it, like pan pipes)? Make sure you have a balance of different instruments in your band. - Draw a design of your instrument. Annotate your drawing with the materials that you will need, which parts vibrate, and how you will change the volume and pitch of the sound that your instrument will make. - Make your instrument. Practise playing it. If necessary, adjust your instrument to get it to make the sounds that you want. Make sure you can change the volume and pitch of the sounds your instrument makes. - With the rest of your group, create and practise a piece of music that includes changes in volume and pitch. Perform it for the class. - Here are some instruments that you could make, or you could make one of the world instruments you have learnt about. ## That have you learnt about sound? - Look at the picture of the oud below. What vibrates to make the sound on the oud? - Write a sentence to describe how you would change the volume of the sound when playing the oud. - Write a sentence to describe how you would change the pitch of the sound when playing the oud. - If you moved away from someone playing the oud, what would happen to the sound? ## Activity 16 - Describe what would happen if you blew across the bottles below. - Which bottle would make the highest note? - Which bottle would make the lowest note? ## Activity 17 - Write a definition for each of these Scientific words from this unit: - vibration - volume - pitch - column of air - wind instrument ## That can you do? - You have been learning about sounds. You can: - describe how sounds are made. - describe what volume is. - describe what pitch is. - describe how to change the volume of a sound. - describe how to change the pitch of a sound.