Activities





		Owl And Mouse Echolocation Activity Noise, Sound Or Music? Banging: Let Us Make A Drum Rattling Blowing Key Wane Whistle A Humming Top Plucking A Bull Roarer OWL AND MOUSE ECHOLOCATION ACTIVITYOWL AND MOUSE ECHOLOCATION ACTIVITY This activity shows the process of echolocation that is used by some nocturnal and underwater predators, such as bats, owls and dolphins. Because the light is very dim when these animals do their hunting, they rely on sounds to find their prey. Materials: 2 clickers Directions: Have students stand in a circle holding hands. This circle will set the boundaries for the activity. Choose two students to stand in the middle of the circle. One student will have the role of the Owl (the predator) and the other will have the role of the Mouse (the prey). Put a blindfold on the Owl. Give both the Mouse and the Owl a clicker. Start by having the Owl click once. Whenever the Mouse hears the sound, s/he must click back. The Owl tries to determine the location of the Mouse and walks in that direction. The Mouse can also walk away from the Owl to avoid being "caught". The Owl clicks again, the mouse clicks in return, and the Owl again moves in the direction of the sound. Sometimes the Owl will bump into the students forming the circle. If this happens, the students should stay quiet and gently tap the Owl away from the edge of the circle. Continue until the Owl finds or "captures" the Mouse. When the Owl has touched the Mouse, the Mouse should squeak loudly so that the Owl knows that it has caught its prey. of sound by measuring how long it took the sound, made by the banging of two blocks of wood together, to cross a playing field. When a bat is searching for food, it emits very high pitched sounds that are too high for human ears to hear. This sound echoes off surrounding objects (including moths, insects, and other bat food) and bounces back towards the bat. The bat can distinguish different shapes by the echoes, so it can tell the difference between a leaf or a moth. The bat can them locate the position of its food by the echoes it receives. Return NOISE, SOUND OR MUSIC? Children seem to delight in making noises. At first almost any noise will do, then come attempts at rhythm and musical notes. Fortunately there are a number of simple musical instruments which can be made by children using everyday materials. Sounds are usually caused by something vibrating which in turn causes the air to vibrate. However, sound will travel through substances other than air, and children have rung bells under water and sent messages along pipes. They have also tried to measure the velocity of sound by measuring how long it took the sound, made by A xylophone is made of wooden bars of varying lengths laid across supports, as shown in the figure to the right. Another possibility is to drive a series of large nails of varying depths into a block of wood. Is it better to lay the block flat, or to stand it on its edge? In carrying out an investigation like this when something or some action needs duplicating or repeating a number of times, it might be best to encourage different children or groups to do the repeats and then compare their findings. Jam jars or milk bottles containing different amounts of water give different notes when struck. Which gives the highest note? Which gives the lowest note? Is it the glass or the water which gives the note? Start with an empty jar. Return BANGING: LET US MAKE A DRUM How many ways can children devise to make a drum? The hollow part can be a jar, an old saucepan, a wooden box, a tin: all shapes and sizes can be tried and different sounds produced. But it is the covering material over the open end which may give the most trouble. On a real drum it is usually parchment, which is made from skin stretched tight, and it is this tightness which is important. Materials which have been used and might be tried are: thin cotton or nylon cloth, thick wallpaper, plastic film such as polythene wrapping material, rubber sheeting. The cotton, nylon and wallpaper must be dampened and stretched tight, tied in place with string and allowed to dry, then varnished with sealant. If small seeds (radish, mustard) are sprinkled on the drum, and the drum is then tapped, the vibration of the skin can be seen. Return RATTLING The maraca used in jazz, swing and Latin music bands is a rattle made from a dried gourd and containing seeds, beads or shot. The gourd can be replaced by a squeeze bottle or two yogurt cartons taped together and a variety of rattling material can be tried (big beans, little beans, dried peas, sand, lentils). Return BLOWING Basically there are two methods of producing a note by blowing: one is to make air vibrate (e.g. by blowing across the top of a tube or bottle), the second is to make something else vibrate. An example of this is the reed in some wind instruments which can be copied using a drinking straw. Various lengths of straws give different notes, but can you make different notes without altering the length of the straw? Obtain a number of medicine bottles of the same size. Pour different amounts of water in each bottle and blow across the tops of them. Which bottle produces the highest note? Which produces the lowest note? Compare the amounts of water in each bottle. Does the one with the least amount of water give the highest or lowest note? Compare the results of this investigation with that of jam jars and water- how can the results be explained? (In the case of the jam jars, it is the glass above the water level which vibrates. The larger the amount of glass the lower the note. With the medicine bottles it is the air which vibrates. The more air there is, the lower the note.) Return KEY WANE Get a packet of straws and make a point on the end of one. Then blow into the straw. A long straw produces a low note, but if you cut a portion of the straw off a higher note is produced. Try to make a scale. The small straws make high notes and the long straws make low notes. Return WHISTLE Some whistles have a pea in them. Do they work if the pea is removed? Return A HUMMING TOP A humming top is a good way to investigate. What makes it spin? Why does it hum? Can the humming be controlled? How long will the top continue to spin? Return PLUCKING A banjo or guitar could be used to discover the change in note when the length and tension of string are varied. A number of home-made stringed instruments can be constructed. Bowing a stringed instrument is another way of inducing the strings to vibrate. The frequency of a note given by a string is increased as the length of the string is decreased. The frequency increases as the tension increases. Return A BULL ROARER Children may have heard the wind whistling through the telephone wires. This can be imitated by a primitive aboriginal instrument called a bull roarer. If this is swung around the head faster and faster, a loud humming is produced. Return