Sound travels through different kinds of matter. Sound travels through gases, liquids and solids. 1. Hold a plastic bag of water against one of your ears. Cover your other ear with your hand. Have someone hold a ticking clock against the bag of water. Listen. 2. Keep the clock in the same place. Remove the bag of water. Listen. 3. Place a block of wood between your ear and the clock. Listen. Do you hear the clock best through the air, the water or the wood?
B. 1. Place the clock 20 cm away from your ear and listen to the ticking. 2. Have your partner hold the clock at the 20-cm mark on the meter stick. Place your ear at the end of the meter stick and listen. 3. Have your partner hold a metal rod to your ear and place the clock against the rod 20 cm away from your ear. Listen. Does sound move differently through some solids than it does through others?
C. 1. Take the plastic cups (telephone) and hold your cup to your ear while your friend talks slowly and clearly into the other cup. Keep the string tight. How does it work? What is vibrating? How do the vibrations of your friend's voice reach your ear? 2. Can a third person talk and listen if another cup with a string is attached? Take the separate cup with the string and attach it to the first line. Keep all strings tight while one friend talks into one cup and the other two friends listen. Can you hear the message of the third party? How many lines could you attach? Does each addition weaken the vibrations?
Answers & Comments
Sound travels through different kinds of matter. Sound travels through gases,
liquids and solids. 1. Hold a plastic bag of water against one of your ears. Cover
your other ear with your hand. Have someone hold a ticking
clock against the bag of water. Listen.
2. Keep the clock in the same place. Remove the bag of water. Listen.
3. Place a block of wood between your ear and the clock. Listen.
Do you hear the clock best through the air, the water or the wood?
B. 1. Place the clock 20 cm away from your ear and listen to the ticking.
2. Have your partner hold the clock at the 20-cm mark on the meter
stick. Place your ear at the end of the meter stick and listen.
3. Have your partner hold a metal rod to your ear and place the clock
against the rod 20 cm away from your ear. Listen. Does sound move
differently through some solids than it does through others?
C. 1. Take the plastic cups (telephone) and hold your cup to your ear
while your friend talks slowly and clearly into the other cup. Keep
the string tight. How does it work? What is vibrating? How do the
vibrations of your friend's voice reach your ear?
2. Can a third person talk and listen if another cup with a string is
attached? Take the separate cup with the string and attach it to
the first line. Keep all strings tight while one friend talks into
one cup and the other two friends listen. Can you hear the message
of the third party? How many lines could you attach? Does each
addition weaken the vibrations?