Sound

Question 1

What the equipment utilised for the practical investigating the Speed of sound?

Answer 1

Trundle Wheel, wooden blocks, stopwatch, oscilloscope, 2 microphones and a tape measure.

Question 2

What is the purpose of trundle wheel in the practical investigating the speed of sound?

Answer 2

To measure the distance travelled by the sound waves.

Question 3

What is the purpose of wooden blocks in the practical investigating the speed of sound?

Answer 3

To create a sound by banging together.

Question 4

What is the purpose of the stopwatch in the practical investigating the speed of sound?

Answer 4

To time how long it takes the sound waves to travel.

Question 5

What is the purpose of the oscilloscope in the practical investigating the speed of sound?

Answer 5

To display the sound wave electronically.

Question 6

What is the purpose of the two microphones in the practical investigating the speed of sound?

Answer 6

To detect sound waves and turn them into an electric signal.

Question 7

What is the purpose of the tape measure in the practical investigating the speed of sound?

Answer 7

To measure the distance between microphones.

Question 8

What are the two experiment to investigate the speed of sound?

Answer 8

Experiment 1: Measuring the Speed of Sound Between Two Points with a stopwatch

Experiment 2: Measuring the Speed of Sound with Oscilloscopes

Question 9

What is the aim of the experiment: Measuring the Speed of Sound Between Two Points (with a stopwatch)?

Answer 9

The aim of this experiment is to measure the speed of sound in air between two points.

Question 10

What is the independent variable of the experiment: measuring the speed of sound between two points (with a stopwatch)?

Answer 10

Independent variable = Distance

Question 11

What is the dependent variable of the experiment: measuring the speed of sound between two points (with a stopwatch)?

Answer 11

Dependent variable = Time

Question 12

What is the control variable of the experiment: measuring the speed of sound between two points (with a stopwatch)?

Answer 12

Control variables:
Same location to carry out the experiment

Question 13

What is the method for the experiment: measuring the speed of sound between two points? (using a stopwatch)

Answer 13

1. Use the trundle wheel to measure a distance of 100 m between two people
2. One of the people should have two wooden blocks, which they will bang together above their head to generate sound waves
3. The second person should have a stopwatch which they start when they see the first person banging the blocks together and stop when they hear the sound
4. This should be repeated severa times and an averade taken for the time travelled ov the sound
   waves
5. Repeat this experiment for various distances
6. Make a table of results

Question 14

What is the equation for average speed?

Answer 14

Average speed = Distance moved/Time Take

Question 15

What is the speed of sound in air?

Answer 15

The speed of sound in air should work out to be about 340 m/a.

Question 16

What is the aim of the experiment: measuring the speed of sound with oscilloscopes?

Answer 16

The aim of this experiment is to measure the speed of sound in air between two points using an oscilloscope.

Question 17

What is the independent variable for the experiment: measuring the speed of sound with oscilloscope?

Answer 17

Independent variable = Distance

Question 18

What is the depedent variable for the experiment: measuring the speed of sound with oscilloscopes?

Answer 18

Dependent variable = Time

Question 19

What are the control variables for the experiment: measuring the speed of sound with oscilloscopes?

Answer 19

Control variables:
- Same location to carry out the experiment
- Same set of microphones for each trial

Question 20

Describe the method for the experiment to measure the speed of sound with oscilloscopes

Answer 20

1. Connect two microphones to an oscilloscope
2. Place them about 2 m apart using a tape measure to measure the distance between them
3. Set up the oscilloscope so that it triggers when the first microphone detects a sound, and adjust the time base so that the sound arriving at both microphones can be seen on the screen
4. Make a large clap using the two wooden blocks next to the first microphone
5. Use the oscilloscope to determine the time at which the clap reaches each microphone and the time difference between them
6. Repeat this experiment for several distances
7. Make a table of results

Question 21

What is the systematic error in the experiment: measuring the speed of sound with oscilloscopes and what is the solution?

Answer 21

The scale is likely to be small (e.g. milliseconds) so ensure this is taken into account when calculating speed. Solution: Ensure the scale of the time base is accounted for correctly

Question 22

What is the random error in the experiment: measuring the sound of speed between two points (with an oscilloscope) and what are the solutions?

Answer 22

A main cause of error in Experiment 1 is the measurement of time
Ensure to take repeat readings when timing intervals and calculate an average to keep this error to a minimum
Maximise the distance between the two people where possible. This will reduce the error in measurements of time because the time taken by the sound waves to travel will be greater

Question 23

What is an oscilloscope?

Answer 23

An oscilloscope is a device that can be used to study a rapidly changing signal, such as: a sound wave and an alternating current

Question 24

What is the time base (the ‘x-axis’) is used to measure on an oscilloscope?

Answer 24

The time base (the ‘x-axis’) is used to measure the time period of the wave

Question 25

What is the height of the wave on an oscilloscope related to?

Answer 25

The height of the wave is related to the amplitude of the sound.

Question 26

What is the aim of the experiment: using an oscilloscope and a tuning fork?

Answer 26

The aim of this experiment is to investigate the frequency of a sound wave using an oscilloscope.

Question 27

What is the independent variable in the experiment: using an oscilloscope and a tuning fork?

Answer 27

Independent variable = Tuning forks of different frequencies.

Question 28

What is the dependent variable in the experiment: using an oscilloscope and a tuning fork?

Answer 28

Dependent variable = Time period.

Question 29

What are the equipment used in the experiment: using an oscilloscope and a tuning fork?

Answer 29

5 tuning forks, microphones, oscilloscope and wires.

Question 30

What is the purpose of the 5 tuning forks used in the experiment: using an oscilloscope and a tuning fork?

Answer 30

To generate sound waves of different frequencies.

Question 31

What is the purpose of the microphone used in the experiment: using an oscilloscope and a tuning fork?

Answer 31

To detect sound waves from the tuning fork

Question 32

What is the purpose of the oscilloscope used in the experiment: using an oscilloscope and a tuning fork?

Answer 32

To display the sound waves electronically.

Question 33

What is the purpose of the wires used in the experiment: using an oscilloscope and a tuning fork?

Answer 33

To connect the microphone to the oscilloscope

Question 34

What is the method for the experiment: using an oscilloscope and a tuning fork?

Answer 34

1. Connect the microphone to the oscilloscope as shown in the image above 2. Test the microphone displays a signal by humming 3. Adjust the time base of the oscilloscope until the signal fits on the screen - ensure that multiple complete waves can be seen 4. Strike the tuning fork on the edge of a hard surface to generate sound waves of a pure frequency 5. Hold the tuning fork near to the microphone and observe the sound wave on the oscilloscope screen 6. Freeze the image on the oscilloscope screen, or take a picture of it 7. Measure and record the time period of the wave signal on the screen by counting the number of divisions for one complete wave cycle 8. Repeat steps 4-6 for a variety of tuning forks 9. Make a table of results

Question 35

What is the systematic error in the experiment: using an oscilloscope and a tuning fork and what is the solution?

Answer 35

The scale is likely to be small (e.g. milliseconds) so ensure this is taken into account when calculating the time period. Solution: Ensure the scale of the time base is accounted for correctly.

Question 36

What is the random error in the experiment: using an oscilloscope and a tuning fork and what is the solution?

Answer 36

A cause of random error in this experiment is noise in the environment Solution: Ensure it is carried out in a quiet location

Question 37

What is the pitch of sound waves related to?

Answer 37

The pitch of a sound is related to the frequency of the vibrating source of sound waves.

Question 38

What does it mean if the frequency of vibration is high?

Answer 38

If the frequency of vibration is high, the sound wave has a high pitch.

Question 39

What does it mean if the frequency of vibration is low?

Answer 39

If the frequency of vibration is low, the sound wave has a low pitch.

Question 40

What does the loudness of a sound is relate to?

Answer 40

The loudness of a sound is related to the amplitude of the vibrating source of sound waves.

Question 41

What does it mean if a sound is loud?

Answer 41

If the sound is loud, the sound wave has a large amplitude

Question 42

What does it mean if a sound is quiet?

Answer 42

If the sound is loud, the sound wave has a small amplitude.

Question 43

What is the frequency range for human hearing?

Answer 43

The frequency range for human hearing is 20 Hz to 20 000 Hz

Question 44

What is sound below 20 Hz known as?

Answer 44

Sound below 20 Hz is known as infrared

Question 45

What is sound above 20,000 Hz known as?

Answer 45

Sound above 20,000 Hz is known as ultraviolet.

Question 46

What state of matter will sound travel the fastest in?

Answer 46

Sound will travel fastest in a solid, as the particles are closest together. Sound waves must be transmitted through vibrations of particles within a medium.

Question 47

What state of matter will sound travel the slowest in?

Answer 47

Sound will travel slowest in a gas, as the particles are the most further apart together. Sound waves must be transmitted through vibrations of particles within a medium..

Question 48

What happens when sound gets reflected off a surface?

Answer 48

When sound gets reflected off a surface, it generates an echo.