General common students’ difficulties identified by Science Education Research around Sound are:
- Sounds can be produced without using any material objects.
- Hitting an object harder changes the pitch of the sound produced.
- Loudness and pitch of sounds are the same things.
- The pitch of a tuning fork will change as it "slows down", (i.e. "runs" out of energy)
- Frequency is connected to loudness for all amplitudes.
- Human voice sounds are produced by a large number of vocal cords that all produce different sounds.
- Sounds can travel through empty space (a vacuum).
- Sounds cannot travel through liquids and solids.
- Sound moves faster in air than in solids (air is "thinner" and forms less of a barrier).
- Sound moves between particles of matter (in empty space) rather than matter.
- You can see and hear a distinct event at the same moment.
- Music is strictly an art form; it has nothing to do with science.
- In wind instruments, the instrument itself vibrates (not the internal air column).
- Sound waves are transverse waves (like water and light waves).
- Waves transport matter.
- Waves do not have energy.
- All waves travel the same way.
- Big waves travel faster than small waves in the same medium.
- When waves interact with a solid surface, the waves are destroyed.
- Ultrasounds are extremely loud sounds.
- Noise pollution is annoying, but it is essentially harmless.
- Sounds made by vehicles (like the whistle of a train) change as the vehicles move past the listener because something (like the train engineer) purposely changes the pitch of the sound.
- In actual telephones, sounds (rather than electrical impulses) are carried through the wires.
Students have to apply their knowledge in new situations and this might reveal misconceptions. The teacher should be aware of this, with asking questions to the student the teacher can make the student reflect on their pre-knowledge.
By giving answers or presenting data the students can work with, the character of the activity can become more closed. For example, without the graph or the demo on YouTube, the activity about harmonics in the subunit 2 is bounded inquiry. The question asked is ‘in what ways might a string vibrate?’ and the students have to find their own way to answer this question. If students have enough prior knowledge and endurance, they are able to come up with the preferred answers. If not, the teacher has to decide how much he wants to help them (by doing a demo, presenting the graph or showing the YouTube movie).
An unpredictable variety of alternative or even misconceptions in the understanding of the content of the Human speech subunit is to be anticipated, as speech is such an everyday phenomenon that probably everyone has created his own model or mental picture of it. Special attention has to be devoted to common frequently felt obscurities like:
- How can it be that the same vowel pronounced by different persons may sound completely different, yet one is able to recognise the vowel as such immediately?
- What are formants and in what way do they differ by age and gender?
- Is the recorded spectral sound-pattern reproducible and recognizable?
It is here that the IBSE approach comes into play to provide a more tangible picture of the phenomenon of speech to the students. One may expect that the understanding achieved by own discoveries is less superficial and more concrete, as it is more linked to reality.