This screen provides a simple test to reinforce the results of the experiment, and enables discussion of conclusions to be drawn from them.
The screen reproduces the correct experimental design and tests understanding of the concept that, 'The greater the quantity of water in the jar, the lower the pitch of the sound produced.'
Ask the children to try to account for the results, giving credit for their ideas. You may wish to explain that: as the volume of water in the jar increases, the object vibrates more slowly. This lower frequency of vibration produces a lower pitch of sound. In contrast, less water enables the jar to vibrate more quickly, and with a higher frequency the sound is a higher pitch.
If required, you can check this audibly before selecting the answers by clicking on the jars.
Common misconception: If you were to blow across bottles containing water of different levels, the opposite result emerges – the bottle with the smallest volume of water will produce the lowest pitch note, whilst the pitch becomes higher as the water level increases. As children may have seen/done this (and it would be great if they could do so!), confusion may arise. When a bottle is tapped, the bottle and water vibrate to create the sound, as considered in the simulation (the longer the column of water vibrating, the lower the pitch produced). When blowing across the top of a bottle, it is the air contained within the bottle that vibrates to create the sound wave – the longer the column of air vibrating, the lower the pitch produced. This is the same principle that occurs in all woodwind instruments.