Task 5

Materials and tools for a working group:

• 2 pieces of smaller plastic cups (eg 2dcl), 2pcs larger plastic cups (eg 5dcl), 2 pcs of cans (eg from sterilized vegetables), 2pcs of hard plastic cups, measuring tape, scissors

Task 5 builds on the task 4. While in the previous task pupils were trying to investigate which material (string) the sound is being transmitted better, in this task they try to improve the string phone by replacing the plastic cups. Pupils perform the task in the same way as the previous one. It is important that when comparing original cups and their alternative substitutes (for example, paper cup, can, hard cup), all other conditions are kept the same. For example, in this case they must use the same length of string of the same quality on both phones that they know to transmit the sound. They will conclude the investigation. They also wonder if the cup in the phone is of any significance, just use the string.

After the investigation, the teacher encourages pupils to try to investigate when the string phone works and when not. It leads them to characterize how to use a string phone to hear each other and when they no longer hear. For inspiration, he can suggest different interventions – for example, cutting the string and rebinding it; catching string during phone calls; telephoning through closed doors, etc. The results of investigation when the sound transmission stops will be recorded on the worksheet in Task 5, based on what they found.