To further develop Year 6's understanding of electricity and circuits, the children had another practical lesson this term. The objective was to construct a burglar alarm!
Before doing so, the children learnt what a burglar alarm is and how modern alarms that are used in our buildings work. Burglar alarms require a disturbance of an infrared light (which is not visible to the human eye), which will then trigger the alarm to sound.
While we did not have infrared light at hand for the children (much to their dismay), we explained that a working burglar alarm could still be made by constructing a switch and attaching a protected item (fake coins from the Maths area) to it. If the protected item was taken, the switch would close, thereby allowing voltage to flow across the whole circuit completely and enabling the buzzer to sound off.
By constructing an open circuit alarm, the children's burglar alarm would only produce noise when the item was taken.
The children really enjoyed this practical lesson and it was a prime opportunity for them to explore how devices that protect them, such as burglar alarms and fire alarms, work. Additionally, it was a prime opportunity for the children to explore the significance of a closed switch in a circuit - specifically because they were able to make their own (using aluminium foil, a peg and some cardboard).
