In science this week, we explored electrical resistance. Our learning question was ‘Does the length of the wire affect the brightness of the bulb?’ Most of us thought that the length of the wire wouldn’t affect the brightness of the bulb and many children were able to explain their reasoning. Others thought that the length of the wire would affect the brightness of the bulb – some thought longer wires would make the bulb brighter, others thought the bulb would be dimmer.
To determine the brightness of the bulb, we used a light sensor app. We set up a simple circuit and then added additional lengths of wire into the circuit. We tried 1m right up to 12m of wire and then, for our final two tests, we tried 20m and finally 50m!
We plotted our results on a line graph; we noticed some data points were higher or lower than expected. We learnt that these are called outliers. Some children suggested reasons for these outliers – we think our data may have been affected by the light through the classroom windows (it was a cloudy day but sometimes there were breaks in the clouds and the room got brighter).
Many of us were surprised to fine that the longer the wire the dimmer the bulb. We learnt that this was due to the electrical resistance.