Diary Entry - February

The paddles used last time are in use again. This time air resistance was demonstrated by using the paddles on a rotor to slow down a falling weight. The children wanted to investigate if the size of the paddle/vane affected how quickly the weight fell. This works well as the measured times for the weight to fall are significantly different. The most dramatic demonstration was the rotor with no vanes. This was the opportunity to introduce spreadsheets for recording and organising data. The children then use the data to produce  graphs that helped them to compare results. More able children were able to suggest patterns in the graph where the area of the vane had doubled and were able to explain why repeated testing was important . The rotors were designed to have the same diameter the area was increased by increasing the width of the vane.

The second wind tunnel is delayed as Brisbay are busy, but they are confident that it will ready to collect before the end of the month.

The use of the rotors was developed by twisting the vanes to a 45 degree angle and introducing moving air from a fan. The aim is provide evidence that moving air can turn the rotor and wind up the 200g weight.  Very quickly the children were asking what blade angle would be able to wind up the weight quickly. This was another opportunity for the children to design a fair test and use the spreadsheet to organise and evaluate data. More able children were designing their own tables. These activities are preparing children to make efficient use of wind tunnel testing.

Ken has finished the jigs and they have been tested by children.

Back to main school page