1.1 (k)
Contents
Demonstration 1
Finding the centre of gravity of a human. First of all, weigh the human child, then they should lie on the plank of wood, of which one end is resting on the scales; their task is to find out, by taking appropriate measurements, where the centre of gravity is.
Resources
Analysis
Anticlockwise moments = clockwise moments, the pupils should draw a diagram, label the forces and distances, they should also take into accound the weight of the plank.
Equipment
1x scales & 1x plank of wood
Safety
The plank of wood will be very heavy.
Demonstration 2
Finding an equation that allows you to calcualte the upthrust that must be supplied by a support on a bridge. Using the plank of wood, which is now balanced on two scales, one at either end. Pupils move along the plank taking measurements of upthrust. This can be extended by making the scales closer to the centre of the plank.
Resources
Analysis
Anticlockwise moments = clockwise moments, the pupils should draw a diagram, label the forces and distances, they should also take into accound the weight of the plank.
Equipment
2x scales & 1x plank of wood
Safety
The plank of wood will be very heavy.
