Have you ever watched a waitress balance a tray on one hand?
How do you balance an object on a small point?
Cardboard from a box
Mass the shapes
Balance each geometric shape on your fingertip marking the place your finger is
Record where the point is in your Observations
Mark a line straight across each geometric shape going through the marked point
Cut each shape in two on the line
Mass each piece
Balance the spoon on your finger marking the balancing point
Balancing points of the geometric shapes
Masses of the geometric shapes
Masses of the two pieces of each shape:
Balancing point of the spoon
Is the balancing point always in the measured middle of the object? Why do you think so?
Compare the mass of the object on either side of the balancing point of the cardboard shapes.
Does mass determine the balancing point of an object?
If you could cut the spoon at the balancing point, how do you think the masses of the two pieces would compare?
Another name for this balancing point is the center of gravity. Why is this a good name for the balancing point?
My rectangle was 15 cm x 20 cm. The square was 14 cm x 14 cm. The diameter of the circle was 10 cm.
The rectangle would sort of balance when my finger was close to the center of the rectangle. It balanced the best, the flattest when my finger was in the center. The same was true for the square and the circle.
The spoon was different. The balancing point was closer to the spoon bowl than to the end of the handle. The balancing point is not always in the middle of a shape.
When I cut the cardboard shapes into two pieces, the two pieces had similar masses. The square halves were the same. The others were tenths of a gram different.
The balancing point seems to be where the mass is the same all around it. If I cut the spoon at the balancing point, I would expect the masses of the two pieces to be very close to the same.
Gravity creates weight. As the balancing point is at the place in an object where the mass and the weight will be the same on all sides, it is at the center of the gravitational pull on the object, the center of gravity.