Plane Figures: Horizontal line - curved or straight?
- A globe
- Frame of smallest circle inset
- Knitting needle
- Invite the child to identify their hometown on the globe.
- Place the inset frame on the globe so that the town coincides with the center of the circle.
- This curve (the rim of the frame) represents the horizon for everyone living here in and around the town.
- Because we are standing outside the earth we see the entire horizon as a circle, instead of as an arc-part of the circumference.
- With the chalk mark a point on the floor.
- Draw a circle around this center point.
- Invite the child to stand at the center.
- What do you see? Without turning the child can only see an arc, a part of the circumference.
- Reinforce the facts that in these demonstrations the child is much bigger than the circle on the globe or on the floor, when in reality it is the reverse.
- The child is a tiny, tiny point in relation to the earth which is huge.
- The curvature of that arc would be so slight that you would only be able to see a straight line.
- With the knitting needle, hold it so that it forms an arc on a horizontal plane.
- Invite the child to identify what he sees as he lowers his body..... a curved line.... a curved line... a straight line.
- At eye level this curved line looks like a straight line.
Control Of Error
Points Of Interest