rotation

Everyday

1. Rotation is turning around a centre point or a line: "the rotation of the Earth". tree →
2. A rotation is one complete turn: "the wheel makes 10 rotations a minute". tree →
3. In maths, a rotation is a turn of a shape around a fixed point by an angle, such as a quarter turn (90 degrees). tree →
4. Rotation is taking turns in a fixed order: "we do the jobs in rotation". tree →
5. Crop rotation is growing different crops in a field each year to keep the soil healthy. tree →

In the lessons

In maths, rotations are given by an angle (90, 180, 270 or 360 degrees), a direction (clockwise or anticlockwise) and a centre of rotation; rotational symmetry means a shape looks the same after part of a turn. In science, the Earth's rotation on its axis makes day and night, taking about 24 hours. In PE and school jobs, things done in rotation are shared fairly. Phrases: rotation of the Earth, in rotation, quarter rotation, rotational symmetry, crop rotation.

Examples

• The rotation of the Earth gives us day and night. tree →
• One full rotation of the Earth takes about 24 hours. tree →
• Rotate the triangle 90 degrees clockwise about point A. tree →
• A full rotation is 360 degrees; a half rotation is 180 degrees. tree →
• The wheel made 50 rotations in a minute. tree →
• We take the class jobs in rotation. tree →
• Farmers use crop rotation to keep the soil rich. tree →

Note

Verb: rotate. Do not mix up rotation (spinning on its own axis: Earth, one day) and revolution or orbit (going around something else: the Earth around the Sun, one year). In maths, a rotation keeps the shape's size and form; only its direction changes. Anticlockwise (UK) = counterclockwise (USA).

In Jewish tradition

Interpretation: The turning of the letters in the "gates" is read by tradition as the way they combine to make all things. In the primary lessons: In maths, rotations are given by an angle (90, 180, 270 or 360 degrees), a direction (clockwise or anticlockwise) and a centre of rotation; rotational symmetry means a shape looks the same after part of a turn. In science, the Earth's rotation on its axis makes day and night, taking about 24 hours. In PE and school jobs, things done in rotation are shared fairly. Phrases: rotation of the Earth, in rotation, quarter rotation, rotational symmetry, crop rotation.

Examples

• Rotation; from חָלֹל to dance round. (Sefer Yetzirah, Kalisch 1877) tree →
• Just as the sphere remains the same during the rotation on its axis in its setting and in its rising; yet it appears to us as if it had undergone a great change on account of its different position. (Sefer Yetzirah, Kalisch 1877) tree →

Note

Verb: rotate. Do not mix up rotation (spinning on its own axis: Earth, one day) and revolution or orbit (going around something else: the Earth around the Sun, one year). In maths, a rotation keeps the shape's size and form; only its direction changes. Anticlockwise (UK) = counterclockwise (USA).