An angle is a measure of turn. When we talk about the angle between two lines we are not referring to the shape formed by the two lines, nor to the point where the lines meet, nor to the space between the lines, but to the size of the rotation involved when you point along one line and then turn to point along the other.
There are always two angles involved when turning from one direction to another: clockwise and anticlockwise.
A quarter turn is called a right angle because it is an upright angle. A half turn, formed by two straight lines pointing in opposite directions, is sometimes called a straight angle.
Children in Key Stage 1 should describe and make whole, quarter, half and three quarter turns, clockwise and anticlockwise. They should know that a quarter turn is called a right angle and be able to identify right angles in shapes and patterns, and in the environment.
Children should also be able to use mathematical language to describe position, direction and movement, for example, when they give instructions to a partner on how to build a simple shape from squares and triangles or when they direct a programmable toy.
Can you show me a quarter turn?
One possible answer is. The hands on the clock at a quarter past 12, and although this is only an approximation of a quarter turn as the hour hand will have moved beyond 12, children are familiar with this context and can make their own clocks from a paper plate and a split pin.
There are many other examples in a wide range of contexts that are relevant to children’s experiences.
Have a treasure hunt in the classroom. In pairs, one child hides an object and gives instructions for their partner to find the 'treasure'. Their instructions should include turning through right angles left or right. Both then draw the route on paper.
Work on angles builds on everyday experiences in the classroom and beyond.
Toys such as spinning tops, wind−up cars and telephone dials offer rich opportunities to develop an understanding of turning.
Children quickly recognise that there are differences in the amount of turn. This leads to discussions about the size of these different turns as quarter, half and whole turns.
When children understand the size of a turn they can begin to record the size of the turn that has taken place as an angle. Using geostrips to measure the size of a turn when you open the door helps to emphasise that angle is a measure of turn.
At Key Stage 2 children begin to quantify the size of the angles in degrees and learn to use protractors to identify, measure and draw angles of different sizes in shapes.
Turning and twisting
Discussions about acrobats, ballet dancers, diving, skateboarders and other contexts support the pupils' understanding of movement and turn. Where have you seen someone turn a whole turn in the air?