- 4.MD.5. Recognize angles as geometric shapes that are formed wherever two rays share a common endpoint, and understand concepts of angle measurement:
(Common Core Mathematics /// Grade 4 /// Measurement And Data /// Geometric Measurement: Understand Concepts Of Angle And Measure Angles)

- 4.MD.6. Measure angles in whole-number degrees using a protractor. Sketch angles of specified measure.
(Common Core Mathematics /// Grade 4 /// Measurement And Data /// Geometric Measurement: Understand Concepts Of Angle And Measure Angles)

- 4.MD.7. Recognize angle measure as additive. When an angle is decomposed into non-overlapping parts, the angle measure of the whole is the sum of the angle measures of the parts. Solve addition and subtraction problems to find unknown angles on a diagram in real world and mathematical problems, e.g., by using an equation with a symbol for the unknown angle measure.
(Common Core Mathematics /// Grade 4 /// Measurement And Data /// Geometric Measurement: Understand Concepts Of Angle And Measure Angles)

- 4.G.1. Draw points, lines, line segments, rays, angles (right, acute, obtuse), and perpendicular and parallel lines. Identify these in two-dimensional figures.
(Common Core Mathematics /// Grade 4 /// Geometry /// Draw And Identify Lines And Angles, And Classify Shapes By Properties Of Their Lines And Angles)

- 4.G.3. Recognize a line of symmetry for a two-dimensional figure as a line across the figure such that the figure can be folded along the line into matching parts. Identify line-symmetric figures and draw lines of symmetry.
(Common Core Mathematics /// Grade 4 /// Geometry /// Draw And Identify Lines And Angles, And Classify Shapes By Properties Of Their Lines And Angles)

- Make observations to construct an evidence-based account that objects can be seen only when illuminated.
(Next Generation Science Standards /// Grade 1 /// Physical Science /// Waves and their Applications in Technologies for Information Transfer )

- Plan & conduct an investigation to determine the effect of placing objects made with different materials in the path of a beam of light.
(Next Generation Science Standards /// Grade 1 /// Physical Science /// Waves and their Applications in Technologies for Information Transfer )

- Develop a model to describe that light reflecting from objects and entering the eye allows objects to be seen.
(Next Generation Science Standards /// Grade 4 /// Physical Science /// Waves and their Applications in Technologies for Information Transfer)

- Develop & use a model to describe that waves are reflected, absorbed, or transmitted through various materials. [Both light & mechanical waves. ]
(Next Generation Science Standards /// Middle School /// Physical Science /// Waves and their Applications in Technologies for Information Transfer )