Students who demonstrate understanding can: Develop and use a model to describe that waves are reflected, absorbed, or transmitted through various materials.
Clarification statement: Emphasis is on both light and mechanical waves. Examples of models could include drawings, simulations, and written descriptions.
Assessment boundary: Assessment is limited to qualitative applications pertaining to light and mechanical waves.
Official wording from the Next Generation Science Standards (NGSS Lead States, 2013). NGSS is a registered trademark of WestEd. Neither WestEd nor the lead states and partners that developed the NGSS were involved in the production of this page, and they do not endorse it. View on nextgenscience.org
When a wave reaches a new material, three things can happen, often all at once. Some of the wave bounces back (reflection), some passes through (transmission) and some is taken in and turned into thermal energy (absorption). Which one dominates depends on the material and the type of wave.
For light, a mirror reflects most of it, clear glass transmits most of it, and a black shirt absorbs most of it and warms up. Light also bends as it passes from air into water or glass, which is why a straw looks broken in a glass of water. For sound, hard smooth walls reflect it and cause echoes, while soft carpets, curtains and foam absorb it, which is why an empty gym is loud and a furnished bedroom is quiet. Sound needs a medium, so unlike light it cannot cross empty space.
Students build models such as ray diagrams, drawings, simulations and written descriptions that predict what happens when light or mechanical waves meet different materials. Explanations are qualitative.
A window both transmits and reflects light, which is why you see your reflection at night. Most materials do a mix of all three.
We see objects when light reflected from them enters our eyes, not because our eyes send out rays.
Movie explosions in space are fiction. Sound needs particles to travel through, and space is nearly empty.
Black objects absorb most visible light and reflect very little, which is why they look dark and heat up in sunlight.
Use the ideas of reflection and absorption to explain why an apple looks red in white light and almost black under blue light.
Answer: An object's color comes from the light it reflects. The apple reflects red and absorbs other colors, so with no red light available it appears nearly black.
Shine a flashlight at a mirror, a sheet of clear plastic, wax paper and black card, and have students record what they see on the wall and on the material. Repeat with a sound source near a bare wall and a pillow. Students then draw models showing arrows for reflected, transmitted and absorbed parts.
Assessment may ask students to choose the best material to soundproof a room, to complete a ray diagram, or to explain a color using a model. Encourage arrows and labels on every diagram.
Original questions written for this standard. Choose an option or type your answer, then press Check. Every question has a worked explanation.
Answer: D) Thick fabric curtains and foam panels
Soft, porous materials absorb sound rather than reflecting it, which reduces echoes.
Answer: reflection (also accepted: reflecting)
Reflection is when a wave bounces off a surface, like light from a mirror or sound from a cliff.
Answer: B) Sound needs a medium and space is nearly empty
Sound is a mechanical wave that needs particles to travel through. Space has almost none.
Answer: C) transmits light
Clear glass lets most light pass through, which is transmission, though it reflects a little too.
Answer: D) Black paint absorbs more light, turning it into thermal energy
Black surfaces absorb most visible light and convert it to thermal energy; white surfaces reflect most of it.
Answer: transmission (also accepted: it is transmitted, transmitted)
Light that passes through a material is transmitted.
Plan and conduct investigations to determine the effect of placing objects made with different materials in the path of a beam of light.
Develop a model to describe that light reflecting from objects and entering the eye allows objects to be seen.
A full lesson with slides, activities and an exit ticket on reflection, absorption and transmission, pitched to grades 6-8 and editable in PowerPoint or Google Slides.
Make a lesson βA printable, differentiated worksheet on MS-PS4-2 with an answer key, ready in about a minute.
Make a worksheet βTurn reflection, absorption and transmission into a quiz students answer online that marks itself, with a class summary for you.
Build a test βYes. The emphasis is on both light and mechanical waves such as sound and water waves, using qualitative models.
No. Assessment is limited to qualitative applications, although drawing ray diagrams is a common way to model reflection and bending.