NGSS
4-PS4-2
3 lessons teach this standard. Every lesson is interactive, and every one prints as a worksheet with a separate answer key.
Grade 4 Science · Chapter 4 · Lesson 1
You see the light, not the thing.
Grade 4 Science · Chapter 4 · Lesson 2
The eye takes in. It never gives out.
Grade 4 Science · Chapter 4 · Lesson 4
Put something in the way and see.