Lesson Plan #: AELP-PHS0058
Date: April 27, 1999
Grade Level(s): 4, 5
Subject(s):
Description: Students will gain an understanding that light travels in a straight path and in all directions.
Goals: Unit: Light
Students will realize that light travels in a straight path and in all directions through prediction and exploration.
Objectives: Students will:
1. explore what they know about how we see things and how light travels
2. observe light boxes and share ideas about shadows and how light travels
3. describe what they observed in their groups
4. relate what they did in their groups to what they already thought about properties of light
5. predict how light will be projected on a screen through a small hole
6. demonstrate their understanding that light travels in a straight path in all directions by predicting,
observing and drawing a diagram.
Materials:
ENGAGE:
Objectives:
Students will explore what they know about how we see things and how light travels.
Procedure:
1. Ask students to think about how we see things.
2. Have them respond to the question orally in class.
3. After some ideas have been expressed, have the students write and/or draw on a piece of paper how they think light travels.
4. Students will describe what they observed in their groups.
5. Students will relate what they did in their groups to what they already thought about properties of light.
EXPLORE:
Objectives:
Students will observe light boxes and share ideas about shadows and how light travels.
Materials:
For each group of students:
1. Divide student into groups of 3-4.
2. Turn the lights off in the room.
3. Have each group explore properties of light using the light boxes, materials provided, and whatever else they want to use.
4. Ask them to think about some hypotheses about how light travels.
EXPLAIN:
Objectives:
Students will describe what they observed in their groups.
Students will relate what they did in their groups to what they already thought about properties of light.
Materials:
1. Have each group of students describe what they did in their groups and the observations they made.
2. Ask what conclusions they made about how light travels
(N.B. Ask questions until they come up with facts supporting the idea that light travels in a straight path and in all directions).
3. Have volunteers come up to the board and draw a diagram of how the light was projected on the screen using arrows to describe where the light falls on the screen and what direction it travels. If the students haven't quite grasped the concept, keep asking questions and calling on volunteers
to complete the diagram on the board.
4. After the students have grasped the concept that light travels in a straight path and in all directions, have them develop statements about light.
They should eventually come up with something similar to the following:
-Light travels out, either by being reflected or being produced, from all points on an object in all directions.
-Light travels in straight lines.
ELABORATE:
Objectives:
Students will use previous understanding of light to predict how light will be projected on a screen through a small hole.
Materials:
1. Poke a small whole in the black paper large enough for light to pass through and project on the screen (probably a little larger than a pinhole).
2. Ask students: "Knowing what you learned about light, what do you think the image will look like on the screen once
I turn the light on and place it in front of the hole?" (
Accept all answers
)
3. Have students draw on a piece of paper what they think the image will look like.(
Many students will probably predict that the image will be a point of light because of the hole and not realize that the light bulb, being oblong, will be what appears on the screen.
)
4. Turn off light and perform the experiment. (
The image will be small so students may have to gather around close to see the image on the screen
.)
5. Ask if their predictions were right. (
The image of the light will be a straight line up and down
)
6. Have volunteers come up to the board and draw a diagram of the light passing through the hole and onto the screen.
Assessment:
EVALUATE:
Objectives:
Students will further demonstrate their understanding that light travels in a straight path in
all directions by predicting, observing and drawing a diagram.
Materials:
Same as previous step.
Procedure:
1. Have students work in groups to come up with a prediction of what the image will look like if the same experiment was done in the previous step but the top half of the light is bulb is blocked.
2. Block the top half of the light to show that what's projected on the screen is an upside down image of the light. (
Only the bottom half of the image will show on the screen
.)
3. Ask students if anyone predicted this and why this happens. (
Students answers should reflect understanding that light travels in a a straight path in all directions
)
4. Have the students work in groups and draw a diagram of why this happens.
5. Ask volunteers to come up to the board and draw and explain the diagram.