Lesson Planning of Shadow Formed by Sunlight Subject General Science Grade 4th

 

Lesson Planning of Shadow Formed by Sunlight

Subject General Science

Grade 4^th

Students` Learning Outcomes

• After studying this lesson, the students will be able to:
• Describe the size of the shadow with the position of the sun.
• Recognize that the size of the shadow created by the position of the sun use to tell the estimated time.

Science Process Skills

Observing, Communicating, Inferring, Predicting, Measuring, Using numbers, Making models and Experimenting

Information for Teachers

• Light helps us see objects around us. The sun is the biggest source of light. When there is no sunlight we get light from torches, candles, oil lamps, electric lamps, electric tubes, and energy saver lamps.

• Shadow is formed because light travels in straight lines. When light shines on an object some rays are blocked by the object while other rays continue to travel in a straight line. The area behind the object which receives no light looks dark. This area is called the shadow. The shape of the shadow resembles the shape of the object. The length of the shadow in sunlight changes during different times of the day.
  
• When we move, our shadow moves with us.
• Our shadow changes at different times of the day.
• If we stand at the same place at different times of the day, we will find that the position and shape of our shadow have changed.

Material / Resources

Writing board, chalk / marker, duster, textbook, model of the sun, a lamp or a torch, a screen or a wall, preferably a dark room

Introduction

• The teacher will play a guessing game:
  
  
  
• Reading the sentence;

1.      I come from the

        Sun

         I am bright

         What am I?

2.      I am made of

        Something that

        Blocks a light

        What am I?

• Write the word “shadow” on the board and help students pronounce it.
• Ask the students:

1. Are they familiar with the shadow?
2. Do they always see shadows?
3. Have they ever seen shadows in a dark room?

• Ask students:

1. What do they think a shadow is?

• Ask students:

1. Have they ever raced their own shadow? Then who is the winner?
   

Development

Activity 1

• Bring a prepared poster showing few pictures of shadows of different objects. Allow the students to observe these photographs and ask them:

1. What do they see in these pictures?
2. What do they see in the first picture?
3. What do they see in the second picture and so on?
4. What made the shadow of the tree?
5. What do they think is the cause of shadow?
6. Where is the light coming from? (Left, right, behind or front)

Activity 2

Demonstration

• Required for this activity a lamp, or a torch, a screen or a wall and take all the class into a dark room. Now Use your hands to form a shadow picture on the wall.

• Place your hands in front of the light.
• Putting your hands and fingers in different positions, make interesting and different shadow pictures on the wall such as shown in the picture. 

• Ask students to work in groups. Give each group a torch and a sheet of paper. Ask them to make shadow pictures with their hands.

Activity 3

Active Learning

• Divide the class into small groups and allow them to observe their own shadow in the sun during different times of the day (morning, mid-day, afternoon)

• Ask children to record their observations and findings and share them with the class.

1. Why do the position, direction and length of the shadow change?

Quick Quiz

1. When does the longest shadow appear?
2. When do you find the shortest shadow?
3. Where is the sun at these times?

Activity 4

• The size of the shadow and the position of the sun:

• Fix a long stick upright in the school ground. Write down the length of its shadow I the following table.

 

8:30 am	10:00 am	12:00 am	1:30 pm

• What are your observations?

1. 1.      Is there shadow longer in the morning or in the afternoon?

2.      At what time is the shadow the shortest?

Discussion: Sundial

Initiate discussion with:

• Do you know how people measured time before clocks were invented?
• How can they explain the changes in a shadow cast by the shadow stick and relate it to the time of the day?

Activity 5

Making a Sundial

• Divide the class into suitable groups and ask them to follow the given instructions.
• Fix a stick (60 to 90 cm long and 1 cm thick) in a vertical position on the ground on a clear sunny day.

• Observe the shadow it casts and rule a straight chalk line along the shadow. (alternatively we can use card board and a marker)
• Mark the shadow with a peg and write the time say 8:00 am on it.
• Do the same at every hour until 5:00 pm.
• Record the length of the shadows against time on the observation chart given below.

• This is a shadow clock, the length of the shadow will tell the time. What time is it when the tip of the shadow falls on the peg nearest to the stick?

Quick Quiz:

1. What do we use instead of a sundial now?
2. When can`t a sundial be used?
3. What do you think is a problem with the use of a sundial?

Assessment Questions

1. Standing under the sun your shadow will be longest at:

(A) 8:00 am

(B)   10:0 am

(C)  12:00 pm

(D) 3:00 pm

2. Standing under the sun your shadow will be shortest at:

(A) 7:0 am

(B)  10:00 am

(C)  12: 00 pm

(D) 3: 00 pm

3.      What do you need to make a shadow?

4.      How can you make a shadow change?

5.      How do the length and direction of a shadow relate to the time of the day?

6.      Are all the lengths of the shadow stick equal after equal time intervals?

7.      Once you have made a sundial, is it accurate throughout the year?

8.      A stick is one meter high and its shadow is 1.5 meter. The shadow of a flag pole is 30 meter long. Can you work out how high the flag pole is?

• 7.      In the given picture of shadow clock, draw the shadow cast by the stick at 4:00 pm.