Grade 1- 3
Students learn about a different method of communication.
Guglielmo Marconi invented wireless telegraphy in the late 1800s, but it was in 1901 that he was able to send radio signals through the air over great distances. Marconi had studied sound waves for many years. He created the wireless telegraphy and was successful in sending radio waves across the Atlantic Ocean, a distance of more than 2,000 miles (3,200 kilometers). The messages that Marconi sent were in Morse code, a method of communication using dots and dashes or short and long clicking sounds which represent letters of the alphabet.
Ask your students to think about the ways people communicate today. How do we send messages to people we know? How do we gather information about people and events in other countries? Create a communication web by drawing a large circle labeled "Communication." Draw lines radiating from the circle and at the end of each line, write a different form of communication we use in daily life, such as the telephone, the television, the radio, letters, newspapers, and magazines.
Impact of the Invention
Ask your children to share why they think the wireless telegraphy was an important invention. How did people communicate before this invention?
How Radio Waves Work
Demonstrate to your students how radio waves behave with the following activities:
- Tie a length of rope to a stationary pole (such as a tetherball pole). Holding the free end of the rope, manipulate it so that the rope continually moves in an "S" shape.
- Line up six croquet balls (one behind the other) for this experiment. Hit the end ball with a croquet mallet. Observe how the ball at the opposite end moves off while the others stay in place.
- Fill a shallow pan with water. Drop a marble into the center of the pan and watch the waves ripple outward from the center of the water. This can also be done by placing a clear glass or plastic pan of water atop an overhead projector. All children will be able to see the water ripples on the screen.
Have children work in pairs to investigate sound. Give them the following directions:
- Find out which travels faster, light or sound. How fast do they travel? How fast do radio waves travel?
- Conduct experiments to find out if sound can travel through water, walls, tables, soft materials, etc. Record your results and share your findings with your classmates.
- Distribute the activity sheets to students.
- Telegraphy activity sheets (two per student)