Page 26 - Science and Technology Std 3

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DO NOT DUPLICATE

When you shout “hello” in an empty room, the sound is
reflected. In a few seconds, you hear the word “hello” again.
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This is an echo.

Activity 3 To investigate whether sound travels in water

Materials Basin, water and a small stone

Procedure

(i) Fill the basin with water.

(ii) Wait for the water to settle.
(iii) Drop a small stone in the basin.

(iv) What do you hear?

(v) Write all that you hear and observe.

Figure 2 Transfer of sound waves

When you drop anything in water, sound and waves are
produced. Water waves reflect how sound moves in water.

Therefore, sound travels in water in a similar way it does in
the air.

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PROPERTY OF UNITED REPUBLIC OF TANZANIA GOVERNMENT
Ministry of Education, Science and Technology
Science and Technology 3.indd 19 03/08/2019 11:01