Fill in the following blanks with suitable words :
A bicycle tube becomes tight on filling air because air exerts ______

Answer

To fill in the blank in the sentence "A bicycle tube becomes tight on filling air because air exerts ______," we need to understand the properties of air and gases.

1. **Understanding the Concept**: Air is a mixture of gases, and one of the fundamental properties of gases is that they exert pressure on their surroundings. This pressure is a result of the collisions of gas molecules with the surfaces they come into contact with.

2. **Applying the Concept**: When air is pumped into a bicycle tube, the air molecules inside the tube collide with the inner walls of the tube. As more air is added, the number of collisions increases, leading to an increase in pressure.

3. **Conclusion**: The increased pressure from the air inside the tube pushes against the walls of the tube, causing it to become tight. Therefore, the suitable word to fill in the blank is "pressure."

Final Answer: A bicycle tube becomes tight on filling air because air exerts **pressure**.

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