Question

As weather balloons rise from the earth's surface, the pressure of the atmosphere becomes less, tending to cause the volume of the balloons to expand. However, the temperature is much lower in the upper atmosphere than at sea level. Would this temperature effect tend to make such a balloon expand or contract? Weather balloons do, in fact, expand as they rise. What does this tell you?

Short answer

In summary, weather balloons expand as they rise due to the decrease in atmospheric pressure, which has a more significant impact on the volume than the decreasing temperature. According to the Ideal Gas Law, the decreasing pressure as the altitude increases causes the volume of the balloon to expand, overcoming the volume decrease that temperature might cause.

Step-by-step solution

Recall the Ideal Gas Law

The Ideal Gas Law relates the pressure (P), volume (V), and temperature (T) of an ideal gas using the gas constant (R) and the number of moles (n) of gas. The equation is expressed as: \[PV = nRT\]

Analyze the effect of pressure on volume

As a weather balloon ascends, the atmospheric pressure decreases. According to the ideal gas law, if the pressure decreases while the number of moles of gas and temperature remain constant, the volume of the gas will increase.

Analyze the effect of temperature on volume

The temperature of the atmosphere also decreases as the balloon rises. According to the ideal gas law, if the temperature decreases and the pressure and number of moles of gas remain constant, then the volume of the gas will also decrease.

Determine the dominant effect on volume

Since the pressure and temperature both affect the volume of the weather balloon, we need to determine which effect is dominant. We know that weather balloons expand as they rise, which means the decrease in pressure has a greater effect on the volume than the decrease in temperature.

Conclusion

Based on our analysis, the decrease in atmospheric pressure has a more significant impact on the volume of weather balloons as they rise than the decrease in temperature. As a result, the balloons expand even though the temperature decreases, because the dominant factor is the decreasing pressure as the altitude increases.