You are asked to study the effect of temperature on a balloon. You design an experiment where you put some room temperature balloons into liquid nitrogen (a very cold substance). (a) What observations do you notice when you put the balloons into the cold liquid nitrogen? (b) What is the independent variable? (c) The dependent variable? (d) What could you hold constant to better observe the change? (e) What would be a good example of a control you could setup to make sure another variable isn't messing up your observations?

a) the balloons will shrink

b) temperature

c) volume of gas in the balloons

d) pressure and amount of the gas

e) The balloons can be set up and left at constant temperature. Possibly at room temperature to see if the same effect will be observed in it's volume.

Explanation:

Charles law states that, the volume of a given mass of gas is directly proportional to it's temperature at constant pressure.

Hence, if we manipulate the temperature of a gas (e.g by immersing it into cold nitrogen) it's volume changes in response to temperature change at constant pressure.

A balloon at constant room temperature will not experience any decrease in volume as the balloon in our experiment does.