Change in density, helium balloon, heat?! help!!?

You need a small, dark colored balloon, filled with helium. Needs to have a string attached to it. Also need some paper clips or source of weight to attach to string. The object is to add enough weight so that the balloon will not rise or sink. Your last resource is a portable source of heat (hair dryer). Direct the heat toward the balloon, it should begin to rise after awhile. Explain what caused the balloon to start rise %26amp; explain why it would eventually descend when the heat source was removed or atleast reduced in strength.

Change in density, helium balloon, heat?! help!!?

The mass of He in the balloon remains constant as it is kept within the balloon. The reason the balloon rises is because density of the balloon is less than the density of air. You put the paper clips on the balloon in order to make the density of the balloon equal to the density of air. When you heat up a gas will expand. When it expands the volume it occupies increases, yet the mass remains unchanged. The definition of density is mass per unit volume. When you heat up the balloon it's volume increases. When the volume increases and the mass remains the same the density decreases and the balloon is now less dense than air and rises.

This happens every day with hot air balloon travel. As you go up in the sky the temperature gets colder. This makes the volume of the balloon lower and causes the balloon to sink as the density goes up. As the balloon drops the air is warmer and volume of the balloon increased causing the volume to increase and the density to decrease and the balloon rises. The balloon when very high in the sky goes up and down all day unless the pilot makes adjustments by firing the burner or letting air flow out.

Change in density, helium balloon, heat?! help!!?

Are u doing this lab activity for MET 1010 for Mr. Collins, Christopher T. well i think u are in my class. if u want to work together let me know.email at swami648@gmail.com