Hot air balloons work because hot air rises. By heating the air inside the balloon with the burner, it becomes lighter than the cooler air on the outside. This causes the balloon to float upwards, as if it were in water.

Science tell us that hot air rises, and as the air is heated inside the balloon it causes it to rise upwards (because it is lighter than the cooler air on the outside). When the pilot needs to bring the balloon down again, he simply reduces the temperature of the air inside the balloon causing it to slowly descend.

This transfer of heat energy away from the ground by the vertical movement of air is called “free convection” or “natural convection.” A hot air balloon rises because warmer air is less dense than cool air. Since the balloon is less dense than the air around it, it becomes positively buoyant.

The law that explains how hot air balloons work is the Charles’s Law. Explanation: if gas expands when it is heated, a given weight of hot air occupies a larger volume then the same weight of cold air. Hot air is less dense than cold air.

As we know from Charles Law that with the increase in temperature its volume also gets increased. Thus, in order to make hot air balloons rise, we have to generally add heat to it, and as a result heat causes the molecules of the gas to move apart from each other.

Charles’ Law in Everyday Life In order to make a hot air balloon rise, heat is added to the air inside the balloon. When the density of the balloon decreases to be less than the density of the outside air, the balloon rises. Conversely, the volume of a gas will shrink if its temperature decreases.

The physical principle known as Charles’ law states that the volume of a gas equals a constant value multiplied by its temperature as measured on the Kelvin scale (zero Kelvin corresponds to -273.15 degrees Celsius).

Boyle’s law states that the pressure exerted by a gas (of a given mass, kept at a constant temperature) is inversely proportional to the volume occupied by it. The Boyle’s Law helps astronauts know how much of pressurized gas they can fit into a container without bursting and wasting any space.

What to do:

1. Open up the garbage bag and make the bag opening narrow using duct tape or similar.
2. Blow hot air into the garbage bag using the hair dryer directed through the now small opening.
3. After a few seconds, when the garbage bag is full of hot air, turn off the hairdryer and let go of the bag.

When a rubber balloon is rubbed against human hair, electrons are transferred from the hair to the rubber, giving the balloon a net negative charge, and leaving the hair with a net positive charge. As the balloon is pulled away, the opposite charge on the hair causes it to be attracted to the balloon.

When you bring the charged balloon near to the water it pushes electrons away, leaving a positively charged area which is attracted to the balloon. The water coming from the tap is neutral with positive and negative charges. This positively charged water is attracted to the balloon so the stream is deflected.

Rubbing the balloon against hair or wool causes electrons to move from the hair or wool to the balloon. Because electrons are negatively charged, the balloon acquires a net negative charge. The balloon’s negative charges are attracted to the positive charges in the can, and so the can rolls toward the balloon.

The balloon ends up with extra electrons, making it negatively charged. When the negatively charged balloon approaches a wall, the negative charges in the wall are repelled (or pushed away). This leaves a positive charge on the wallboard at the spot where the balloon touches.

Why does this happen? When you rub the balloon, you’re covering it with little negative charges. The negative charges are attracted to the positive charges that are in the wall. That’s why the balloon ‘sticks’ to the wall.

Hold the balloon (negatively charged) just above your head so your hair (positively charged) will be attracted to it and stand up on end. The can will start to roll towards the balloon without touching it. The negatively charged balloon repels the electrons of the can so that a positive charge is near the balloon.

11” latex balloons generally last between 12-20 hours filled with helium, and about 2-3 days when treated with Hi-Float. Foil balloons last approx. 5-7 days. Air-filled balloons generally last for a couple of weeks, but will not float.

Can I make a balloon arch the day before? In most cases, you can make the balloon arch the day before and be absolutely fine. The biggest exception would be a helium arch, which we would recommend having set up the day of the event.

6-8 weeks

Blowing Up Balloons – Hints & Tips on How To Best Fill Your Party Balloons

Balloon	Inflated Diameter	Float-Time
9″ Latex	9″	8-10 hrs
11″ Latex	11″	10-12 hrs
18″ Foil	14″ x 13″	3-5 days
20″ Foil (Str)	18″ x 18″	3-5 days

All 9 inch foil balloons are designed exclusively for air inflation as they cannot hold enough helium to float. Small foil balloons are made with a valve inside the tail at the bottom of the balloon.

How to Keep Latex Balloons Longer

1. Keep the latex balloons away from heat. Keeping them in cooler temperatures will prolong the life of the latex balloon.
2. Use a 60/40 inflater to inflate your latex balloons.
3. Spray hi-float into your balloon before using a 60/40 inflater.
4. Keep the balloon tied tightly.

Cold air doesn’t cause latex helium-filled balloons to deflate, but it does make helium molecules lose energy and move closer together. This decreases the volume inside the balloon and makes the shell of the balloon shrink and sink to the ground.

– The helium gas starts to contract around the temperature of 50-45 degrees and will decrease in volume. Once the balloon is in a warmer place the balloon will coming back to its normal size.

Store the balloons in a large plastic bag until the time for the party. This will help prevent the balloons from deflating. Tie the bottom of the plastic bag shut with the balloons inside.

Temperature is one of the biggest factors affecting how long your balloon will float. They are best kept at an even, comfortable room temperature. If the room is too hot, your balloon may burst. If the room is too cold, your balloon may start to droop.

Keep them in the cool place, and avoid the temperature fluctuations. Sunlight is a major problem for balloons, make sure you keep them safe from it.

Helium is sensitive to temperature changes. Cold air causes the helium to shrink, which makes the balloon appear to deflate, although it still floats. Heat can cause the helium to expand and the balloon to burst.

NOTE: Helium expands in the heat. Warm or hot temperatures can bring balloons down faster than their proper float time and may result in popping. DO NOT TO PUT BALLOONS INTO A HOT CAR OR LEAVE BALLOONS IN A HOT PARKED CAR.