Alpha science classroom： How To Make a Hot Air Balloon

Do the children know about hot air balloons? What is the mystery of how they fly freely in the sky? Today, the alpha science classroom teaches children How To Make a Hot Air Balloon, a children's physical science experiments project that helps children understand the principle of the hot air balloon flight and the mystery of air density. It also presents the best kid's science experiments activities to unlock the knowledge in science for kids.

Alpha Science Class: How to make a hot air balloon, need materials:

• Aluminum foil

• Birthday candles

• Scissors

• Ultra-thin trash bags (such as office trash can linings and trash bags used by dry cleaners*)

• Plastic straw (for frame)

• Scotch tape

• lighter

• Adult guardianship

• Plenty of indoor space

• Rope (if your balloon flies out of your reach)

• If you use a dry cleaning bag, you need to seal the top hole through which the hanger passes.

Alpha science classroom: How To Make a Hot Air Balloon step-by-step tutorial

Step 1: First, the children carefully cut a 4 x 4" square aluminum foil. This will be the "basket" of your hot air balloon.

Step 2: The children carefully use a lighter to melt the wax at the bottom of the candle so that it forms a pool about 1 inch from the corner of the aluminum foil.

Step 3: Before the wax hardens, the children press the end of the candle into the melted wax and keep it in place until the candle stands on its own. It may take a few tries.

Step 4: Repeat with the remaining candles, placing them 1 inch away from the other three corners. When placing it, be gentle on the basket, because pushing it too mushy can cause the candle to fall off. If this happens, just melt more wax and secure the candle in place again.

Step 5: The children fold the edge of the aluminum foil 1/4 to 1/2 inch to form a "wall" to contain the burning wax so that it will not drip outside the basket. Measure the width of the plastic bag opening and determine the length of the straw frame. We simply estimate and use trial and error until our frame fits inside the opening of the bag.

Step 6: Children use flexible straws, please cut off the bendable part and keep only the straight part. You need to fix the straw into two frames of the same length. Each of us has three straws connected together.

Step 7: To connect the straws, please cut a small slit (about 1/4 inch) at the bottom of a straw. Insert another straw into the slit. The slit will make the connection stronger, but you need to fix it with a small tape to increase the rigidity.

Repeat the second half of the frame.

Step 8: The children find the middle of the straws, glue them together in an "X" shape, and use as little tape as possible again. Place the "X" frame tightly in the opening of the bag. Use as little tape as needed to hold it in place.

Step 9: Children stagger the straw frame and the candle (so that the candle will not be directly above the straw). Tape the basket to the frame with the candlewick pointing upwards toward the envelope.

If you want to fly in an area that the balloon cannot reach, please tie the rope to the basket so you can use it during the flight.

Step 10: Children take your hot air balloon to an empty room for flight. (You can have an interview outside, but even on days when there seems to be no wind, there is usually too much wind to make such a balloon fly.) We put ours in the office lobby.

Finally, the children ask adults to help you launch the balloon. Have one person hold the closed end of the bag away from the basket while the other person lights the candle. Long-handled lighters, such as Aim'n Flame, work best. Continue to hold the bag until it is full of air and stands on its own.

After about a minute, it should leave the ground.

Alpha science classroom: How To Make a Hot Air Balloon, the science behind it

One of the important properties of alpha science classroom gas is that it expands when it gets hot and contracts when it cools. This means that when a gas is heated, the individual molecules that form it move faster and move farther apart from each other. Therefore, the gas will also become lighter as the temperature rises because the concentration of molecules is lower.

The expansion properties of gas enable hot air balloons to expand and fly. The hot air entering the balloon has a lower density of molecules, which makes the inflated balloon lighter than the cooler, denser surrounding air. The denser outside air floats and floats the balloon. Conversely, the effect of the cooling air will cause the balloon to fall back-the air molecules inside the balloon will move closer as it cools, so that the air in the balloon is no longer lighter than the surrounding air. This is why cold and humid clouds or fog are dangerous for hot air balloon pilots.

Although air appears to have no weight, it is actually formed of gas and has the same mass like any other substance. Usually, the air is composed of 78% nitrogen, 21% oxygen, 1% carbon dioxide, and rare gases. At 70 °F and one atmosphere of pressure, the density of air is approximately 0.075 pounds per cubic foot (or approximately 34 grams-slightly more than an ounce). This is why it is so important to use lightweight materials in the construction of this hot air balloon. The weight of the balloon and the air inside must be less than the weight of the ambient air being replaced in order to fly.

The children's hot air balloon successfully flew into the sky, which is the power of science. We believe that the children understood the principle of hot air balloons and the mystery of air density through this special children's physical science experiment activity, then alpha science classroom, today's kid's science experiments activity is a success, helping children to learn science knowledge and enjoy the fun of science in a happy way is our biggest dream.

Alpha science toys create a world full of science fun for children, a variety of children's physical science experiment kits, for children to solve different scientific mysteries, enjoy the magic and fun of science, and grow up to be the most powerful scientists.