How many of you have seen a sky lantern or a hot air balloon? Many of you might have taken a ride in hot air balloons. It is fun to hover above the ground, in a basket tied to a balloon fueled by fire. Sky lanterns are mini versions of hot air balloons. It is a splendid sight to watch many sky lanterns flying together, with a tiny flame burning inside each. You need a vast open space to fly many lanterns together. But it is not a daunting task to make a single sky lantern, and fly it in the safety of your own yard or home. Safety precautions are a must! Sky lanterns and hot air balloons work on the same principles. So let us check the materials that we need for this hot air balloon science project.
What we need
Extra-light plastic garbage bag (bin liner)
Clear tape
Aluminum foil
Birthday candles (small ones)
Plastic straw
Scissors
Lighter
String
Procedure
- Cut out a square shaped piece of aluminum foil. This is the stand on which your candles will burn.
- Roll the edges of the foil and make an enclosure, so that the melted wax won’t drip down when the lantern flies.
- Take a candle and heat the bottom end using the lighter. This is done to melt the wax.
- Stick the candle inside the foil stand, before the melted wax at the bottom hardens.
- Repeat the same process with 3 more candles, while taking care to stick all of them a little apart.
- Now it is time to make the basket for our lantern. First, you need to make an X-shaped frame with plastic straws so that the plastic bag can be attached to this.
- Measure the width of the opening of your bag. Depending on this measurement, you need to make two straws of equal length.
- If your straw is not long enough, you can make a slit at the end of one, and insert it inside another straw. You can lengthen the straws to your required length.
- When both the straws are ready, attach them together in an ‘X’ shape. This can be done by sticking a tape at the middle.
- Attach the basket to all four ends of the X-shaped frame using clear tape. Ensure a minimal use of tape so that the basket will remain light-weight.
- Now you need to attach the candle stand. Stick the aluminum foil stand to all four sticks in the frame. Make sure that the candles are not touching either the straw frame, or the edge of the plastic bag. The wick should be pointing into the plastic bag.
- You are ready to light the lantern. Be very careful while doing this as the candles are now inside the bag. A long lighter will work best at this stage. Hold the bag up and away from the flame. (Parental supervision is advised)
- Wait for a while after lighting all four candles. Allow the heated air to fill the basket. Ideally, the basket should start rising up in two to three minutes.
- If you are in a large space, tie a string to the straw. You don’t want your lighted lantern to fly off and cause harm!
Explanation
Though this mini version of hot air balloon was not so easy to make, you definitely had fun! The best part is when the lantern rises up. It brings joy to see that your efforts paid off, right? So, shall we learn the science behind this hot air balloon science project?
Hot air balloons or sky lanterns work on a very basic principle of physics. When heated, air becomes less dense and rises up. In this project, we fixed the candles in such a way that the heat and smoke from burning of candles goes directly inside the plastic bag. When we burn the candles, the air inside the plastic bag heats up and becomes less dense. This air tries to move up, and causes the bag to fly along with it. If the bag or other accessories makes our basket heavy, it may not fly off. So it is important to use light-weight bags, and less tapes.
So you had fun while doing the tiny hot air balloon science project! We have more of such fun projects in our Projects section. Also check out some easy to do Experiments.
