Tools/materials: two large balloons (hydrogen balloons or ordinary balloons), string or thin iron wire, alcohol lamp or heater, iron frame or support, matches or igniter.

Steps/methods:

1. Inflate two large balloons and make sure they are airtight.

2. Make a small hole in a big balloon, pass a thin rope or wire through the hole and fix it.

Put this big balloon on a stable iron frame or bracket.

4. Put the alcohol lamp or heater under the balloon, light the heater and start heating.

When the air in the balloon is heated and expanded, the shape of the balloon will change and it will start to take off.

6. When the balloon is lifted off, the flying direction and height of the balloon can be controlled by pulling the string or thin thread.

7. When the balloon needs to land, you can turn off the heater and let the air inside the balloon cool down, and the balloon will gradually descend.

8. After use, completely release the air in the balloon and keep it properly for later use.

Matters needing attention in making hot air balloons:

1. Select the appropriate balloon material: In order to keep the balloon shape and prevent the balloon from bursting, you can choose to use professional balloon materials, such as polyester film or nylon cloth.

2. Reasonable control of heating temperature: The flying height and stability of a hot air balloon depend on the temperature of the heated balloon. You can control the heating temperature by adjusting the flame size of the heater to keep the balloon flying stably.

3. Making tail wings: In order to better control the flight direction of the balloon, some tail wings can be made, such as cutting cardboard into triangles and fixing them at the bottom of the balloon to increase the stability of the balloon.

4. Pay attention to the inflation and deflation of balloons: When making and using hot air balloons, you need to pay attention to the inflation and deflation of balloons. If the balloon is inflated excessively, it may cause rupture or unstable flight; If the balloon does not have enough air, it may lead to insufficient lift-off height or failure to maintain stable flight.

5, pay attention to safety issues: when making and using hot air balloons, you need to pay attention to safety issues. Especially when using heaters, matches and other flammable items, we should pay attention to avoid accidents such as fire or scald.

6. Abide by relevant laws and regulations: When using hot air balloons in public places, you need to abide by relevant laws and regulations. Only after obtaining the necessary permission and observing the flight rules can the hot air balloon be used safely.