Temperature-related expansion of gases
we distinguish three states of matter;
that molecules move faster as the temperature increases.
to explain the phenomenon of temperature‑related expansion of gases;
to design an experiment demonstrating thermal expansionthermal expansion of gases;
The phenomenon of temperature‑related expansion is best visible in gasesgases. This is due to their structure – their moleculesmolecules move very fast. Heat makes this movement even faster, pushing molecules further apart from each other.
If we fill a balloon with gas on a cold day and then take it to a warm room, there is a risk that the balloon will break. Why? The gas contained in the balloon will expand with increasing temperature. If the balloon has already been inflated tightly, it may break.
How can we use the phenomenon of temperature‑related expansion of gases? For example, in balloon flights. Heated air increases its volume and is lighter than cold air surrounding the balloon. A hot air balloon rises because the air inside is expanded and weighs less as a result.
Before you do the “Frozen balloons” experiment, write down the research question and the hypothesis. Then follow the attached instruction. Make observations during the task, and finally - conclusions.
The balloon was filled with gas and placed at the temperature of liquid nitrogen (-196°C), at room temperature (18°C) and at the temperature of 50°C. How will the balloons behave? Find pairs.
gas molecules get closer together, causing the balloon to shrink, gas molecules get further apart, causing the balloon to expand, the size of the balloon remains unchanged
| A balloon in liquid nitrogen (-196°C) | |
| A balloon at room temperature of 18°C | |
| A balloon at the temperature of 50°C |
Summary
Thermal (temperature‑induced) expansion is a change in the volume of bodies due to a change in their temperature.
Thermal expansion of bodies is associated with an increased velocity of molecules and a rise in temperature.
Gases expand the most while being heated, but the phenomenon of thermal expansion occurs in liquids and solids too.
The phenomenon of thermal expansion must be taken into account when designing buildings and equipment.
Keywords
thermal expansion, thermal expansion of gases, hot air balloon flights
Glossary
rozszerzalność temperaturowa – zmiana objętości ciała na skutek zmiany jego temperatury
drobiny – dowolne elementy tworzące substancję, czyli atomy lub cząsteczki
gaz – stan skupienia, w którym substancja przyjmuje objętość i kształt naczynia, zajmuje całą dostępną przestrzeń