Did you know that heat can change the shape and size of objects? This common science concept is called thermal expansion. From railway tracks to bridges, we see thermal expansion examples all around us.
Let’s understand what is thermal expansion, explore 10 detailed real-life cases, and learn how Atal Tinkering Labs (ATLs) and the ATALUP STEM App help students explore this concept through hands-on learning.
What is Thermal Expansion?
It means that most materials expand when heated and contract when cooled. The reason behind this is simple: heat gives more energy to the particles inside the material, and they start vibrating more and move apart.
This change in size is more noticeable in solids like metals. It’s a very important concept used in engineering, construction, and even daily household tasks.
Thermal Expansion Formula
To calculate how much a material expands, we use this thermal expansion formula:
ΔL = α × L × ΔT
Where:
- ΔL = Change in length
- α = Coefficient of linear expansion (material-specific constant)
- L = Original length
- ΔT = Change in temperature
This thermal expansion formula helps in designing machines, buildings, and structures that need to handle temperature changes.
10 Thermal Expansion Examples in Real Life
1. Why Railway Tracks Have Gaps
Railway tracks are made of metal, and metal expands when heated. During hot summers, the metal expands and needs space to grow. That’s why engineers leave small gaps between the tracks. Without these gaps, the tracks could bend or break due to pressure. This is a perfect thermal expansion example in transportation.
2. Opening Tight Jar Lids with Hot Water
Sometimes jar lids, especially metal ones, are very tight. Running them under hot water causes the metal lid to expand slightly due to the expansion. As it grows bigger, it loosens up and becomes easier to twist open. It’s a simple trick that uses science at home!
3. Electric Wires Appear Loose in Summer
In summers, you may notice that the electric wires hanging between poles look a bit loose or saggy. This is because the wires expand due to heat. In winter, the wires contract and become tighter. Engineers consider this expansion while installing power lines.
4. Why Bridges Have Expansion Joints
Bridges are long and often made from metal and concrete. To avoid cracks or breaks, builders include expansion joints, small gaps that allow the materials to expand during the heat of the day. Without these joints, thermal expansion can damage the entire bridge.
5. Thermometers Work Because of Thermal Expansion
Older thermometers with mercury or alcohol work on thermal expansion. As temperature increases, the liquid inside the thermometer expands and rises up the tube, showing the temperature level. It’s one of the earliest instruments based on this concept.
6. Why Glass Cracks with Sudden Heat
If you pour boiling water into a glass that was in the fridge, it may crack. This happens because the inside of the glass heats up and expands quickly, while the outside is still cold and doesn’t move much. This difference in expansion causes the glass to break — a clear thermal expansion example at home.
7. Gaps Between Concrete Road Slabs
You might have noticed small gaps between concrete slabs on roads or pavements. Concrete also expands in heat. These gaps give space for the material to grow and prevent it from cracking. Without planning for thermal expansion, roads would get damaged easily.
8. Hot Air Balloons Rise Due to Expansion
When air inside a balloon is heated, it expands and becomes lighter than cold air. This causes the balloon to lift off the ground. The science behind hot air balloons is directly related to the thermal expansion of gases.
9. Electric Irons Have Bimetallic Strips
Electric irons have a bimetallic strip inside, made of two different metals. When the strip gets hot, each metal expands at a different rate, and the strip bends. This bending is used to cut off the electricity once the iron is hot enough. It’s a clever use of thermal expansion in appliances.
10. Water Pipes Can Burst in Temperature Changes
During extremely cold weather, water inside pipes can freeze and expand, causing the pipes to burst. Similarly, in high heat, the pipe material can expand and weaken. Plumbers use this knowledge of thermal expansion to choose proper materials and design.
How Can Students Learn Thermal Expansion in ATL Labs?
In Atal Tinkering Labs, students can do simple experiments to understand thermal expansion practically. Some ideas include:
- Heating a metal rod and measuring how much its length changes
- Watching a balloon expand when hot air is blown into it
- Studying how a bimetallic strip bends with heat
These STEM activities help students see what is thermal expansion with their own eyes. They learn not by memorizing, but by doing.
How ATALUP Helps Schools and Students
Setting up and running an Atal Tinkering Lab can feel difficult, but ATALUP makes it easy. We help schools from start to finish:
- Apply for the ₹20 lakh ATL grant
- Install and manage the ATL lab
- Train teachers and support STEM implementation
But that’s not all. ATALUP also offers a free STEM Learning App to registered schools.
Through the ATALUP STEM App, students can:
- Explore science activities like thermal expansion at home
- Take part in a 21-Day STEM Challenge
- Solve fun quizzes and practice hands-on experiments
- Build curiosity even before stepping into the ATL lab
This way, ATALUP helps create a strong foundation in science and builds a habit of innovation among students.
Download the app now
Android: Play Store and iPhone: Apple Store
Final Words
Understanding thermal expansion is important not just for exams, but also to make sense of the world around us. From opening a jar to designing a bridge, this science concept is used everywhere.
Thanks to Atal Tinkering Labs and the ATALUP STEM App, students now have the tools to explore such ideas in real life. Let’s give them the chance to think, experiment, and innovate.