What is expansion
What is contraction
The decrease in volume of a substance when it is cooled
What happens to the liquid in thermometer when the temperature increases
The liquid expands and rises in the tube
What happens to metal railway tracks on a hot day if there are no expansion gaps
They can bend or warp due to expansion
What unit is used to measure temperature in SI
Kelvin
Why do telephon wires sag in summer but become tight in winter
They expand in heat and contract in cold
What is the main reason laboratory glassware is made of special glass?
To withstand heat and prevent cracking due to expansion
How does expansion affect bridges and buildings?
Expansion gaps are included to allow for movement and prevent damage
Why do we leave space between tiles on pavement
To allow for expansion on hot days and prevent cracking
What is an example of a liquid that expands and contracts with temperature changes?
Mercury in thermometers
What happens when water seeps under roads and then freezes?
It expands, causing cracks and road damage
How do metal pipes accommodate expansion in hot weather
They have expansion bends to allow movement
Why do hot air balloons rise
The air inside expands, making it less dense than the surrounding air
Why do bridges sometimes have rollers at their ends
To allow for expansion and contraction without structural damage
Why do car engine parts need to account for expansion
To prevent overheating and warping due to heat
What type of force is created when materials expand or contract but have no space to do so
Stress or pressure force
Why do iron pins break in the steel bar contraction experiment
The contracting metal creates strong force, breaking the pin
What happens when air trapped in a container is heated
It expands and may escape as bubbles or burst the container
Why are glass windows installed with small gaps around the edges?
To allow for expansion and prevent cracking
What scientific principle explains why a soda can or may dent inward when cooled after being heated
The contraction of air inside lowers the pressure, collapsing the can
Explain why a tight metal lids on a jar can be loosened by running hot water over it
The metal expands more than the glass jar, making it easier to open
Describe how the close fitting of metal tires onto wooden wheels uses expansion and contraction
The metal tire is heated to expand, placed on the wheel, and contracts as ot cools to fit tightly
How do railway tracks avoid damage due to thermal expansion
Expansion gaps are included between track sections to allow movement
What could happen to an underground water pipe in winter if not properly designed
Water inside can freeze, expand and burst the pipe
Why is mercury preferred over water in thermometers for measuring temperature changes
Mercury expands and contracts uniformly, does not stick to glass, and has a wide temperature range