Assignment - Infographics - 129

A Note on What Makes This an Infographic

A list of factors with one-line descriptions is a set of notes. An infographic makes the relationships visible - it shows how much the speed changes, in what direction, and why. Use actual numbers. Use visual comparisons. A reader should be able to look at your infographic and immediately see which factor has the biggest effect and which direction each one pushes the speed.

Objective

Create a visual infographic in Canva that explains how the speed of sound changes with the medium it travels through, the temperature of that medium, and humidity - using real values and visual comparisons throughout.

Content to Cover

Starting Point: What is the Speed of Sound?

Anchor the infographic: the speed of sound in dry air at 20°C is 343 m/s (approximately 1,235 km/h). Everything else in the infographic shows how this number changes and why.

Factor 1: The Medium

Sound travels as a pressure wave - it needs molecules to push against. The closer together the molecules (denser and more elastic the medium), the faster the wave moves.

Include a visual comparison bar showing speeds in:

• Air at 20°C: 343 m/s
• Fresh water at 25°C: 1,480 m/s
• Steel: 5,960 m/s
• Vacuum: 0 m/s (sound cannot travel - no molecules)

Explain why: in steel, molecules are tightly packed and highly elastic, so the compression passes from molecule to molecule almost instantly. In air, molecules are far apart, so the transmission is slower.

Factor 2: Temperature

In gases, higher temperature means faster-moving molecules, which transmit the pressure wave more quickly. The relationship is approximately: for every 1°C rise in temperature, the speed of sound in air increases by about 0.6 m/s.

Include a small comparison:

• Air at 0°C: 331 m/s
• Air at 20°C: 343 m/s
• Air at 40°C: 355 m/s

Real-life relevance: on a hot day in Karachi (40°C), sound travels faster than on a cool winter morning.

Factor 3: Humidity

Humid air (air with more water vapor) allows sound to travel slightly faster than dry air. Water molecules (H₂O) are lighter than the nitrogen and oxygen molecules they partially replace, allowing the pressure wave to move more easily.

Note: humidity has a smaller effect than temperature or medium. It is worth mentioning but should not be given equal visual weight to the other two factors.

Putting It Together

Add a brief summary panel: The biggest factor is the medium. Within a given medium, temperature is the main variable. Humidity has a minor effect in air.

Design in Canva

• Use horizontal bar charts or arrow visuals to show speed comparisons numerically.
• Give each factor its own section with a clear heading.
• Use a consistent speed scale so the bars for different media can be compared visually.
• The vacuum (0 m/s) bar should be visually striking - no bar at all, just a label.

Required Elements

• Speed of sound in at least 4 media with actual values.
• Temperature effect shown with at least 3 temperature values.
• Humidity explained with its effect noted as minor.
• A summary panel comparing the relative importance of each factor.
• Title: “Factors That Affect the Speed of Sound.”