Interactive Labs › Physics labs
PPhysicsS1 to S4Meteorology
Lightning lab: how far away is the storm?
Lightning is one of the deadliest natural hazards in Rwanda. Count the seconds between the flash and the thunder, work out how far away the storm is, and decide when to go inside.
LevelS1 to S4 (and IGCSE)
TimeAbout 30 min
You useSpeed, distance, time, graphs
PriceFree: no account
🎯 Aim
To measure the distance of lightning from the time between the flash and the thunder, track a storm, and apply lightning safety rules.
You will learn to
- Calculate the speed of sound at different temperatures.
- Calculate distance = speed × time.
- Use a distance–time graph to tell if a storm is coming closer.
- Apply the 30–30 rule and choose safe shelter.
🧭 What to do
- Tap Next lightning strike and watch the stopwatch until the thunder.
- Read the distance of the strike.
- Record several strikes: is the storm coming closer or moving away?
- Change the Air temperature: how does the speed of sound change?
- Answer the questions with the class data.
- Write your conclusion and download your lab report.
📋 The data
Flash-to-thunder times measured at a school during an approaching storm (25 °C).
🧠 Investigate: answer from the data
Type your answer and tap Check. Use 💡 Hint first; open the method only when you are stuck.
📄 My lab report
Your report collects the aim, your data table, the graphs, your answers and your conclusion. It is made on your phone or computer: nothing is sent to anyone.
Check your conclusion
Light arrives almost at once, but sound travels about 346 m every second at 25 °C, so each 3 seconds between flash and thunder means about 1 km. The distances fell from strike to strike, so the storm was coming closer. When the time is less than 30 s, people should go inside a building or a closed car, keep away from trees, open fields and water, and wait 30 minutes after the last thunder.
➕ Get more from this experiment
📝 Free
Print the worksheet (button above), download the data, and save your report. Teachers can project this page in class.
📦 Premium Lab Pack
1 000 RWF
- Lightning safety poster and practical timing activity
- Storm tracking worksheet with graphs
- Teacher guide and answer key
- Exam-style questions with marking scheme
👩🏫 For teachers
Use it as a practical when apparatus is missing, as homework, or as a project. Free lesson plans help you plan, teach and assess.
🔗 Related in the subjects