Echoes, Sonar and Ultrasound

Lab Brief #4

🎯 Your mission

Master the concept. Use it tomorrow.

⚡ The twist

Nature loves to surprise the careful watcher.

What you'll learn

Sound reflecting off a surface returns as an echo. Time it and you can find distance, because distance equals speed times half the round-trip time. Ships use this as sonar, and medicine uses ultrasound above 20 kHz to image inside the body without ionising radiation.

Key words

echo
A reflected sound heard after the original.
ultrasound
Sound above the human hearing range, roughly above 20 kHz.

Make a hypothesis first

Before you start: write down what you think will happen, and why.

Say your guess out loud — then find out if you were right.

Step 1 of 4 · Read

Think about what you just learned: say what "echo" and "ultrasound" mean in your own words before you start.

Step 2 of 4 · Do

Calculate the depth of water under a boat given an echo return time of 0.16 s and a sound speed of 1,500 m/s. Then design a labelled diagram of how an ultrasound scan builds an image from reflections at tissue boundaries.

Step 3 of 4 · Observe

Record what actually happened, including anything that did not match what you expected.

Step 4 of 4 · Record

Write a conclusion that answers the question this lesson opened with, and state your uncertainty.

Question 1 of 2

A sonar pulse returns after 0.16 s in water at 1,500 m/s. The depth is:

How sure are you?😐 maybe

Question 2 of 2

Ultrasound is defined as sound above:

How sure are you?😐 maybe

Mind = blown

🔬 The more you look, the more nature shows you.

Nice work!

You got 0 of 2 right.

Next: The Human Ear and Hearing Range All lessons

🎯

Next Smart Experiment

We'll pick an experiment that matches exactly how you're thinking right now.

✨ More to explore

🌍 Where you see this in real life: This shows up in your everyday life more than you'd think.

🏆 Stretch challenge (try it this week): Try one experiment in real life this week — even a tiny one.

👨‍👩‍👧 For the dinner table: “What's the most surprising thing you learned today?”

🔊Share card

Share this experiment

Send it to a parent who's looking for a 10-minute kitchen science win.

Echoes, Sonar and Ultrasound

Next Smart Experiment

Share this experiment

Echoes, Sonar and Ultrasound

Done with science? Try something else

Your Cart (0)