# Blog

## Ride the wave – a quick quiz

By

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This quiz is all about waves. Will you ride it to victory, or will you wave goodbye to your high score?

### #1. What wavelengths are picked up by the new James Webb Space Telescope?

The James Webb Space Telescope can detect orange and red light, but mostly uses even redder, infrared light.

### #2. What happens to ocean waves when the ocean gets shallow?

Waves slow down when they hit shallow water, such as a sand bar or beach. Since the front of the wave gets there and slows down first, the wave gets taller and eventually it breaks.

### #3. True or false? Inge Lehmann discovered Earth’s inner core by studying earthquake waves.

True! Waves from earthquakes travel through the planet, and some of them reflect off the inner core.

### #4. In a symphony orchestra, which instruments are biggest?

Low notes have long wavelengths, so they need long instruments for the sound waves to resonate in.

### #5. How fast does a Mexican wave travel around a stadium?

In 2002, researchers studied 14 Mexican waves and found they moved at about 20 seats per second, and they were about 15 seats wide!

## Results

Congratulations! You are a real science whiz!

Oh dear! Better brush up before the next quiz!

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## 3 responses

1. glenn cardwell

Q5. If the answer is 20 seats/sec and they were “about 15 seats wide”, I wonder if that equates to 20×15 = 300 seats/sec (as in 20 rows x 15 columns). Put another way, 20 seats/sec sounds awfully slow for a Mexican wave and not my experience at any sporting event.

1. David

Hi Glenn,
The speed is a sideways speed only, so it travels around 20 columns of seats every second. That’s about 12 metres per second or 43 kilometres per hour.
The width is how many people in one row are standing at the same time. It equates to a bit less than a second of standing.

Paper is here:
https://doi.org/10.1038/419131a
But sadly, you’ll need to use a library to read it.

2. glenn cardwell

Thnx David, 20 columns of seats makes much more sense. I read the answer as “20 seats in total/sec” ie 20 people per second, so my original answer was 200 people per second. The link you give provides all the article, probably as it is a brief communication from 2002. Now we need a follow-up study to see if the speed has changed significantly 😉

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