Now do this put-the-text-back-together activity.
This is the text (if you need help).
Today, many things are getting shorter. Scientists have just measured something very short. They recorded the shortest unit of time ever measured - a zeptosecond. This is a tiny, tiny fraction of one second - a trillionth of a billionth of a second. It is a decimal point followed by 20 zeros and then a 1. The scientists study atomic physics at the Goethe University. They used high-tech equipment to measure how long it takes a photon to cross a hydrogen molecule. The scientists said it took 247 zeptoseconds for this to happen. This is too fast for humans to sense or see.
In 1999, an Egyptian won the Nobel Prize in Chemistry for measuring the speed at which molecules change their shape. He found that one femtosecond equals 0.000000000000001 seconds, or a millionth of a billionth of one second. The zeptosecond measures things in terms of the speed of light. One millisecond is a thousandth of one second. This is the time it takes a neuron in our brain to fire. One nanosecond is one billionth of one second. The shortest unit of time it may be possible to measure is one Planck. This is a decimal point followed by 44 zeros and a 1.
Back to the zeptosecond lesson.
