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Earth and Space 6-8 / Week 01 / Thursday
4/6
Week 01 · Day and Night

Thursday

Reading the day-length table
// We ride a spinning Earth
⏱ about 20 min

Thursday: Reading the Day-Length Table

Raven spreads a printed table on the porch step. "NASA keeps a fact sheet for every planet. This row is length of day."

Rocket runs his finger along it. "Earth, 24 hours. Mars, 24.7. Jupiter, 9.9?" He looks up. "Jupiter spins in under ten hours?"

"What do you notice about Mercury?" Raven asks.

"Four thousand hours," Rocket reads. "One day on Mercury lasts longer than a month at home."

Nova hovers over the sheet. "Each number is one sunrise to the next sunrise on that world," she says.

Rocket grabs the ball. "Then a spot on Jupiter would zip through the light." Nova hums. "Read the rest before you spin anything."

The table from NASA

The NASA Planetary Fact Sheet lists the length of day for each planet in hours. Length of day means one sunrise to the next.

Here are the values, rounded as NASA gives them. Read every row before you answer the questions.

Remember that one Earth day is 24.0 hours. Compare every other row to that number.

WorldLength of day (hours)Compared with Earth
Mercury4222.6about 176 Earth days
Venus2802.0about 117 Earth days
Earth24.0one day
Moon708.7about 29.5 Earth days
Mars24.7a little longer than ours
Jupiter9.9less than half of ours
Saturn10.7less than half of ours
Uranus17.2shorter than ours
Neptune16.1shorter than ours

The third column is our own arithmetic: each number of hours divided by 24. NASA gives only the hours.

Notice the pattern. The big outer planets Jupiter and Saturn turn fastest. Mercury and Venus turn slowest.

A day on Mars is almost the same as a day on Earth. A clock from home would nearly keep time there.

USE THE TABLE
  • Read the question.
  • Tap your answer.
Which world in the table has the shortest day?
Which world has a day closest in length to Earth's?
About how many Earth days long is one day on the Moon?
One day on Earth lasts ____ hours, according to the fact sheet.
The world with the longest day in the table is ____.
StatementTrue or false?
A day on Saturn is shorter than a day on Earth.?
A day on Venus is shorter than a day on Earth.?
Mars has a day of about 24.7 hours.?
Every planet turns once in about 24 hours.?
WHY THIS EXERCISEEach world turns at its own rate, so each has its own length of day.
FROM SHORTEST DAY TO LONGEST
  • Tap a card.
  • Then tap its spot.
1Shortest
2Second
3Third
4Longest
Try it
Use your ball. Turn it once in ten seconds for Jupiter, then once in twenty-four seconds for Earth.
Now imagine turning it once in 4222 seconds for Mercury. That is more than an hour. Write how that would feel to the sticker.
Try this
Cover the hours column and test yourself on three rows. Record how many you got right.
Say the worlds in order from shortest day to longest day aloud.
Draw a bar chart with a bar for Earth, Mars, Jupiter and Saturn. Make each bar's length match its length of day.

Careful reading. Tomorrow you find day and night in everyday life and review the week.

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