Space Unit Packet 1

1) What is gravity?

A force that causes objects to attract to each other

2) The sun's gravity helps:

keep the Earth in orbit around the Sun

3) The moon's gravity does NOT:

keep the Earth in orbit around the Sun

4) Which object exerts the greatest gravitational force - the Sun, Earth or moon? Explain.

The sun because it is the most massive object. The more massive the object, the stronger its gravity.

5) Which object exerts the weakest gravitational force - the Sun, Earth or moon? Explain.

The moon because it is the least massive object. More massive objects (Sun + Earth) exert stronger gravity.

6) What motion is responsible for night and day?

The rotation of the Earth

7) What motion is responsible for the seasons?

The revolution of Earth around the Sun

8) What results from the movement of the moon around the Earth?

phases of the moon

9) What is the difference between rotation and revolution?

Rotation or spinning is the movement of an object around a fixed point or its axis. Revolution is the circular motion of one object around a second object.

10) What are time units used for?

To measure how long it takes natural cycles to occur

11) What is the smallest unit of time between a year, month, day, or second?

Second

12) How long does it take the Earth to make one complete rotation?

24 hours

13) The Earth actually takes 365 1/4 days to revolve around the Sun. How do we compensate for the 1/4 day?

Every 4 years we add an extra day to the year and so the year has 366 days. We add this day to February and we call this a leap year.

14) What celestial cycle results from the Earth's revolution around the Sun?

Seasons

15) The lunar cycle explains:

the different phases of the moon

16) The tidal cycle is due to:

Both Earth's rotation and the moon's revolution around the Earth

17) Which celestial cycle (seasons, day, and night, lunar cycle or tidal cycle) is the shortest? Which is the longest?

Night and day is the shortest celestial cycle. The seasons are the longest celestial cycle.

18) What season is cold and has short day and long nights?

Winter

19) The longest day of the year is:

Summer solstice

20) Spring starts on:

March 20th

21) What happens to the length of the day and night during the fall?

During the fall, the length of the day gets shorter and the length of the night get longer.

22) Compare the weather during the spring compared to the weather during autumn.

The temperature in the spring increases from cold to warm while the temperature in the autumn decreases from warm to cold.

23) What is an eclipse?

Both an instance when the Earth blocks light from reaching the moon and an instance when the moon blocks light from reaching the Earth

24) A solar eclipse only occurs during

A new moon

25) What does the moon look like during a lunar eclipse?

The moon appears red

26) What is the difference between a solar and lunar eclipse?

During a solar eclipse, the moon blocks sunlight from reaching the earth. During a lunar eclipse the Earth blocks sunlight from reaching the moon.

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