Phases of the Moon

Phases of the moon has always been a question for me. I think we always (usually) see the moon at nights, so the earth should be between the moon and sun and as a result we should see full moon. I hope this project will help me to discover the details about this phenomena.

From http://starchild.gsfc.nasa.gov/docs/StarChild/questions/question3.html

The Moon orbits Earth at an average distance of 382,400 kilometers. The lunar month is the 29.53 days it takes to go from one new moon to the next. During the lunar month, the Moon goes through all its phases. You can see the phases drawn in the image below. Just like the Earth, half of the Moon is lit by the Sun while the other half is in darkness. The phases we see result from the angle the Moon makes with the Sun as viewed from Earth. The diagram below on the right is one you typically see in books. Don’t let it confuse you. The images of the Moon show what you see the Moon look like from Earth when it is at given points in its orbit. It does not show which side of the Moon is lit by the Sun. The side lit by the Sun is always the side that is pointed toward the Sun, as seen in the diagram below. We only see the Moon because sunlight reflectsback to us from its surface. During the course of a month, the Moon circles once around the Earth. If we could magically look down on our solar system, we would see that the half of the Moon facing the Sun is always lit. But the lit side does not always face the Earth! As the Moon circles the Earth, the amount of the lit side we see changes. These changes are known as the phases of the Moon and it repeats in a certain way over and over. At new moon, the Moon is lined up between the Earth and the Sun. We see the side of the Moon that is not being lit by the Sun (in other words, we see no Moon at all, because the brightness of the Sun outshines the dim Moon!) When the Moon is exactly lined up with the Sun (as viewed from Earth), we experience an eclipse. As the Moon moves eastward away from the Sun in the sky, we see a bit more of the sunlit side of the Moon each night. A few days after new moon, we see a thin crescent in the western evening sky. The crescent Moon waxes, or appears to grow fatter, each night. When half of the Moon’s disc is illuminated, we call it the first quarter moon. This name comes from the fact that the Moon is now one-quarter of the way through the lunar month. From Earth, we are now looking at the sunlit side of the Moon from off to the side. The Moon continues to wax. Once more than half of the disc is illuminated, it has a shape we call gibbous. The gibbous moon appears to grow fatter each night until we see the full sunlit face of the Moon. We call this phase the full moon. It rises almost exactly as the Sun sets and sets just as the Sun rises the next day. The Moon has now completed one half of the lunar month. During the second half of the lunar month, the Moon grows thinner each night. We call this waning. Its shape is still gibbous at this point, but grows a little thinner each night. As it reaches the three-quarter point in its month, the Moon once again shows us one side of its disc illuminated and the other side in darkness. However, the side that we saw dark at the first quarter phase is now the lit side. As it completes its journey and approaches new moon again, the Moon is a waning crescent.  Want another description of why the Moon has phases? You can demonstrate the phases of the Moon for yourself by using a lamp and a baseball. Place the lamp with its shade removed in one end of a darkened room. Sit in the other end of the room and hold the baseball up in front of you so that it is between your face and the lamp. Now move the ball around your head at arm’s length. Do this slowly and move your arm from right to left. As the baseball orbits your head, you will see it go through the same phases as the Moon.  Want to know what phase the Moon is in right now?

Identify Variables:

When you think you know what variables may be involved, think about ways to change one at a time. If you change more than one at a time, you will not know what variable is causing your observation. Sometimes variables are linked and work together to cause something. At first, try to choose variables that you think act independently of each other.

Variables that may affect the phases of the moon is the location of moon, earth and sun on the sky. If we draw a line from sun to the earth and draw another line from earth to the moon, the angle between these two lines affect what portion of the moon we will see. So this is one good way you may define variables.

The independent variable is the angle between moon line and sun line.

The dependent variable is the phase of the moon.

Constants are the position of the sun and experiment method.

Hypothesis:

Based on your gathered information, make an educated guess about what types of things affect the system you are working with. Identifying variables is necessary before you can make a hypothesis.

This is a sample hypothesis:

The lit part of the moon decreases as the angle between moon line and sun line increases.

This is another sample hypothesis:

My hypothesis is that the position of the moon in the sky does affect the phases of the moon. In other words when we don’t see the moon or see only a small part of the moon, are the times of month the moon will mostly be on the sky in the day, not at night. Also I think that full moon can be seen above the sky at mid night, but half moon and partial moon can not be above in the mid night and they have to be closer to the horizon.

This is another sample hypothesis:

If the sun is lighting up the side of moon that is not faced to the earth; then we will see parts of the moon that is sunny and parts that are dark. Variations of the dark and light portions we see form the phases of the moon.

Do not try to use one of the above two hypothesis. They are just sample hypotheses and hypothesis is just a guess you make after some initial studies (so it might be wrong). You must come up with your own hypothesis. In your words write why does the moon have different phases.

Experiment Design:

Design an experiment to test each hypothesis. Make a step-by-step list of what you will do to answer each question. This list is called an experimental procedure. For an experiment to give answers you can trust, it must have a “control.” A control is an additional experimental trial or run. It is a separate experiment, done exactly like the others. The only difference is that no experimental variables are changed. A control is a neutral “reference point” for comparison that allows you to see what changing a variable does by comparing it to not changing anything. Dependable controls are sometimes very hard to develop. They can be the hardest part of a project. Without a control you cannot be sure that changing the variable causes your observations. A series of experiments that includes a control is called a “controlled experiment.”

Design an experiment to show or simulate the phases of the moon.

Procedure

1. Cut and glue a piece of black construction paper to completely cover the inside cover of the shoebox.

2. Cut a piece of black thread about 2 cm long. Tape or glue the Styrofoam™ ball to one end of the thread. Tape or glue the free end of the thread to the center of the inside box cover.

3. Place the light end of the flashlight against one of the outside short ends of the box. Draw a circle the size of the flashlight on the box. Remove the flashlight and cut out the drawn circle.

4. Punch two small holes into each of the long sides of the box (see figure).

5. Punch one small hole approximately 2 in. and to the right of the flashlight hole (see figure).

6. Number the holes indicated as 1 to 5 on the figure.

7. Secure, with masking tape or modeling clay, the flashlight facing into the box through the larger hole on the short side of the box. Make sure that no light shows through.

8. Turn the flashlight on, look through each small hole, and record your observations. Draw a picture of what you observe.

What’s Going On

In this simulation, the light from the flashlight represents the light from the sun.

The Styrofoam™ ball represents the moon. The small holes in the box represent your observation of the moon from different positions of the earth. A moon phase is just the reflection of the sunlight. The moon is a satellite of the earth; therefore it travels around the earth. Only one side of the moon faces the sun. As the moon travels around the earth different sections of the moon reflect the sunlight. We call these sighted portions moon phases. The moon goes through a number of phases from new moon to full moon to quarter moon every month.

Connections

From 1969 to 1972, numerous space missions explored the moon. The moon is considered to be geologically dead. It has low surface gravity and is considered to have no water, atmosphere, vegetation, or animal life. The missions determined that the moon has dust everywhere. Lunar rocks are similar to molten rock formed on earth. Lunar rocks contain little iron and no water.

Additional Activities

Darken a room, and put a lamp in a lighted doorway. Stand in the darkened room. Hold a volleyball or any other large ball over your head in front of you. Turn your-self around and observe the light reflected on the ball.

Additional Experiments:

Make a scale model of Earth and Moon. This model will help you to get a good idea of the distances in space.

Gathered information shows:

1. The diameter of the moon is: 3,476 km
2. The diameter of the earth is 12,753 km
3. The distance from earth to moon is 384,400 km

Use these information to build a scale model of earth and moon. We want to use a 5″ ball to be the earth, what will be the diameter of the moon?

(3,476 x 5) / 12,753 = 1.36

What will be the distance from moon to earth?

(384,400 x 5) / 12,753 = 15.7

So if the diameter of the earth is 5″, the diameter of the moon will be 1.36 ” and the distance between these two is 150 inches. Get a 5″ Styrofoam ball to be the earth and another 1.3 inch ball to be the moon. Use a 150 inch tread to connect the moon to the earth. Use this setup also for your display.

Click here to see the phases of the moon now.

Materials and Equipment:

1. shoe box
2. black construction paper
3. glue
4. scissors
5. Styrofoam™ ball (5 cm)
6. flashlight (small, lightweight)
7. masking tape
8. black thread
9. hole puncher
10. pencil
11. modeling clay

Results of Experiment (Observation):

Write the result of your experiment here.

• Could you see different phases of the moon in your experiment?
• Does the phases of the moon has any relation with sun-earth-moon angle?
• Look inside the box from different holes and write what phase of the moon do you see from each hole?

Calculations:

If you do any calculation related to this project, write them in your report as well.

Summery of Results:

Summarize what happened. This can be in the form of a table of processed numerical data, or graphs. It could also be a written statement of what occurred during experiments.

It is from calculations using recorded data that tables and graphs are made. Studying tables and graphs, we can see trends that tell us how different variables cause our observations. Based on these trends, we can draw conclusions about the system under study. These conclusions help us confirm or deny our original hypothesis. Often, mathematical equations can be made from graphs. These equations allow us to predict how a change will affect the system without the need to do additional experiments. Advanced levels of experimental science rely heavily on graphical and mathematical analysis of data. At this level, science becomes even more interesting and powerful.

Conclusion:

Using the trends in your experimental data and your experimental observations, try to answer your original questions. Is your hypothesis correct? Now is the time to pull together what happened, and assess the experiments you did.

Related Questions & Answers:

What you have learned may allow you to answer other questions. Many questions are related. Several new questions may have occurred to you while doing experiments. You may now be able to understand or verify things that you discovered when gathering information for the project. Questions lead to more questions, which lead to additional hypothesis that need to be tested.

Q. What are the different phases of the moon?
A.. Many people identify 8 different phases of the moon. Here they are with a picture of what it might look like

New	Waxing Crescent	1st Qtr	Waxing Gibbous	Full	Waning Gibbous	Last Qtr	Waning Crescent

Q. How long does it take the moon to make one complete cycle?
A.About 29 1/2 days

Q. Is the phase of the moon different at different places on earth?
A. No. The phase of the moon is determined by the relative positions of the Earth, Moon and Sun, so it is the same for everyone on Earth.

Q. How can I find out when the Moon rises? Is it related to its phase?
A. Yes. The full moon rises at about Sunset. Each night, it comes up about 48 minutes later. The new moon is harder to see but it rises around the same time as the Sun.

Q. Why does the Moon look full for so long?
A. Because of the geometry of the way the light from the sun falls on the moon and is Observed by us here on earth, the full Moon and New moon seem to last longer than the other phases. But, in fact, the moon is at any particular phase for just an instant, like 12:00 noon, it happens and then it is past. This optical illusion probably contributes to many myths about things being more likely to happen when the Moon is full.

Q. But doesn’t the Moon have any effect on things on Earth?
A. Sure it does, a big one. The tug of the Moon and Sun can affect the oceans, giving us the tides. The light of a full moon can be very bright, affecting animal’s (including people) hunting habits. The full moon has been known to cause people to grab a sleeping bag, bottle of wine, loved one, telescope, drawing pad, or any combination of those items and head outside for a night under the Moon. That is pretty powerful..

Possible Errors:

If you did not observe anything different than what happened with your control, the variable you changed may not affect the system you are investigating. If you did not observe a consistent, reproducible trend in your series of experimental runs there may be experimental errors affecting your results. The first thing to check is how you are making your measurements. Is the measurement method questionable or unreliable? Maybe you are reading a scale incorrectly, or maybe the measuring instrument is working erratically.

If you determine that experimental errors are influencing your results, carefully rethink the design of your experiments. Review each step of the procedure to find sources of potential errors. If possible, have a scientist review the procedure with you. Sometimes the designer of an experiment can miss the obvious.

References:

List of References

Safety Precautions

READ AND COPY BEFORE STARTING ANY EXPERIMENT

Experimental science can be dangerous. Events can happen very quickly while you are performing an experiment. Things can spill, break, even catch fire. Basic safety procedures help prevent serious accidents. Be sure to follow additional safety precautions and adult supervision requirements for each experiment. If you are working in a lab or in the field, do not work alone.

This book assumes that you will read the safety precautions that follow, as well as those at the start of each experiment you perform, and that you will remember them. These precautions will not always be repeated in the instructions for the procedures. It is up to you to use good judgment and pay attention when performing potentially dangerous procedures. Just because the book does not always say “be careful with hot liquids” or “don’t cut yourself with the knife” does not mean that you should be careless when simmering water or stripping an electrical wire. It does mean that when you see a special note to be careful, it is extremely important that you pay attention to it. If you ever have a question about whether a procedure or material is dangerous, stop to find out for sure that it is safe before continuing the experiment. To avoid accidents, always pay close attention to your work, take your time, and practice the general safety procedures listed below.

PREPARE

• Clear all surfaces before beginning work.
• Read through the whole experiment before you start.
• Identify hazardous procedures and anticipate dangers.

PROTECT YOURSELF

• Follow all directions step by step; do only one procedure at a time.
• Locate exits, fire blanket and extinguisher, master gas and electricity shut-offs, eyewash, and first-aid kit.
• Make sure that there is adequate ventilation.
• Do not horseplay.
• Wear an apron and goggles.
• Do not wear contact lenses, open shoes, and loose clothing; do not wear your hair loose.
• Keep floor and work space neat, clean, and dry.
• Clean up spills immediately.
• Never eat, drink, or smoke in the laboratory or near the work space
• Do not taste any substances tested unless expressly permitted to do so by a science teacher in charge.

USE EQUIPMENT WITH CARE

• Set up apparatus far from the edge of the desk.
• Use knives and other sharp or pointed instruments with caution; always cut away from yourself and others.
• Pull plugs, not cords, when inserting and removing electrical plugs.
• Don’t use your mouth to pipette; use a suction bulb.
• Clean glassware before and after use.
• Check glassware for scratches, cracks, and sharp edges.
• Clean up broken glassware immediately.
• Do not use reflected sunlight to illuminate your microscope.
• Do not touch metal conductors.
• Use only low-voltage and low-current materials.
• Be careful when using stepstools, chairs, and ladders.

USING CHEMICALS

• Never taste or inhale chemicals.
• Label all bottles and apparatus containing chemicals.
• Read all labels carefully.
• Avoid chemical contact with skin and eyes (wear goggles, apron, and gloves).
• Do not touch chemical solutions.
• Wash hands before and after using solutions.
• Wipe up spills thoroughly.

HEATING INSTRUCTIONS

• Use goggles, apron, and gloves when boiling liquids.
• Keep your face away from test tubes and beakers.
• Never leave heating apparatus unattended.
• Use safety tongs and heat-resistant mittens.
• Turn off hot plates, Bunsen burners, and gas when you are done.
• Keep flammable substances away from heat.
• Have a fire extinguisher on hand.

WORKING WITH MICROORGANISMS

• Assume that all microorganisms are infectious; handle them with care.
• Sterilize all equipment being used to handle microorganisms.

GOING ON FIELD TRIPS

• Do not go on a field trip by yourself.
• Tell a responsible adult where you are going, and maintain that route.
• Know the area and its potential hazards, such as poisonous plants, deep water, and rapids.
• Dress for terrain and weather conditions (prepare for exposure to sun as well as to cold).
• Bring along a first-aid kit.
• Do not drink water or eat plants found in the wild.
• Use the buddy system; do not experiment outdoors alone.

FINISHING UP

• Thoroughly clean your work area and glassware.
• Be careful not to return chemicals or contaminated reagents to the wrong containers.
• Don’t dispose of materials in the sink unless instructed to do so.
• Wash your hands thoroughly.
• Clean up all residue, and containerize it for proper disposal.
• Dispose of all chemicals according to local, state, and federal laws.