This activity is fun for the whole family, as they become "scientists" discovering comet facts and building them into their own "make and take" comet model. Make this simple model of a comet with paper and streamers. It's a good model for some facts about a comet, and for others, it is not. Let your families decide what the strengths and weaknesses are for their comet models.
To enhance the activity have your "scientists" pick two or three things that are true about comets and use household recyclable items to make their comet more accurate. Post or make available either "Ten Important Comet Facts" or the "Comet Acrostic" so they can pick their facts about comets. Gather your recyclable items from old wrapping, packing and other choices from the materials list. If you need to know more about comets, visit deepimpact.umd.edu and stardust.jpl.nasa.gov to learn more about the Deep Impact and Stardust missions.
One 8 1/2" X 11" sheet of paper
Two 1 - 2 ft lengths of mylar gift strips or long tinsel
One 2" strip of tape
One non-bending drinking straw
An electric hairdryer/electrical power available
One marker pen
Gather household or art supplies so that the participants can improve/build new models.
|Raffia or gift grass
|Pearlescent wrapping paper
|Pipe cleaners (minimum 3 colors)
|Any material that glitters or reflects light
|Yarn (minimum 3 colors)
||Old packing materials
||Peanuts in the shell
|Look for wrapping, packing, and other materials that have stiff or reflective surface to use for building comet models. Use your own ideas from what you find at home.
- Cut or tear the corners of your sheet of paper to 2 inches of the center of the page.
- Place the mylar strips evenly one across each paper slit so they form an X on the paper.
- Crumple the paper into the shape you think best represents a comet and make sure that your strips of mylar stay to the outside of your crumpled paper and can fly like streamers.
- Make an opening in your comet to insert a straw and tape it together so your comet is now on a stick.
Here's what you do:
Use a hairdryer to simulate the heat from the Sun. As the comet travels closer to the Sun, the Sun heats the comet. Heated gases drive off ice and dust from the nucleus of the comet and into the vacuum of space forming a halo around the nucleus called the coma. The hairdryer also simulates "solar wind" which is a force that results as light leaves the Sun and speeds into the darkness of space. The solar wind pushes some of the coma's material to the backside of the nucleus so that it trails behind the comet to form a tail as it speeds along its orbital path around the Sun.
Have Leader #1 be the "Sun" and stand in place with the hairdryer. The hairdryer simulates the solar wind causing the comet tail (mylar) to form and trail behind the comet. Aim the hairdryer at the comet as it approaches and as it moves away. The "Sun" will have to turn in place to keep the "solar wind" flowing evenly to the comet. Leader #2 holds the comet by the straw and walk in an elliptical orbit around the Sun. As the comet gets closer to the Sun, the solar heating and solar wind affects the comet so that the coma and tail forms (the tinsel rises up) and so that it stays in opposition to the Sun (always going the opposite direction from the Sun). As it travels away, the loss of heat causes the coma to diminish and the tail to dissipate (or in this case, collapse).
Questions: Use the materials you gathered to have participants improve or build new models.
- How does this model succeed in showing the influence of the Sun on a comet?
- What other elements of a comet can be seen using this model?
- Which elements of a comet are not well shown by this model?
- Can you improve the model by changing it or making an entirely new model?
- Choose two things scientists believe are true about comets and use recyclable materials to improve your model.
Tips for the Activity Leader:
- A hairdryer only sends "wind" from one side while the Sun would be sending out solar wind from all sides.
- This model does form a tail with the solar wind but it fails to show that the material that outgasses from the comet also shoots forward. This is why we see the front of the comet glow but do not directly see the nucleus of the comet which is hidden further back inside the comet's coma.
- This model does not show that the tail of a comet appears curved because in space we see a "history of the tail". At any point in time, particles move directly away from the Sun (as in this model). Over time, as the comet curves around the Sun on its orbit path, the particles leave a tail that is curved (not shown in this model).
- As the comet moves away from the Sun, the model tail droops. In space, the particles and debris continue to be swept away from the nucleus, but the production rate of debris decreases.
- Comets are not white since the rock and debris being outgassed clings to the surface of the comet in a crust that is blacker than toner for a copy machine. Comets also appear in different irregular shapes and are not "balls". They are shaped more like potatoes. Scientists are not sure how rough or smooth the surface of a comet might be and will get that information from the missions currently planned by NASA.
Questions? Contact: Maura.Rountree-Brown@jpl.nasa.gov