Comets are large balls of ice, rock and dust but you can think of them as large dirty snowballs that travel through the Solar System. The main part of a comet is called the nucleus. Most of the time comets are too faint and dark for us to see, but as they get closer to the Sun, the ice starts to heat up and some of it turns into gas. The gas and dust released forms an enormous tail that stretches out behind the nucleus.
Why not make a model to explore the different parts of a comet!
By the end of this activity you will:
- have made a model of a comet
- seen what happens as it orbits close to the Sun
To complete this activity you will need:
- a stick - maybe from the garden or a drinking straw
- sticky tape
- a ball of scrunched up paper or play-doh
- cotton wool
- cling film, bubble wrap, or tissue paper
- ribbon or strips of tissue paper
- a hairdryer
Credit:NASA
Have a go!
Safety information!
- Don't run with your stick
- Put some tape or something similar over the end of the stick if it sharp
- Careful not to trip over the hairdryer wire
- Keep the hairdryer on a low heat temperature, beware of burning
Part 1: Follow the instructions to make your comet. The information tells you what each part of your model represents!
| Instructions | Information |
| Attach a ball of scrunched-up paper or play-doh to the top of your stick. It should look a bit like a lolly-pop. | The main ball is called the nucleus. It is like a dirty snowball made of ice and rock. The stick is just for holding your model. It is not part of the comet. |
| Add some smaller balls of cotton wool to the main ball. | As the comet gets closer to the Sun, the surface of the comet's nucleus warms up and ice starts to melt off along with some dust. |
| Wrap the bumpy ball in cling film, bubble wrap or tissue paper. | The ice and dust make a cloud around the nucleus called a coma. Sunlight reflects off the coma and makes it glow brightly. |
| Stick ribbons or strips of paper to the ball to create a 'tail'. Let them drop down naturally (don't try and force them to trail). | The is the gas and dust that gets pushed into a tail by the Sun - you'll see how in part 2 of the activity. |
Part 2: Fly your comet around the Sun!
For this part you need the hairdryer and another person to help.
Follow these instructions:
- The first person holds the hairdryer and points it at the comet at all times. The hairdryer represents the solar wind that blows from the Sun.
- The second person holds the comet by the stick and moves in a large oval shape around the Sun (the person holding the hairdryer) - comets orbit the Sun in elliptical (egg-shaped) orbits.
- As the comet gets closer to the Sun, the comet's tail is pushed away by the wind from the hairdryer.
- As your comet travels far away from the Sun, the tail of the comet will drop - this shows the Sun has less of an effect on a comet when the comet is further away.