:: Description ::
In this activity groups of visually impaired students and their sighted peers are invited to use daily basis items and recycled materials to build a tactile schematic image of a celestial object from our solar system. In a group activity, they are also encouraged to research about our celestial neighbour and its main characteristics.
This activity is planned for groups of children from 6 to 12 years old and their educators gathered in groups of 3 to 5 children (for example: 3 sighted children and 2 visually impaired). The activity can be implemented at three stages that can be done separately:
- Research on the celestial object by the children prior to the activity;
- Build the tactile image in a hand-on performed by the sighted children closely interacting with their visually impaired peers;
- Tactile exploration of the final schematic image by visually impaired children.
Variations of the activity can also be conducted. For instance, promote activities for sighted children in which they learn and build the tactile images and then promote explanatory sessions to their visually impaired peers.
In all stances it is strongly advised to stimulate interactions between sighted children and their visually impaired peers.
:: Materials ::
Tactile features present in Halley’s Comet and correspondent suggested textures:
These materials are only suggestions, all textures can be replaced by local low cost materials from each community that plans to implement “Meet our Neighbours!”. –
:: The Scientist Explains ::
Comets are small objects that orbit the Sun at very large distances, hundreds to thousands of times the Sun-Earth distance. They are believed to form a huge cloud, called the “Oort cloud”, around the solar system. Some of these comets may be dislodged from their distant location by the gravitational influence of Jupiter, and their new orbits take them on a long journey across the solar system.
Most of the comets that enter the solar system never come back for a second visit, but some become periodic comets, with periods that vary from less than 200 years (short-period comets) to thousands of years (long-period comets). In the case of Halley’s comet, it’s very elongated orbit takes it as far as 5250 million kilometres and as close as 87 million kilometres from the Sun over a period of 75.3 years.
The passages of Halley’s comet have been recorded by astronomers since at least 240 BC, but they were not recognized as periodic visits by the same object. It was only in 1705 that the British astronomer Edmond Halley determined that the orbit of a comet that appeared in 1682 was the same as the orbit of two earlier comets that were observed in 1531 and 1607. He was the first to realize that these three comets were, in fact, three successive passages of the same comet, with a periodicity of about 76 years. He then predicted the return of the comet in 1758, a prediction that proved correct when the comet passed near the Sun in March 1759. In recognition of his work, the comet was given his name.
Physically, Halley’s comet nucleus (materialized by the round patch of fabric on the tactile image) is an elongated body. When it gets close to the Sun, the ice that makes up most of the nucleus begins to ‘vaporize’ and forms a “coma” (from the Latin word for “hair”) (materialized by glued-on sand on the tactile image). Even closer to the Sun, solar radiation pushes gas and dust particles out of the coma; these particles form a dust tail (materialized by glued-on sand extending from the coma on the tactile image) that can extend millions of kilometres into space. This tail is often curved because it takes the shape of the comet’s orbit. The gas can also be ionized by solar radiation, and the charged molecules and atoms then develop an “ion tail” (materialized by the straw on the tactile image) that is straighter than the dust tail and always directed in the direction opposite to the Sun.
:: Full Activity Description ::
Prior to the activity:
- Gather the children in groups of 5 elements – visually impaired and non-visually impaired (ideally 3 non-visually impaired to 2 visually impaired);
- Present one image per group;
- Distribute materials accordingly;
During the activity:
- Close supervision – follow each group and explain each of the tactile elements and their correspondence to the each object feature;
- Understand the different needs of each group of students to promote interaction between the children during the building of the tactile image – visually impaired children need to be familiarized with the different materials involved;
Building the tactile image:
Print image 013_Halley_Image and 013_Halley_Mold, in a regular black and white printer;
Cut the section on 013_Halley_Mold and with a pen outline the cut section on 013_Halley_Mold in the thick fabric;
Cut the thick fabric accordingly to the area outlined in 013_Halley_Mold;
Place abundant glue on the area that correspond to the inner side of the comet’s surface and place the fabric on top of the glue;
Place the thick fabric on top of the glue;
WAIT FOR THE IMAGE TO DRY.
Place glue in the curved areas around the thick fabric and place sand on top of the glue;
Place glue in the thick wavy areas correspondent of the upper tail and place sand on top of the glue;
Place glue in the thin wavy area corresponding to the lower tail and place sand on top of the glue;
WAIT FOR THE IMAGE TO DRY. IT MIGHT TAKE A WHILE BEFORE YOU CAN EXPLORE THE IMAGE.
:: Exploring the tactile image ::
There are several ways in which you can explore the scientific content of the tactile schematic images.
If you’re presenting the final tactile image to the children, first let them explore and feel the different textures. Questions will arise as the child explores and it is important to guide them. Read “The Scientist Explains” to understand the different features present in Halley’s schematic tactile image.
(1) Explore the shape of the comet; (2) the rocky nucleus represented by the thick fabric; (3) coma and (4) dust tail represented by sand and (5) straws representing the ion tail.