:: 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 planet Earth and correspondent suggested textures:
- Thin wire;
- Aluminum foil;
- Thick fabric;
- Black and white prints of image (x2) and mold (x1). Click links to Download.
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 ::
Earth is our home and the third planet from the Sun, with a mean distance of about 150 million kilometres. This distance is such that the average surface temperature is above the freezing point of water (0°C) and liquid water can exist freely. This played a fundamental role in the development of life on our planet, contrary to Venus and Mars, which have surface temperatures either much warmer or much colder.
The shape of the Earth is very close to a sphere. Because of its slow rotation — once every 24 h — the distortions due to its rotation are small, the difference between the equatorial radius (6,378 km) and the polar radius (6,357 km) being only 21 km. Earth only has one natural satellite, the Moon, which is thought to have played a major role in stabilizing the axis of rotation of the Earth. Once again, this may have been a favourable element in the emergence of life.
[While you explore the tactile schematic image you can find: ]
Liquid water, continents and polar caps
On Earth, 71% of the surface is covered by liquid water (materialized by plastic on the tactile image), so the area occupied by seas and oceans is more than twice that occupied by land. The distribution of lands and seas is unequal and peculiar: land masses are in majority located in the Northern hemisphere, with three major continents: Europe, Asia, and North America (continents are materialized by the thick fabric on the tactile image). The poles of the Earth are also quite different: there is an ice-covered continent at the South Pole (Antarctica), but an ocean at the North Pole (the Arctic Ocean), which forms an ice cap in winter (both materialized by the aluminium foil on the tactile image).
On Earth, surface elevations are measured with respect to the mean sea level. They vary between a height of 8,848 m (Mount Everest) and a depth of 11,000 m (the Mariana Trench in the northwest part of the Pacific Ocean). The average depth of the oceans is 3,800 m, and the average altitude of lands is 840 m.
Clouds and hurricanes
Earth has a relatively thin atmosphere extending to less than 200 km altitude. Dry air is mainly composed of nitrogen (N2: 78.08%), oxygen (O2: 20.95%), and argon (Ar: 0.93%). The remaining 0.04% is a mixture of “trace” gases, mostly carbon dioxide (CO2), but also rare gases such as neon (Ne), helium (He), and krypton (Kr). On average, water vapour (H2O) accounts for 0.25% of the mass of the atmosphere, but its concentration varies a lot depending on the local temperature: it can be anywhere between 0.01% and 5%. When lifted in the upper parts of the atmosphere (above 3000 m on average), water vapour condenses to form clouds of very diverse densities and shapes (materialized by clumps of cotton on the tactile image); some of these clouds can develop into powerful hurricanes over the oceans (materialized by curled wire and cotton on the tactile image).
The climate of the Earth is presently undergoing a warming phase due to the action of “greenhouse gases”, such as carbon dioxide and methane that are being released in large quantity since the beginning of the industrial era. These gases tend to trap infrared radiation from the surface, like the roof of a greenhouse.
:: Activity Description ::
Prior to the activity:
- Gather the children in groups of 3 to 5 elements – visually impaired and non-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:
:: STEP 1 ::
Print two copies of 04_Earth_Image.pdf, in a regular black and white printer;
:: STEP 2 ::
Place the plastic on top of the paper mold and with a pen outline the shape of the cut image;
:: STEP 3 ::
Cut the plastic according to the drawn section;
:: STEP 4 ::
Place abundant glue on top of the 04_Earth_Image.pdf area correspondent to the cut area;
:: STEP 5 ::
Place the plastic on top of the glue;
:: STEP 6 ::
Cut the shape Earth’s continents on 04_Earth_Mold.pdf;
:: STEP 7 ::
With a pen outline it on top of the thick fabric used for continents;
:: STEP 8 ::
Cut the fabric;
:: STEP 9 ::
Place glue on top of it;
:: STEP 10 ::
Glue the thick cut section accordingly;
:: STEP 11 ::
Cut the shape of the polar caps on 04_Earth_Mold.pdf;
:: STEP 12 ::
With a pen outline the polar caps shape in the thick fabric used for continents;
:: STEP 13 ::
Cut the fabric;
:: STEP 14 ::
Wrap the aluminum foil accordingly to the cut areas;
:: STEP 15 ::
Glue the aluminum foil on top of the correspondent polar caps;
:: STEP 14 ::
Curl the cotton around the wire to produce the hurricane feature;
:: STEP 15 ::
Curl both textures alike in the size of the round shape of the hurricane;
:: STEP 16 ::
Place abundant glue to the round shaped area;
:: STEP 17 ::
Glue it in place;
:: STEP 18 ::
Place abundant glue on the region denoted by a curved line;
:: STEP 19 ::
Place cotton on top of the glue;
Wait for the image to dry. This may take a while.
:: 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 Earth’s schematic tactile image.
(1) The presence of water is represented by plastic texture; (2) The continents are represented by the thick fabric; (3) the polar caps by aluminium foil; (4) clouds and (5) hurricanes.