Activity
Using Tactile Graphics to Teach Students with Visual Impairments About Tidal Range
Through a tactile graphic and an active model, students will gain a better understanding of spring tide and neap tide.
Due to the combined gravitational effects of the Sun and Moon, extreme tidal ranges occur twice a month at the 2 times when the Sun, Moon, and Earth are lined up. However, when the Sun, Earth, and Moon are at 90 degree angles, smaller tidal ranges occur, called neap tides. Students will better understand that Spring and Neap tide are based on the tidal ranges and not just the level of the water at low and high tide through this tactile graphic and active model.
Related Vocabulary:
- tide – daily changes in the level of ocean water
- high tide – water level higher than average sea level
- low tide – water level lower than average sea level
- tidal range – difference between the level of ocean water at high tide and low tide
- tidal cycles – the periodic changes in the intensity of tides caused primarily by the varying relations between the Earth, Moon, and Sun.
- spring tide – greatest tidal range which occurs two times a month, at the new moon and full moon
- neap tide – tide of minimum range which occurs at the first and third quarters of the Moon.
Materials
- Draftsman and draftsman paper OR
- Large braille paper and Wikki Stix (See Figure 1.)
- Printed labels in appropriate font size or braille labels as follows:
- 2 sets of:
- high tide
- low tide
- 1 set of:
- Neap tide
- Spring tide
Preparation
Using Wikki Stix on a large piece of braille paper, create a tactile graphic describing neap tide and spring tide by using wikki stix to describe the low tide and high tide levels for each. For students who are more advanced, exact tide levels may be added, but this is not necessary. Show the low tide and high tide during spring tide as lower and higher than the low tide and high tide during neap tide. See picture
Apply labels in appropriate medium for high tide and low tide as well as labels for neap tide and spring tide.
Procedure
Modeling Neap Tide (Active Model)
Using your hand to model low tide and high tide, describe the difference between spring tide and neap tide as follows:
- Students will observe your hand tactually and/or visually as appropriate.
- Say, ” We will first model neap tide.”
- Have the student observe your hand as you hold it at table level.
- Say, “This represents the low tide during neap tide.” Ask the student what low tide is and discuss if needed.
- Then, (teacher) raise your hand to shoulder level.
- Say, “This represents high tide during neap tide.”Ask the student what high tide is and discuss if needed.
- Please consider the difference between the two tides. During Neap tide there is the least difference between low tide and high tide (tidal range)
- Repeat neap tide if necessary.
Modeling Spring Tide (Active Model)
- Have the student observe your hand as you hold it at about a foot below table level.
- Say, “This represents the low tide during neap tide.” Ask the student what low tide is and discuss if needed.
- Then, (teacher) raise your hand to above shoulder level,
- Say, “This represents high tide during spring tide.”Ask the student what high tide is and discuss if needed.
- Please consider the difference between the two tides – Discuss – During spring tide there is the greatest difference between low tide and high tide (tidal range)
- Repeat neap tide if necessary .
Tactile Graphic
- Use the graphic to reinforce the concepts that you have taught with the active model.
Variations
- As described, exact tide levels could be included in the tactile graphic if appropriate for the student.
- For more advanced students, print a table of recent tides or the past month at a location they are familiar with. Have students determine when neap tides and spring tides occurred.
NGSS Standards
Grade 5 – Space Systems
PS2.B: Types of Interactions
- The gravitational force of Earth acting on an object near Earth’s surface pulls that object toward the planet’s center. (5-PS2-1)
ESS1.B: Earth and the Solar System
- The orbits of Earth around the sun and of the moon around Earth, together with the rotation of Earth about an axis between its North and South poles, cause observable patterns. These include day and night; daily changes in the length and direction of shadows; and different positions of the sun, moon, and stars at different times of the day, month, and year. (5-ESS 1-2)
Middle School – Space Systems
ESS1.A: The Universe and Its Stars
- Patterns of the apparent motion of the sun, the moon, and stars in the sky can be observed, described, predicted, and explained with models. (MS-ESS1-1)
High School: Forces and Interactions
PS2.B: Types of Interactions
- Newton’s law of universal gravitation and Coulomb’s law provide the mathematical models to describe and predict the effects of gravitational and electrostatic forces between distant objects. (HS-PS2-4)
- Forces at a distance are explained by fields (gravitational, electric, and magnetic) permeating space that can transfer energy through space. Magnets or electric currents cause magnetic fields; electric charges or changing magnetic fields cause electric fields. (HS-PS2- 4),(HS-PS2-5)
By Laura Hospitál
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