Use of an Adapted Simple Balance

By Laura Hospitál on Apr 14, 2015

Purpose

To teach students who are visually impaired to use an adapted balance scale

Background

The use of the balance scale is usually taught in elementary school  This tool can be difficult for students with visual impairments to utilize without adaptation.  However, it can be easily adapted so that a student with a visual impairment can not only record measurements in your class but also be involved in taking measurements and learn more fully the manner in which a balance scale operates.

Preparation:

Balance: Cut a piece of Wikki Stix (www.wikkistix.com) about 2” long.  Stick the piece of Wikki Stix to the balance at the center mark straight up and down so that it comes down at least 1” under the balance marker (arrow) when it points straight down. (See picture on the left).  These meaurements may vary depending on the balance used. 

Some balances have a significantly raised line at the center mark.  If this is the case, then the balance will not need to be adapted. 

Standard Masses:  Label the standard mass set in braille and large print on the sides next to the various size standard masses.  When there are two of one size standard mass, place the label in the middle of the two.

Label individual standard masses, 5g, 10g, and 20g, with both braille and large print labels. (See picture on the right.)  The color of these standard masses may also be used to differentiate them by students with low vision.  (See picture on the right.)

Close up picture of the center mark and wikki stix linePictures of 1g, 5g, 10g, and 20g weights

Materials

  • 1 Piece of Wikki Stix
  • Braille label paper 
  • Balance scale (us.ohaus.com)  - Either the primer balance or school balance
  • Standard mass set (www.enasco.com)
  • Set of gram weights of 1g, 5g, 10g, and 20g

Procedure

  1. Place the object of unknown mass in the tray on the right of the balance.  Explain to the student that either tray could be used but in order to avoid confusion we will always place the object in the right hand tray
  2. Choose a standard mass (weight) which seems close to the mass of the object.
  3. Place this standard mass on the left-hand tray.
  4. Wait 15 seconds for the arrow to stop swinging. 
  5. To determine if balanced:  ​
    • Place hand upside down on the lab table.
    • Slowly move hand toward the indicator (Wikki Stix or raised line) Some assistance may be necessary at first.
    • Find the indicator with the middle finger.
    • Move up the indicator with the finger slowly being careful not to move push the arrow to one side or the other.
    • Determine if the balance mark (swinging arrow) is to the left or to the right
    • If it is to the left, then the object in the right hand tray is heavier so add more standard masses.
    • If it is to the right, then the standard masses are heavier, so remove one at a time, starting with the smallest standard mass.
    • Each time a standard mass is added or removed, wait 15 seconds for the arrow to stop swinging.
    • Once the arrow is in the center, the mass of the unknown object in the right tray equals the mass of the standard masses in the left tray.
    • Remove the standard masses and carefully count them twice to determine mass before replacing them to the set.
    • Record the mass of the object in grams (g).

NGSS Standards:

Standard units are used to measure and describe physical quantities such as weight, time, temperature, and volume.

(5-PSI-2 and 5-PSI-3)

Adapting a simple balance for students who are blind or visually impaired

Read more about: Science Adaptations, Science, STEM