Physics and Astronomy

Heavy Engineering
INDYcator 500

To determine the pH of some unknown liquids.

Participants Teams of up to six..

Each team will be issued with dropping bottles of solutions adjusted to known pH values of 1, 3, 5, 7, 9, 11, 13. They will also be issued with dropping bottles of indicators: bromthymol blue, phenolphthalein, alizarin yellow, orange IV, bromcresol green, bromphenol blue and methyl red. The teams will also be given two sheets of clear plastic (acetate sheets) on which they can do spot tests. Plain paper will be provided for an underlay.


The event will involve an analytical race. Each team will be given three unknowns for which they are to determine the pH as precisely as possible. They must first determine the color change ranges of the indicators and then use the indicators wisely to zero in on the closest pH.

The teams will be issued with a sheet of paper with the three unknowns named. They will fill in their results on this sheet and form a line at the judging table. If the analysis is incorrect, the judge will mark which unknowns are correct and which are incorrect and send the team back to correct their error.

FAQ Q1. How can I obtain pH buffers 1 and 13?
A1: Used a recipe form the CRC Handbook "Buffer Solutions: Giving Round Values of pH at 25C
For pH 1 use 25 mL of 0.2 M KCl and 67 ml of 0.2 M HCl
For pH 13 use 25 mL of 0.2 M KCl and 66 mL of 0.2 M NaOH

The teams will be assigned points based on their relative time of accomplishing the analysis.
Points will be deducted for the following:

  • each group member who is unprepared (eg is without SAFETY GLASSES)
  • unsafe laboratory procedures.
  • improper lab station clean up.
  • improper dispoosal procedures.
Dress Code

Students who do not meet the dress code will not be allowed to participate. Students must:

  • wear long pants
  • have no exposed midriffs
  • have socks and shoes that completely cover their feet.

The University safety policy, devised by Occupational Health and Safety, mandates “maximal skin coverage” for all laboratory personnel, including students. Ankle-length pants and socks that cover the ankle are required. No shorts or capris are permitted. Exposed midriffs are not allowed. Long hair must be tied back. Shoes must completely cover your feet: toes, sides, heel and the entire upper foot. Running shoes are generally acceptable. Sandals, open-toed shoes, ballerina shoes, open-top shoes, and shoes with cut-outs or openings are not acceptable.

Safety glasses will be provided. Make sure you wear safety glasses at all times in the laboratory.

Read and understand all instructions prior to starting the procedure. If you do not understand anything ask the supervisor.

If you spill any materials or break glassware contact the supervisor before attempting a cleanup.

Do not carry out unauthorized experiments.

Source Technical University of Nova Scotia

Events | Location | Scheduling | Registration | Participants | Committee | Judges and Officials | Scoring | Awards | Media
Contact Us | Our Sponsors | Faculty of Science | Western

© 2001 The University of Western Ontario,
Department of Physics and Astronomy

Webmaster: Patrick Whippey
Site Design: Julie Whitehead