Featured in PASCO’s Biology through Inquiry Teacher Guide

Biology through Inquiry Teacher Guide

(PS-2870C)

Features 25 inquiry based labs covering the fundamental concepts of cell biology, ecology and physiology.

Buffers in Biological Systems

Lab Summary

Use a pH sensor to determine which solution is the best buffer.

Theory

In this activity, students examine the role that buffer solutions have on the ability to balance the pH homeostasis. Students:

  • Determine the pH change when they mix an acid with water.
  • Determine the pH change when they mix an acid with club soda, which is a buffered salt solution.
  • Determine which solution is the best buffer.

Method

Students will gain experience conducting the following procedures:

  • Use the pH Sensor to measure the change in pH in water and in club soda when they add an acid to them.
  • Compare the change in pH of water and club soda.

Sensors / Equipment Used:

PASPORT pH Sensor

(PS-2102)

Has a wide measurement range of 0 to 14 pH. Has a resolution of 0.01 pH. For use with PASPORT Interfaces.

Magnetic Stirrer

(SE-7700)

A "must-have" piece of lab equipment when doing titration experiments.

Buret Clamp

(SE-9446)

The V-shaped, plastic-coated jaws will gently hold a buret and lock at any angle.

Base and Support Rod

(ME-9355)

The Large Base and Support Rod includes built-in leveling screws and an aluminum rod that is 12.7 mm (1/2 in.) in diameter and 45 cm long.

Materials Used:

Graduated cylinder, 10-mL

Beakers (3), 250-mL

Club Soda, 200-mL

Vinegar, 5% acetic acid, 20 mL

Wash Bottle

Distilled Water, 1 L

The Associated Bundle:

Biology Standard Sensor Bundle

(PS-2925A)

The Biology Standard Sensor Bundle includes a photosynthesis tank and the sensors required to perform 19 of the 24 Lab Activities in the Biology through Inquiry manual.

Interface Required

This experiment may require software and an interface for data collection.