Featured in PASCO’s College Biology Instructor Guide

College Biology Instructor Guide


College Instructor edition with 26 experiments covering introductory and general biology topics.

Surface Area to Volume

Lab Summary

Use a PASCO quad temperature sensor and ice bath to explore the relationship between the inner volume of a citrus fruit and its outer surface area.


In this activity, students investigate how a cell’s surface area to volume ratio affects the way the cell responds to the environment. To learn this, students:

  • Use citrus fruits as a model to investigate how the surface area to volume ratio influences the way a cell interacts with its environment.
  • Calculate the mathematical relationship between surface area and volume.
  • Apply the concept of surface area to volume ratios to biological systems.


In this lab, students will gain experience in the following procedures:

  • Measure the circumference of two or three different citrus fruits.
  • Calculate the radius, surface area, volume, and the ratio of surface area to volume of each fruit.
  • Place the fruits in an ice-water bath, and record how quickly each fruit releases heat into its environment.

Sensors / Equipment Used:

PASPORT Quad Temperature Sensor


Allows any combination of our stainless steel, fast response or skin/surface temperature probes for a wide variety of temperature measurement. For use with PASPORT Interfaces.

Materials Used:

Citrus fruits, varying type and size - 2
Dissecting probe or pin
Ice and water - 2 to 3 liters
Labeling marker
Labeling tape
Metric ruler
Petroleum jelly - 1 g
Polystyrene cooler, plastic bucket or other
vessel for ice bath
Twine or string - 20 to 30 cm

The Associated Bundle:

College Biology Bundle


A complete probeware bundle designed for PASCO's College Biology curriculum

Interface Required

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