Design Challenge: Beetroot Experiment

Beetroots are root vegetables that appear red because the vacuoles in their cells contain a water-soluble red pigment called Betalain. These pigment molecules are too large to pass through membranes. Today we are going to explore the effects of different temperatures on the permeability of beetroot cell membranes.

Carry out beetroot pigment extraction under different temperatures in different test tubes and observe the effect of temperatures on the color of solutions in each test tube. Conclude the effect of temperature on the permeability of beetroot cell membranes.

List of materials per person

• 1 beetroot
• 1 cork borer or otherwise a knife to cut the pieces
• 4 conical tubes with lid (15 ml would be great otherwise 50 ml)
• 5 test tube holders or otherwise some containers like plastic cups to place the tubes
• Thermometer
• 10-20 ml syringe
• Ruler
• Sharpie
• Pen
• Paper to take notes of observations such as size of beetroot, temperature, etc
• Paper towel to dry the beetroot pieces and to clean up
• Some containers to place the conical tubes as they don’t stand alone

As a team

• Distilled water 1-2 gallons
• Crushed ice
• 4 large containers (enough for each kid’s 4 samples): 1 for an ice bath, 1 for room temperature bath, 2 for 2 different hot temperature baths
• Depending on time, we might need to have pieces of beetroot ready beforehand

• Prepare 4 water baths pre-set to a range of temperatures between 0 °C and 100 °C (this should be done by adults)
• Use a syringe to add 10 ml of distilled water to all tubes. Label each test tube with a temperature from the pre-set range
• Place each tube in the water bath set to the corresponding temperature for 5 minutes
• Check the temperature of each bath is correct using a thermometer. It is unlikely to be exactly the desired temperature. Record the actual temperature
• Cut 4 beetroot cylinders using a cork borer. Using a knife and ruler, trim them all to the same length (1 cm is sufficient). Wash the cylinders thoroughly with water until the water runs clear and pat dry gently with a paper towel
• Add one beetroot cylinder to each of the eight tubes and leave in the water bath for 15 minutes
• Finally, take the tubes out of the bath and observe each tube

• Use the Design Challenge Handout to guide your design process.