How to Change a Liquid's Color From Yellow to Clear to Blue

The final result of this solution should be a liquid that appears dark blue like this.

The science of chemistry allows people to create amazing things from super strong plastics to heat-resistant putty, but it can also be used to perform magic...scientific magic at least. You can impress your friends or your children with this fairly simple experiment that turns a liquid's color from yellow to clear to blue. The experiment is called a Briggs-Rauscher reaction.

Things You'll Need

• Roll of heavy-duty plastic lining or tarp
• Safety goggles
• Thick rubber gloves
• 4 beakers or glass containers, 1-liter capacity
• Large glass pipette
• Large glass stirrer
• 410 mL 30% hydrogen peroxide
• 1 gallon distilled water
• 43 g potassium iodate
• 4.3 mL sulfuric acid
• 16 g malonic acid
• 3.4 g manganese sulfate monohydrate
• 4 g Vitex or other soluble starch
• 3 beakers or glass containers, 1-pint capacity
• Stirring plate
• Magnetic stirring bar

Instructions

Preparing the Experiment

1. Cover the surface of your work area with the large plastic covering, if you are performing this experiment in a carpeted room or other area where furniture can be damaged.

2. Put on your goggles and gloves, as you will be working with volatile and corrosive chemicals. Make sure you are working in a well-ventilated area.

3. Place the 410 mL of hydrogen peroxide into one of the large beakers using the glass pipette. Add enough distilled water to bring the solution to one liter. Set this beaker aside as solution A.

4. Place the 43 g of potassium iodate in the second large beaker and add 800 mL of distilled water. Add the sulfuric acid and stir the mixture until the iodate is completely dissolved. Add enough water to bring this mixture to one liter. Set this beaker aside as solution B.

5. Place the 16 g of malonic acid and the 3.4 g of manganese sulfate monohydrate in the third large beaker and add 500 mL of distilled water. Mix the Vitex starch with 55 mL of hot distilled water (heated carefully in a microwave) until the starch is completely dissolved. Add this mixture to the large beaker, then add enough water to bring this mixture to one liter. Stir the entire solution vigorously until it is completely clear. Set this beaker aside as solution C.

Performing the Experiment

1. Place the fourth empty beaker on top of the magnetic stirrer.

2. Using the three smaller beakers, add 150 mL of each of the three solutions to the large beaker. The order in which the solutions are poured does not matter.

3. Add the stirring bar and turn on the magnetic stirrer.

4. Observe the reaction. The liquid should cycle between yellow/amber, clear and dark blue for several minutes.

Tips & Warnings

• The color-changing effect of this experiment is due to the continual production and breakdown of the iodine and starch in the solution.

• You may invite others to assist you with this activity, but all participants should wear gloves and goggles.

References

• Thinkquest.org: Briggs-Rauscher reaction
• ScienceinSchool.org: Briggs-Rauscher reaction