Hydrogen peroxide (be sure to use 3 %, the kind sold for home use in pharmacies)
Tablespoon and teaspoon-sized measuring spoons
Liquid measuring cup
Three clear containers, such as glasses or plastic cups
Stirring rods or spoons
Sharpie marker, tape or other materials to label the containers
1. Label the containers: A) hydrogen peroxide + iodized salt, B) hydrogen-peroxide + non-iodized salt, and C) water + iodized salt.
2. Measure 100 mL (about 1/3 cup) of water and add it to container C. Measure 100 mL (about 1/3 cup) hydrogen peroxide (3%) and add it to container A. Next measure 100 mL (about 1/3 cup) hydrogen peroxide (3%) and add it to container B.
3. Add two Tablespoons of iodized salt to container A and stir. Add two Tablespoons of iodized salt to container C and stir. Add two Tablespoons of non-iodized salt to container B and stir.
4. Observe the containers for a few minutes. Record any changes that occur.
Check our iodine chemistry post to see what iodine looks like in water or hydrogen peroxide. Do you see anything that looks similar?
5. Now add 1/2 teaspoon of cornstarch to each container. What happens?
I love this reaction! It is quick and fairly easy to understand. Let me know if you have any questions about procedures or results.
2. Studying Density: Table Salt versus Salt Sense®
According to the label of the product, Salt Sense® contains real salt, but there is “33% less sodium per teaspoon.” How is this possible?
Prior to starting, answer the following questions:
What do you know about salt and its structure? How might the company achieve its claim of 33% less sodium per teaspoon? Is there 33% less chloride as well?
Iodized Table Salt
Iodized Salt Sense® (Available in grocery stores and online)
Microscope or hand lens
Petri dishes or similar shallow, clear containers
Measuring beakers or graduated cylinders
Kitchen scale that can weigh grams
Laboratory notebook or paper
Pen for recording results
1. Place a small sample of table salt in one petri dish and a sample of Salt Sense® in a second petri dish. Look at the samples under the microscope.
Draw what you see for each sample. How might the differences you observe change the amount of sodium per teaspoon?
2. Calculate the density of each substance.
Density = mass/volume
where mass is the weight of the salt in grams and volume is the amount of salt in mL.
Tare a measuring beaker on the scale (ask the instructor or read the manual if you don’t know what “tare” means.)
Pour 20 mL of table salt in the beaker. Weigh the table salt in grams and record the weight.
Now tare the second beaker. Add 20 mL of Salt Sense® to the beaker and weigh it. Record the weight in grams.
Calculate the density of each sample. Which sample is less dense? How much less dense is it?
How might you make your results more accurate?
Manufacturer Diamond Crystal’s explanation of Salt Sense®