With school closings likely continuing for the rest of this academic year, Lawrence Technological University is offering some science experiments to help keep kids’ minds engaged at home.
Teachers looking for demonstrations to share remotely can also use these two experiments.
The experiments can be done with materials found in most homes, according to the university in Southfield.
ELEPHANT TOOTHPASTE REACTION
You will need the following items: a 12-ounce water bottle, one-half cup of 3% hydrogen peroxide, liquid dish soap, 3 tablespoons of warm water, one-quarter ounce of active dry yeast (fast-acting is best for effect), a plastic or glass bowl, a spoon, a baking pan and food dye.
- Place a large baking pan or tray on a table that is a comfortable height for you to work on.
- Stand a water bottle upright in the middle of the baking pan.
- Measure one-half cup of 3% hydrogen peroxide and add the hydrogen peroxide to the bottle.
- Add a few drops of food coloring and swirl to mix.
- Add a few drops of dish soap and swirl again. Set the bottle aside while you prepare the yeast mixture.
- In the bowl, add the yeast and 3 tablespoons of warm water.
- Mix the yeast and water together by stirring with a spoon.
- Quickly add the yeast mixture to the bottle, step back, and observe.
If multiple people are able to participate, have each person do this experiment at the same time using different colors of food dye.
You should see a display of colorful foam bursting out of the top of the water bottle. But what exactly is the science behind what is happening here? You witnessed the hydrogen peroxide breaking down into water and oxygen – something that happens naturally, but very gradually.
You are speeding this decomposition process up with the addition of the yeast, which acts as a catalyst when added to the solution. A catalyst is a substance that has the ability to “speed up” a reaction. When this yeast catalyst is added, the hydrogen peroxide quickly breaks down into water and oxygen, and the oxygen is trapped in the form of soap bubbles.
It is that quick release of oxygen that causes the foam to expand so quickly and burst dramatically out of the top of the water bottle. Some say the visual effect of the colorful foam bursting out of the water bottle resembles larger sized toothpaste being squeezed out of its container—the origin of the name “Elephant Toothpaste”..
MAKE A LAVA LAMP
You will need a 12-ounce water bottle, water, vegetable or canola oil, food dye and one Alka Seltzer tablet.
- Fill the water bottle a little more than half full with vegetable oil.
- Fill the rest of the bottle with water (almost to the top but not overflowing). Wait until the liquids settle—what do you notice about the order of the liquids?
- Add about 10 drops of food coloring. Make sure to add enough so the water becomes fairly dark in color. What is the difference between the way the food dye behaves in vegetable oil and the way that it behaves in water?
- Break an Alka Seltzer tablet into four pieces. Drop one of the pieces into the bottle and observe. When the bubbling stops, add another piece. Repeat for the rest of the Alka Seltzer. What do you see happening?
- Once all of the Alka Seltzer has been dropped into the bottle and the bubbling has completely stopped, screw the cap tightly onto the bottle.
Take it a step further and shine a light through the bottom of the bottle for extra visual effect.
One of the scientific concepts you can observe in this demonstration is density. Even though the vegetable oil is added to the bottle first, the water sinks underneath the oil. This is because oil is less dense than water, and oil is therefore able to “float” on top of the water, said Jaclyn Smith, outreach coordinator at LTU’s Marburger STEM Center. The center does outreach for K-12 students in science, technology, engineering and mathematics.
Other concepts highlighted are polarity and solubility. When the food dye is added, it is able to dissolve in the water because it is water-based, and like water, it is a polar substance—its atoms are arranged so that they have magnetic poles, one end positive, the other negative.
Oil, on the other hand, is a non-polar substance, so the dye cannot dissolve in it—you will see it travel through the oil as perfectly round droplets of color.
Finally, when the Alka Seltzer tablet is dropped into the bottle, a chemical reaction happens within the water which produces carbon dioxide and water bubbles, which float up through the oil and simulate the visual effects of a lava lamp.
After the experiments, ask your kids how they can expand upon these concepts. What questions do they have about the content and how do they see it relating to their everyday lives? How can they share what they have learned with others?
You could have them do the experiment on their own and record it as an informational video that they could share online. They could do the experiment again and use a slow-motion camera to try to get a closer look at the phenomenon.
They could record the experiment and incorporate it into a Tik-Tok video. Try to find creative ways to engage their young minds by using technology that interests them.
Here are some additional resources:
Bozeman Science (6-12) – YouTube channel with short science video lectures.
Discovery Education (K-12) – Online videos and lesson activities.
HHMI BioInteractive (9-12) – Resources geared toward the biological sciences.
National Geographic (K-12) – Find educational resources for Grades Pre-K–12, from brief activity ideas to multimedia lessons and units.
WeatherSTEM (K-12) – Scholar from WeatherSTEM resources and lessons engage students in weather and data literacy.
Exploratorium Museum (K-12) – For all ages, in both formal and informal learning settings, these essential tools spark curiosity, exploration, and understanding.
Scientific American (K-12) – Fun science activities that can be done with household items in a half hour or less.
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