When your summer calls for more science, try out one of our four favorite physical science experiments with your young scientists. And check out all our physical science supplies, equipment, and easy-to-use kits over at hBARSCI’s website!
An object’s density is calculated by dividing its mass (weight) by its volume (the amount of space it occupies). Liquids have density too. This experiment explores density in a fun (but potentially messy) way by creating a tower using a combination of several different types of liquid to determine which is more dense. Lighter liquids are less dense than heavier liquids so they float on top of them. Head outdoors with this list of liquids and show your young experimenters the magic of density!
Supplies: light corn syrup, concentrated dish soap (such as Dawn), water, vodka or other alcoholic spirit (substitute rubbing alcohol if desired but see note below*), canola oil, large jar or clear glass cylinder with tightly fitting lid, food coloring (optional, but super fun)
*If you have substituted rubbing alcohol for the spirits, the canola oil layer will go after the water layer, and the rubbing alcohol layer will be the final layer at the top of the density tower.
Steps:
Begin by pouring the light corn syrup into the bottom of the jar. The layer should be about an inch tall. Supervise scientists carefully—for younger folks, it might be best for the adult to do the pouring of the liquids.
If you wish to color the light corn syrup, add a few drops of food coloring now, and stir with a fork or other object.
Next, pour the dish soap into the jar to layer on top of the oil. For best results, each time you pour a new liquid into the jar, tip the jar to the side slightly and pour the liquid down the inside wall of the jar. Alternatively, use a turkey baster to put the liquid into the jar, again pouring the liquid down the inside wall. This will keep the liquids you are pouring in from disturbing the liquids already in the density tower.
Mix a few drops of blue food coloring into some water and pour it into the jar. This will form your third layer.
Add a few drops of food coloring to your clear vodka or other alcoholic spirit. Pour the alcohol into the jar to create the fourth layer (see note above if swapping out the spirit for rubbing alcohol*).
Top off the density tower with canola oil. You can color this with food coloring too if you wish.
Place the lid tightly on the jar, so that none of the contents will leak out.
Let kids have fun tipping the jar upside down and on its side, and then watch as the layers of the tower separate themselves once the jar has been placed face up again on a flat surface. Do not shake the jar, as this may cause some of the layers to combine.
Suggestions for more science: Carefully drop a couple of small objects into the mixture and observe what happens. Can you find an object to float on each layer? Objects and liquids float on liquids of a higher density and sink through liquids of lower density.
Facing a rainy day? No problem. Grab some marshmallows, straws, and your kids’ imaginations, and see what you can build!
Supplies: marshmallows (normal size), plastic drinking straws, scissors (to be used with adult supervision only), ruler (if desired)
Steps:
Start off by walking your scientists through the difference between 2D and 3D shapes, asking them to first build a 2D shape and then make that 2D shape 3D. Allow them to cut the straws to customize the size and shape of their structure.
Next, suggest that they explore different shapes, both 2D and 3D. Which shape do they think will be the most stable or able to bear the most weight?
Suggest a goal of creating a marshmallow and straw tower that is at least 6 inches tall from base to top. Based on their previous experimentation with the marshmallows and straws, what configuration of the two will help the tower be the most sturdy? Use the ruler to measure the towers as you go along.
Ask them what other types of structures they can build. As they work, encourage them to “try something different” as they encounter problems with their structures.
Additional suggestions: Try building a two- or three-story structure, creating a marshmallow bridge, building a structure using only one shape, or creating a structure that can hold a piece of paper.
Questions to consider while building: What happens when you use a square base versus a triangle base? What happens as the tower gets taller? What happens when you use shorter pieces of straw versus longer ones? Do you have any other materials around the house you could use to strengthen your structures?
Suggestion for more science: Try adding a challenge by creating your tower for a specific purpose. Can you make a tower that holds an egg six inches off the table? How about a book?
Making sorbet is actually quite easy and a good workout for the arms! This sorbet in a bag science experiment is a fun activity to try at home or in the classroom. It does require some adult supervision and assistance. A good pair of gloves are needed as this science activity does get very cold.It’s summer, and we love all things sweet and cold. Instead of heading to the local dairy bar, grab a few simple ingredients and head outdoors. Kids can learn just how sorbet is made . . . with chemistry!
Supplies: apple juice (2 cups), ice (2 cups), salt (1 cup), water (1 cup), food coloring (optional), 1 gallon-sized zip-seal bag, 2 quart-sized zip-seal bags
Steps:
Pour 1 cup of apple juice into a quart-sized zip-seal bag. Add 8 drops of food coloring into the first bag if desired.
Pour the other cup of apple juice into the other quart-sized zip-seal bag. Add 8 drops of blue food coloring into the second bag if desired.
Place the 2 cups of ice, 1 cup of water, and 1 cup of salt into the gallon-size bag.
Make sure to tightly seal the smaller bags and place them both into the larger bag. Shake vigorously for 3 to 5 minutes. Note: The bag becomes much too cold to handle bare-handed, so please make sure you have a good pair of gloves to shake it with—take care if working with younger scientists.
Remove inner bags, scoop out and serve.
In order to make your homemade sorbet, your ingredients need to get very cold and freeze. Instead of placing the ingredients in the freezer, you mix together salt and ice to make a solution. Adding salt to the ice lowers the temperature at which water freezes. Shaking the bag allows the juice mixture to move around to allow for better freezing.
One other cool fun fact about sorbet: Sorbet changes its state of matter: It starts out as a liquid but changes to a solid as it freezes—then it goes back to a liquid when it melts!
Set up a quick and easy bubble station in your yard using items you already have at home. If you’re able to follow the DIY homemade bubble recipe below, the "secret" ingredient will not only get you strong bubbles but giant bubbles! And you can compare this recipe with any mixture of soap and water to see how the resulting bubbles differ in strength, size, etc.
Supplies for “secret” bubble recipe: water (6 cups; distilled works best), dish soap, glycerine or corn syrup, bubble wand or straw
Steps:
Measure 6 cups of water into one container, then pour 1 cup of dish soap into the water and slowly stir it until the soap is mixed in. Try not to let foam or bubbles form while you stir.
Measure 1 tablespoon of glycerin or 1/4 cup of corn syrup and add it to the container. Stir the solution until it is mixed together. You can use the solution right away, but to make even better bubbles, put the lid on the container and let your super bubble solution sit overnight. (Note: If you use "Ultra" dish soap, double the amount of glycerin or corn syrup.)
Dip a bubble wand or straw into the mixture, slowly pull it out, wait a few seconds, and then blow. How big of a bubble can you make? How many bubbles can you make in one breath?
Other supplies for bubble station: bubble wand or straw(s); plastic bottles; cookie cutters; a jug, a sock, and a hair tie or rubber band to make a bubble snake; tub, pie plate, or other container for bubble solution (make a lot and use multiple containers).
Suggestion for more science: Learn about surface tension! How does dish soap break surface tension? Grab a couple glasses and find out! Put a glass of water in the center of a pie plate. Slowly pour some water from the second glass into the first glass until it is very full and the water forms a dome above the rim of the first glass. Set the glass with less water aside. Carefully stick your finger straight down through the dome of the water in the full glass and watch what happens. Next, put a small drop of dish soap on the tip of your finger and do the exact same thing—stick the finger with soap on it straight down through the dome of water. This time what happens?
Look no further than our collection of physical science equipment, supplies, and kits over at the hBARSCI website!
