Not only are STEM activities great fun for kids, but they’re also educational. Best of all, they don’t necessarily require special supplies. Grab your pretend lab coat and start growing some beautiful crystals with the following science experiment from Mad Science of Washington, D.C.
Crystal Star Ornament
What you need:
• Table salt
• Measuring cup
• Pipe cleaners
• Cookie cutter (simple shape
like a star or snowflake)
• Optional: food coloring
What you do:
- Twist your pipe cleaner into a simple star shape using a cookie cutter as a guide to bend the pipe cleaner around. Twist another pipe cleaner around it to make a handle.
- Measure 1 cup of warm tap water and pour it into a bowl.
- Add ½ cup of salt to the warm water and stir until it is almost dissolved; some salt will be left at the bottom of the bowl. This process should take about 3 to 5 minutes. You have just made a saturated salt solution.
- Pour some of your solution onto a plate. It should cover the bottom of the plate. If you add too much, the solution will take longer for your crystals to appear.
- Lay your star pipe cleaner shape in the salt solution on the plate. Sprinkle some salt over the ornament. By doing this, you are adding “seed crystals” that will help more crystals form.
- Leave the material to absorb the solution for 48 hours. You should see some crystals starting to form on the pipe cleaner. The longer you leave it, the more crystals will grow. Hang the pipe cleaner to dry completely. Enjoy your crystal ornament.
Now try this:
You can add a few drops of food coloring to your salt solution to make colored crystals.
What’s going on:
By adding salt to the warm water and stirring until no more salt dissolves, you have created a saturated salt solution. You have reached something called the maximum solubility point for salt in water. At the temperature and air pressure conditions in which you are doing your experiment, you can’t add any more salt to the solution.
By adding grains of salt or “seed crystals” to the pipe cleaner, you are providing the salt molecules in the solution with something to “grab onto.” This action lets them form longer crystals as the water evaporates out of the solution that you made, resulting in some lovely crystals on your ornament. Ice crystals can be seeded and formed in the same way as salt crystals—that’s why they look similarly festive!
Snowflakes are actually ice crystals which are formed high up in the clouds when water freezes. They always have six sides, but every single one of them is unique.
Many sandy beaches are made up of billions of broken quartz crystals. Quartz is a common mineral found in rocks, soil and sand.
Andrea Gibble of Club SciKidz MD offers some of the following fun science experiments parents and kids can do together.
Fun in the Sun with Shadows
Shadows are something that we see almost every day, but we usually don’t think about all of the science involved in them.
Shadows are made by blocking light. Light rays travel from a source in straight lines. If an opaque (solid) object gets in the way, it stops light rays from traveling through it. Throughout the day as the sun rises, moves through the sky and sets, shadows go from big to small and back again. They can also change directions in the middle of the day. The size and shape of a shadow depend on the position and size of the light source compared to the object.
Try it at home: Grab some sidewalk chalk and head to a sidewalk, driveway or parking lot. Find a spot you like that is fairly open and draw a star. You will stand in this spot. Stand on the star and have someone trace your shadow with a piece of sidewalk chalk. Write the current time inside of the outline. You are done for now.
A few hours later, stand on the same star again. Have someone use a different color of sidewalk chalk and trace your shadow. Write the time inside the outline. Were the two shadows the same? How were they different? What do you think would happen if you came outside and did this activity one or two more times?
Bend That Light!
Light moves in a straight line. It doesn’t turn corners or bend around circles. If the object is solid, the light will hit it and stop. If the object, such as water, isn’t solid, the light will travel through the object.
As the light passes from one material to another, it bends. Light rays bend because they travel faster through air than other materials like water. When the light rays hit the water, they slow down and bend inward, a phenomenon called refraction.
Try it at home: Fill a clear glass with water. Set the glass of water on a table. Gather one or two pieces of paper and a marker. Fold the paper in fourths. Cut or rip the paper into fourths so that you have four equal-sized pieces.
Write the word hello on one of the pieces. Take the piece of paper and set it behind the glass of water, with the words facing the glass. Go to the other side of the table and read what’s on the paper through the glass. Can you still read the word? What happened to the word?
Try again, but this time, draw a picture on one of the pieces of paper. Put the paper behind the glass. Go to the other side of the table and look at your picture. What happened to it?
While standing in front of the glass, reach around and hold the piece of paper behind the glass while still looking through the glass. What happens as you move it back and forth or side to side?
Salt Lava Lamp
Pretend you are at a water fountain. What will happen if you throw a penny in the fountain? You’re right! It will sink. The penny will sink because it is denser than water. What would happen if you tossed a rubber duck into the fountain? Right again! It would float. The rubber duck floats because it’s less dense than water.
One more question: What if you poured oil in the fountain? It would float because it’s hydrophobic. This word literally means “fear of water.” Instead of the oil molecules being attracted to the water molecules, they actually repel them.
Try it at home: You’ll need a clear glass jar filled about two-thirds full with water, food coloring, oil (vegetable works well) and salt (regular table salt works best).
First, tint the water in the jar a different color. Choose any color except for yellow. Once your color is well mixed into the water, slowly pour some vegetable oil into the jar. Leave about an inch open at the top of the jar.
As you pour the oil into the jar, it may fall down into the water, but you will see that it quickly separates and rises to the top, sitting on top of the water. The oil is hydrophobic. As you saw when you poured the oil into the water, even though the oil went into the water, it quickly came to the top.
Pour a bit of salt into the jar. What happens when you add the salt? Why do you think this happens?
Continue adding more salt. As you add the salt and the grains of salt get trapped in the oil, the salt falls to the bottom of the jar. As the salt falls to the bottom, it takes the oil around it to the bottom of the jar as well. Once the salt gets to the bottom of the jar, it settles there. The oil that is no longer weighed down by salt separates and rises back to the top of the jar. Continually adding a little salt at a time will make the inside of the jar look like a lava lamp.
Sources: Find these ideas and more science-themed projects at clubscikidzmd.com.
Thanks to Michelle Aguirre and Ceoli Jacoby, who also contributed to this article. A portion of this article originally appeared in Washington FAMILY, a sister publication of Baltimore’s Child.