'Tis the Season... For Science Fair Projects

Alum crystal, courtesy of Wikipedia Commons.

This year my son's classroom is growing alum crystals for their group science fair project. Already it has yielded exciting results!  If you need a project that is fairly easy for elementary students to conduct, this is a good one.

Even after the first day of creating the seed crystals, we have great variation in seed-crystal sizes among students.  The students record the pH of their solution every day in their science journals, and we also have a measure of what I like to call the "cloudiness factor" of their solution, which is basically a simple way of describing how cloudy each student's water was when they were dissolving their alum in solution. Over the next couple weeks, the students will begin to hypothesize about the relationship between crystal growth and the basic chemical and physical properties of their initial crystal-growing solution.

If you want to try growing alum crystals at home, here is what you'll need.

Materials

1 jar of crystalline alum (found in spice aisle of grocery store)
2 jelly jars (big enough to hold at least 1 cup of water, each, and to withstand high temperatures)
1 - 2 cups RO (reverse osmosis) or distilled water
stainless steel stirring spoon
dental floss
pencil

Methods

Day 1:

Heat water to near boiling.
Pour 1 cup of water into one of the jelly jars.
Slowly pour some of the alum (approx. 1 - 1/2 tablespoons) into the water.
Stir until all the alum dissolves in the water.
Add more alum slowly, continuing to stir, until it no longer dissolves in the water (it will be approximately 2 and 1/2 tablespoons, more or less, when you're done).
Set aside in quiet place where it won't be disturbed, and cover with paper towel overnight.

Day 2:

You should have several seed crystals growing along the bottom of your jar.
Use a spoon to pick your favorite one. Set aside.
Decant the solution into the 2nd jar, leaving the remaining crystals behind. You can discard these or set them aside for another project.
Tie a long string of dental floss around the crystal. It should be long enough to wrap plenty of extra string around the pencil on the other end of the string.
Hang the pencil over the top of the 2nd jar, with the string and crystal hanging down into the solution.
Roll up the pencil and string until the crystal is hanging just beneath the water line.
Clean the 1st jar and leave to dry for the next day.

Day 3 and beyond:

Repeat the process of pouring the solution into the other jar and rehanging the crystal until it stops growing! Sometimes this can take up to 2 weeks, depending on how concentrated your solution was to begin with.

You will be amazed at the results!

Science Experiments You Can Do at Home

Here are some fun Weird Science experiments you can reproduce at home! Most of these are adapted from Steve Spangler Science©. Because Steve is a Science Education Correspondent for Denver’s Channel 9 News, you can watch some of his fun videos on their website (http://www.9news.com/news/education/spangler/default.aspx)

Can you skewer a balloon without popping it?

Materials needed:

1 or more balloons

1 barbeque skewer

a little vegetable oil (any kind will work)

What to do:

1. Blow up a balloon and tie the end.
2. Dip the sharp end of the barbeque skewer in vegetable oil.
3. Look for the “darker spots” of the balloon, or places where the latex molecules are more dense (hint: the top and bottom of the balloon is a good place to start looking).
4. Slowly and tenderly pierce the skewer through a dark spot of the balloon. Then guide it all the way through the middle of the balloon until you reach another dark spot on the other side. Gingerly pierce the other side and…

Voila! You’ve skewered a balloon! 

The science behind it:

The latex molecules that make up the balloon are the least stressed near the top and bottom of the balloon, whereas they are the most stressed (stretched out) along the sides of the balloon. At the ends of the balloons where the molecules aren’t as stretched out, these long molecular chains wrap themselves around the place where you inserted the skewer, consequently keeping the air from escaping the balloon.

Fireworks on a plate!

Materials needed:

3 plates

1 cup of whole milk

1 cup of 1% milk

1 cup of water

food coloring (several colors are best)

Dawn soap

1 or 2 Q-tips

What to do:

1. Cover the first plate with whole milk.
2. Cover the second plate with 1% milk.
3. Cover the third plate with water.
4. Put several drops of food coloring (different colors) in each liquid, in the center of each plate. Be careful not to stir them.
5. Dip one end of a Q-tip in Dawn soap, then dip the same end in the center of the plate with the water and food coloring. What happens? Watch it for a minute or so.
6. Dip a Q-tip in the soap again. Then dip it in the center of the plate with the 1% milk. What happens this time? Again, watch for a minute. Does the food coloring move around more than it did in the water?
7. Finally, dip the Q-tip in soap one more time. Now dip it in the center of the plate with the whole milk. Watch the food coloring for a while. How long does it move around the plate compared to the water and 1% milk?

The science behind it:

Soap is a bipolar molecule. This means that one end of the molecule is polar, and one end is non-polar. The polar end is attracted to water, while the non-polar end is attracted to the fat in the milk. The soap therefore weakens the bonds that keep the fats and proteins in the milk solution. The food coloring is just a “tracer” that allows you to watch it happening!

Upside-down water!

Materials needed:

1 ball jar, with ring that goes around the lid

1 piece of screen (window screen, shade cloth, or similar; large enough to cover top of jar)

1 piece of card stock or similar paper

Water

What to do:

1. Take the lid off the ball jar and place the screen over the top.
2. Screw the ring on the jar to hold the screen in place.
3. Fill the jar to half or ¾ full with water.
4. Place a piece of card stock over the top, so that it completely covers the screen.
5. Holding the cardstock securely in place, turn the jar upside down (over the sink or outside is best!).
6. Ask your child to hypothesize what will happen when you remove the cardstock.
7. Slowly remove the cardstock by sliding it off to the side and then away from the jar.
8. Keep the jar stead and perfectly vertical for this to work!

The science behind it:

The water stays in the jar because of surface tension. Water molecules stick together because of a force called cohesion. This force causes the water molecules to essentially “glue” themselves together between openings in the screen, and this surface-tension “membrane” that is formed is what holds the water in the jar. It is also the reason why raindrops are spherical.

Shuttle Endeavour makes a final voyage through Los Angeles!

Starting at near midnight on Thursday, October 11th and continuing through Sunday morning, October 14th, 2012, the Space Shuttle Endeavour completed it's final "mission:" A 12-mile trek through Los Angeles from LAX airport to the CA Science Center. Weird Science was there to see it!  Here is a link to a YouTube video with still frames and some movie footage from the first night (and a cold one, at that, as you can see by the heavy blankets we wrapped around ourselves), as well as the 2nd day of the trip. We stayed up to watch the whole thing. It was an exciting and historic moment!

Click Here for YouTube video of Space Shuttle Endeavour in LA.

Bernoulli's Dancing Balloons

This is one of my favorite experiments for all ages. The kids at Khalsa-Camden did this last Fall and had a ball (literally). It is a wonderful experiment to show the relationship (that the famous scientist Bernoulli explained between) between velocity and pressure, using balloons, fans, and beach balls. This experiment is best done outside on a still day with no wind. Here's what you need to get started:

• a floor fan that can pivot vertically to horizontally, so that it can be positioned to blow upward (while leaving some airspace under the fan).
• balloons (already blown up).
• beach balls of all sizes.

Have your kids hypothesize about what they think will happen to the balloons if you turn the fan on (blowing upward) and let go of the balloons over the blowing air. Do the same with the beach balls.

What you should find is that once you let go of the balloons or beach balls, they will travel upwards in the air stream. Most kids will expect the balloons or balls to fly everywhere and for the them to fall back down to the ground. However, once the balloons and balls travel high enough in the air stream, they will appear to "dance" in the air and not fall down or fly outward away from the air stream. The reason they stay where they are is because the faster air blowing upward from the fan is creating an area of lower pressure than the surrounding air. The balloons and balls are "trapped" in the low-pressure area and will only come down when the fan is turned off or if a gusty wind pushing them along.

The kids will have the most fun when you place several balloons over the fan rather than just one. Try it at home and let me know if it worked for you!

Venus Transit Tuesday, June 5th

Don't forget to head down to Flandrau Science Center at the UA campus this Tuesday night for the Venus transit! This means that Venus will be passing in front of the Sun. Much like a solar eclipse, where the moon comes between Earth and the Sun, Venus will be passing across the face of the Sun in the same manner. The difference is that Venus will appear much smaller than the moon because of its distance from the Earth. Admission is free and they'll have solar telescopes available for viewing, as well as science demonstrations and other fun activities. Check out the Flandrau website for more info!

http://www.flandrau.org/

Here is a video NASA produced on YouTube about the Venus transit:

Solar Eclipse

We took some photographs of the solar eclipse that happened on Sunday at sunset here in Tucson. If you weren't lucky enough to catch it, or if you live somewhere where it couldn't be seen, here are a couple neat photographs. We took these through a small solar-filter scope. Our neighbors provided the best view through their 10" telescope with a solar filter on it! The first photo was taken shortly after the eclipse started. The second photo is close to the full eclipse, which occurred around 6:40 pm MST.

Bubble Geometry

Steve Spangler is one of my favorite "fun" scientists. He does a segment on fun science experiments for the Denver 9 news. I wanted to share one of his experiments that I'm going to do with my preschool group next week. But first a preface...

I am used to using bubbles as a perfect segue to teaching kids of any age about surface tension and atmospheric pressure. No matter how hard they try and no matter what kinds of wands they use, the resulting bubble is always a perfect sphere! But in this experiment, Steve Spangler shows us how to make cubed bubbles. I never thought it possible until I watched his video. This is something you can do at home, and I plan to make my apparatus out of straws and balls of clay. I think Tinker Toys would also work great for this, if you have them. I'll give you an update on what materials I use after I experiment with it a bit. Meanwhile, check out this cool video from Steve Spangler's page!

"Cracking the Egg Sprinkler Mystery" on NPR's Science Friday!

While I was listening to Science Friday on the radio today, I was most intrigued by a small excerpt they included at the end about an experiment that sounded like fun! Apparently, this experiment was fueled by a scientist at BYU, who got the idea from a former professor, who got the idea from an old high school teacher, and so on and so on. You get the picture. Who knows how far all these fun experiments go back in time? No matter. The point is, they're still fun and they're timeless.

The gist of the experiment is simple, and anyone can do it, even your preschooler. You pour milk out into a puddle on your kitchen counter. Spin a hardboiled egg in the milk and watch the science unfold. The milk will literally crawl up the side of the egg and then spray out from the egg's "equator," like a miniature sprinkler system! And the mystery behind the science? Well, it's really no mystery at all if you're familiar with a man named Bernoulli. Bernoulli developed my favorite equation in the whole, wide world, which relates velocity with pressure. The higher the velocity of air or liquid, the lower the pressure. Incidentally, hydrology-minded people like myself use this equation indirectly every day, because Darcy's Law-- an equation that describes the movement of groundwater-- was derived from Bernoulli's Principle.

You can see Bernoulli's Principle in action using a hardboiled egg and various other objects on the Science Friday video at:

http://www.sciencefriday.com/video/05/04/2012/cracking-the-egg-sprinkler-mystery.html

Welcome to Weird Science!

Everywhere I go, I see science at work. Whether I'm flying in an airplane, driving through the desert across the Colorado River canals, or popping popcorn over the stove, I'm thinking about how science is part of our everyday lives. I am continuously pondering how to use these often-overlooked but incredible engineering miracles and natural processes as a base for enriching and fun science activities for kids. When I started to write down all these ideas and began testing them out on the kids at my oldest son's school, the Weird Science program was born!

Weird Science is an exploratory and inquiry-based extracurricular science program. We specialize in pre-K through 4th-grade students. Young minds are naturally inquisitive about the world around them and thirsty for knowledge. As a result, these students make fantastic scientists, and the inquiry approach is cultivated easily at this age. Our program provides 5 - 9 year olds with the knowledge and skills to be competent explorers of science, technology, engineering, and math (STEM) concepts and to envision themselves as future STEM professionals.

Weird Science offers a variety of STEM investigations of favorite childhood pastimes, such as paper airplanes, balloons, magnets, and making bubbles, as well as new topics such as biofuels and more. We expect the participation by young learners to generate enthusiasm and motivation for science and science careers. Above all, this program changes attitudes about the requirements for becoming a scientist and perceptions about who can be a scientist.

Participants will develop 1) increased interest in and appreciation for STEM, 2) new and demonstrable skills in thinking and experimenting in a scientifically valid way, applying engineering, math or technology principals to solve problems, and communicating results, 3) increased self-confidence in STEM abilities aligned with the child's ability to do inquiry and problem solving, and 4) awareness of the path to become a scientist or engineer and the roles they play in society.