Lava lamps that you see in stores are pretty amazing: they have blobs of colored stuff that float slowly up and down in a cylinder of liquid that’s lit from beneath. While the lava lamps you buy for your home use complex chemical reactions that involve high temperatures and electricity, you can make one at home using simple ingredients you find in your kitchen! How cool is that?
Fill your bottle with vegetable oil, to about one inch from the top. Then add about a tablespoon of water. Add a few drops of food coloring to the water (the water will be sitting on top of the oil – why do you think that happens?). Use a dark color like blue or red, or a color that will contrast with the color of the oil. Yellow food coloring doesn’t work as well, particularly with oils like corn oil. Then, break a single Alka Seltzer tablet into pieces and drop all the pieces into the bottle. Put the cap on the bottle and seal it tightly. Place the flashlight behind the bottle so it shines through the liquid and watch the reaction in the bottle. It looks a lot like a lava lamp, doesn’t it?
When the reaction starts to slow down, feel free to break up more Alka Seltzer tablets and add them to the bottle to restart the reaction. What exactly is happening in the bottle? Why does the movement start when you put in a fresh Alka Seltzer tablet and slow down after a while? Why is the color moving through the oil in "blobs”?
You’ve probably seen movies or TV shows where spies use sneaky ways to get messages to each other. Well, you can sneak important messages to your friends or family by using invisible inks that magically appear when treated with a "secret ingredient”! All you need are a few simple household ingredients and some chemistry knowledge, and you’re on your way to being mysterious, intriguing and smart, as well as having an amazing science fair project or science experiment!
What you’ll need:
- Baking soda
- Purple grape juice concentrate
- A cotton swab, toothpick or paintbrush for writing with your invisible ink
- A piece of regular white paper
Mix the baking soda with equal parts water. Depending on the length of your message, a tablespoon of each will usually do the trick. Dip your "pen” (cotton swab, toothpick or paintbrush) into the mixture and write your secret message out on the paper. Be sure that your "pen” stays moist and full of ink as you write, so the whole message appears when you add the secret "decoder” ingredient later. Once you have finished your message, let the paper dry completely.
Once dry, you can read the message one of two ways. The first is to use purple grape juice concentrate. The concentrate will cause an acid-base reaction with your ink. Get a brush and dip it into the juice and then brush it across your paper. Be sure to coat it well, and be sure not to get any grape juice on your clothes or on counters that can stain. After a few minutes, what happens? Can you read your message? How does the acid-base reaction cause the ink to be readable?
The second way to read your message is to take your message (a different one that has not been decoded yet with grape juice) and hold it up to a tungsten light bulb that has been on for a bit. Be sure to use a regular light bulb and not a halogen bulb (halogen bulbs are too hot).
Also be sure that the paper isn’t touching the bulb and that the paper itself doesn’t start to burn, smoke or turn brown. Make sure to have an adult with you if you choose to decode your message with this method. The light bulb will heat the paper and the ink. What happens? Are you able to see the hidden message? Why do you think the "ink” suddenly becomes visible with the addition of heat?
3. Grow a Big Crystal
Crystals are really cool, and growing them is a great chemistry science fair project or chemistry science experiment. The easiest crystals to grow are alum crystals. They are non-toxic and can be grown by stuff you find in your kitchen.
What you’ll need:
- 2 clean jars (1 quart mason jars – the kind that you make jellies or candles in – work the best
- ½ cup of hot tap water
- 2 ½ Tablespoons of alum (you can buy it in the spice section of grocery stores if your parents don’t have any handy)
- Nylon fishing line
- A Popsicle stick, pencil, ruler or butter knife
- A spoon
- A paper coffee filter or paper towel
Pour ½ cup of hot tap water into one of your two jars. Make sure the jars are clean and dry. Slowly stir in the alum. Alum is non-toxic. It’s used to make pickles and keeps them crispy. Don’t add all the Alum at once. You’ll want to slowly add it and keep stirring the solution until it the little bit you’ve added has dissolved into the water. Then add a little more and stir it again until it disappears. Keep doing this until the alum stops dissolving in the solution. You probably won’t need the whole 2 ½ tablespoons, but it all depends on the size of your jar. If you do use all of it and it’s still dissolving in your solution, then get more and keep adding it until it stops.
Once you’ve saturated your solution with alum, cover the jar with the coffee filter or a paper towel to keep dust out, and leave the jar sit overnight. The next day, you’ll see some small crystals at the bottom of the jar. Pour the liquid into your other clean jar so you can get at the crystals that formed on the bottom. Pick the largest and best formed of these crystals and throw away the rest. This is going to be your "seed” crystal from which you’ll grow a single, big crystal.
Tie the nylon fishing wire firmly around the crystal and then tie the other end to a flat object (popsicle stick, pencil, ruler or butter knife). You’re going to be hanging your crystal in the jar from this flat object, so you want to be sure that line is the correct length: you’ll want the crystal to be suspended in the middle of the jar but not too close to the bottom. You may need to adjust the length of the fishing wire until the crystal is positioned correctly in the jar.
Once the line is at the right length, hang the crystal in the jar with the alum solution and cover it with your coffee filter or paper towel. Leave it soaking in the solution and watch it grow! It can take up to a few weeks for the crystal to grow to a significant size. The longer you leave it grow, the larger it will get.
If crystals start growing on the side or bottom of your jar, pour the solution back into the first jar (which you’ve cleaned since you used it the first time) and hang your crystal in this jar with the liquid. Other crystals will compete with your crystal, so you don’t want them growing in the same jar or yours will not grow as large as it could.
Why do you think crystals start to grow in the solution? Why does your crystal keep growing larger over time? How does the shape of your crystal tell you about the chemicals that are in the solution?
Additional Ideas from Be Amazing! Toys
The scientists at Be Amazing! Toys avidly support the International Year of Chemistry, and they have put together a list of science kits and toys that are great chemistry science fair projects and chemistry science experiments. These science projects and science experiments are very cool and use common materials from around the house. They are easy to perform and use everyday ingredients like Mentos, Diet Coke, and magnets, yet they result is some of the neatest stuff your friends and family have seen. Here are some of their most popular kits:
1. The Amazing Diet Coke and Mentos Geyser TubeTM Experiment
Not only are Mentos® great to eat, but these amazing candies are loaded with wonder and curiosity. The Amazing Diet Coke and Mentos Geyser Tube Experiment teaches you how to create an enormous geyser by combining Mentos® with soda. The eruption is incredible – up to 25’ high – and so is the learning if you consider the science just beneath the surface. The Geyser Tube™ allows you to load the candies and safely dispense them into the soda bottle.
2. Cool Slime
Have you been searching for the perfect slime? Look no further! The Cool Slime Kit contains two liquids that when mixed together, make the perfect batch of green, gooey slime every time (maniacal mad scientist laughter is optional.) Along the way, you’ll learn about molecules, polymers, and the safe and amazing chemical reaction that turns two innocent-looking liquids into a blob of oozy, green goo.
Once you are done making slime, the enclosed directions walk you through some amazing slime games. The slime is lots of fun to play with, and can be stored in a zipper-lock bag until you are ready to play with it again. The liquid slime components store in their bottles for even longer, so you can whip up a batch of slime whenever your inner mad-scientist demands it.
3. Blizzard in a Bucket
Blizzard in a Bucket is a cool new twist on the old sand bucket. Just add water to a scoop of Insta-Snow® powder to create an eruption of snow – instantly! Watch Insta-Snow® grow as it expands 100 times its original size. But that’s not all – there are many more fun science experiments inside.
Using this kit you can instantly grow snow and make loads of it, just by adding water. You can make a Scientific Sno-ball that looks and feels like the real thing, even in the summer! You can learn everything you’ve ever wanted to know about snow, like why is it white? Are all snowflakes really different? Blizzard in a Bucket is full of lots of great exploration ideas.
4. Superabsorbent CrystalsTM
Get ready for some squishy, jelly, science fun! The Superabsorbent CrystalsTM kit contains an amazing substance called the superabsorbent polymer, which means that by adding water, you can turn these tiny crystals into big, squishy crystals made of goo!
These incredible crystals are members of an amazing scientific family called the superabsorbents, and they drink up 150-300 times their weight in water. When removed from water, they shrink back down to their original size, and can be used again and again. You can learn to make them disappear and reappear like magic (except that it’s better than magic – it’s SCIENCE!) The instructions are packed with intriguing activities that make great hands-on activities or science fair projects.
With your adult assistant’s help, the possibilities for discovery are only limited by your imagination. Set up a laboratory with a water-safe surface and get ready to explore! Find out the answers to questions like: Do crystals grow in anything besides water? What happens if food coloring is added to the water before you drop your crystals in the water? What will happen to the jelly crystals if you put them in the freezer? Can you use jelly crystals to sprout seeds?
What else can you think of?
- BeAmazing Toys: http://www.beamazing.com.
- Lava Lamp – Make a Lava Lamp, by Anne Marie Helmenstine: http://chemistry.about.com/od/homeexperiments/a/makealavalamp.htm .
- How to Make Invisible Ink – Baking Soda, by Anne Marie Helmenstine, Ph.D: http://chemistry.about.com/cs/howtos/ht/invisibleink2.htm.
- How to Grow a Big Alum Crystal, by Anne Marie Helmenstine, Ph.D: http://chemistry.about.com/cs/howtos/ht/alumcrystal.htm.