These sound like big words for our little ones, but there’s an easier way to break it down. Water and oil won’t mix because they’re not the same “weight” or substance (just like clay and LEGOs won’t become one). Now add a drop of food coloring (which is heavier than oil) and a fizzy tablet and watch the air bubbles take coloring with them to the top. Head on over to S. L. Smith’s blog to see how it’s done.
This grow-your-own experiment that lets you grow crystals inside an egg shell. Be sure to get alum powder that contains potassium, or else you won't get any crystal growth. Adding drops of food dye to the growing solution yields some super cool crystals. A perfectly formed geode takes about 12-15 hours to grow, making this a great weekend project. Check out more of Art and Soul's gorgeous eggs over at their blog!

This is the most kid friendly and fun lab kit you can get. My kids are ages 2 and 4 and cannot get enough of this. Everything in the kit is high-quality, and this kit lasts a very long time. We have done these experiments over and over for 3 months and only recently have used an entire bag of something. I admit to even being impressed by how cool the activities are. This is worth every single penny. I will 100% be ordering another kit when we deplete all the things in ours.

With just some basic materials you can create your own musical instrument to teach kids about sound waves. In this water xylophone experiment, you’ll fill glass jars with varying levels of water. Once they’re all lined up, kids can hit the sides with wooden sticks and see how the itch differs depending on how much water is in the jar (more water=lower pitch, less water=higher pitch). This is because sound waves travel differently depending on how full the jars are with water.
With just a package of Starbursts and a few other materials, you can create models of each of the three rock types: igneous, sedimentary, and metamorphic. Sedimentary “rocks” will be created by pressing thin layers of Starbursts together, metamorphic by heating and pressing Starbursts, and igneous by applying high levels of heat to the Starbursts. Kids will learn how different types of rocks are forms and how the three rock types look different from each other.
When these nails and copper wires collide, heat is generated (psst ... heat is a result of expended energy, so you can explain to your little runner why he feels warmer after a race around the house). But with some potato magic, the properties of the nail and copper stay separated, allowing the heat to become the electric energy needed to power up your devices. Build your own potato battery with this tutorial from PBS Kids.
This blood model experiment is a great way to get kids to visual what their blood looks like and how complicated it really is. Each ingredient represents a different component of blood (plasma, platelets, red blood cells, etc.), so you just add a certain amount of each to the jar, swirl it around a bit, and you have a model of what your blood looks like.
Making an electromagnet at home is fun and easy. Most magnets, like the ones on many refrigerators, cannot be turned off; they are called permanent magnets. This one can be and is therefor called an electromagnet. They run on electricity and are only magnetic when the electricity is flowing. The electricity flowing through the wire arranges the molecules in the nail so that they are attracted to certain metals.
This celery science experiment is another classic science experiment that parents and teachers like because it’s easy to do and gives kids a great visual understanding of how transpiration works and how plants get water and nutrients. Just place celery stalks in cups of colored water, wait at least a day, and you’ll see the celery leaves take on the color of the water. This happens because celery stalks (like other plants) contain small capillaries that they use to transport water and nutrients throughout the plant.

With a combination of a solid fuel source and a liquid oxidizer, hybrid rocket engines can propel themselves. And on a small scale, you can create your own hybrid rocket engine, using pasta, mouthwash and yeast. Sadly, it won’t propel much, but who said rocket science ain’t easy? Check out this video from NightHawkInLight on how to make this mini engine. 

Scientific Explorer's Mind Blowing Science Kit includes almost everything you need to set up exciting, colorful experiments with your young scientist. Included in this dynamic kit are the following components: red cabbage juice powder, citric acid, color tablets, polyacrylamide crystals, a pipette, small and medium scoops, and three plastic cups. Only basic supplies are required but not included, such as water, towels, a plate or tray to catch spills, and a stirring spoon. Although none of the experiments included in this kit are especially messy, each one should be done on a flat surface that can be easily wiped clean in case of spills.
Have you ever gone into a cave and seen huge stalactites hanging from the top of the cave? Stalactites are formed by dripping water. The water is filled with particles which slowly accumulate and harden over the years, forming stalactites. You can recreate that process with this stalactite experiment. By mixing a baking soda solution, dipping a piece of wool yarn in the jar and running it to another jar, you’ll be able to observe baking soda particles forming and hardening along the yarn, similar to how stalactites grow.
There are many fun ways to get your children into natural science and Geodes are one way. This starter kit has 7 unique and fascinating ways to get discovered the mystery of the earth crust. Geodes are natural and a wonder to many who like to collect, but even as a one-off this is a great way to get kids thinking. This is fun and the breaking aspect always makes things interesting for those that need some initial enthusiasm.

Invisible inks either react with another chemical to become visible or else weaken the structure of the paper so the message appears if you hold it over a heat source. But we're not talking about fire here. The heat of a normal light bulb is all that's required to darken the lettering. This baking soda recipe is nice because if you don't want to use a light bulb to reveal the message, you can just swab the paper with grape juice instead.

Geode Kits – For any child who thinks rocks are boring – a kit where they can break open their own geode is a great way to change their mind. National Geographic is a great choice if this is the type of kit you are looking for. Their products include hand-picked geodes and come with safety goggles and a stand for your child to proudly display their treasures. A great choice for children aged around 6 years old and above, they’re sure to be more interested in Earth science after this experiment.