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. 

For this saltwater density experiment, you’ll fill four clear glasses with water, then add salt to one glass, sugar to one glass, and baking soda to one glass, leaving one glass with just water. Then, float small plastic pieces or grapes in each of the glasses and observe whether they float or not. Saltwater is denser than freshwater, which means some objects may float in saltwater that would sink in freshwater. You can use this experiment to teach kids about the ocean and other bodies of saltwater, such as the Dead Sea, which is so salty people can easily float on top of it.
Ever got an electric shock off something? Demonstrate the science behind the shocks with this jumping frogs experiment. With just a balloon, some sugar paper and a woolly jumper, you’ll have frogs leaping in no time demonstrating the power of static electricity. It doesn’t have to be frogs either, let your imagination run wild to create some other jumping stars of this easy science experiment!
By building a lung model, you can teach kids about respiration and how their lungs work. After cutting off the bottom of a plastic bottle, you’ll stretch a balloon around the opened end and insert another balloon through the mouth of the bottle. You’ll then push a straw through the neck of the bottle and secure it with a rubber band and play dough. By blowing into the straw, the balloons will inflate then deflate, similar to how our lungs work.
Kids ages 5-8 are at a crucial time in their understanding of science, math, and engineering. They're old enough to grasp how big ideas like the solar system and flight, things that perhaps once seemed magical, have scientific properties that allow us to explore outer space and build rocket ships. Kiwi Crate allows children in 1st, 2nd, and 3rd grade to begin a hands-on discovery of physics, chemistry, biology, and more, with fun projects that they can assemble themselves.

It takes a few hours to see the results of this leaf experiment, but it couldn’t be easier to set up, and kids will love to see a leaf actually “breathing.” Just get a large-ish leaf, place it in a bowl (glass works best so you can see everything) filled with water, place a small rock on the leaf to weigh it down, and leave it somewhere sunny. Come back in a few hours and you’ll see little bubbles in the water created when the leaf releases the oxygen it created during photosynthesis.
Ever got an electric shock off something? Demonstrate the science behind the shocks with this jumping frogs experiment. With just a balloon, some sugar paper and a woolly jumper, you’ll have frogs leaping in no time demonstrating the power of static electricity. It doesn’t have to be frogs either, let your imagination run wild to create some other jumping stars of this easy science experiment!
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.
You’ve probably tried a salt crystal growing kit at some point in your life (5th grade Science Fair perhaps?) but Schooling a Monkey takes the idea to a new level with these Salt Crystal Feathers. This awe-inspiring project is deceptively simple and inexpensive to achieve, and requires just a wee bit of patience to see the results—kids will love checking in on the progress. Visit Schooling a Monkey now to get started.

Can you and the kiddos solve the mysterious case of the disappearing egg shell? Following the simple how-to at Go Science Girls, you’ll learn the step-by-step and talking points about the process along the way. Warning! Although it’s totally non-toxic, toddler aged kids will be tempted to squeeze the egg at the end so make sure it’s a supervised experiment. Visit Go Science Girls to get cracking!
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.
Learn interesting science and technology facts by experimenting with different materials that react in surprising ways. You'll find a lot of experiments can be done using simple ingredients found around your house (with adult supervision of course). Basic materials can help you perform experiments that are simple, safe and perfect for kids. Enjoy our fun science experiments, make cool projects with easy ideas for children, show friends & family what you've discovered and most importantly, have fun!
Call the emergency services straight away if anything goes wrong. However these are all well-tested and very safe for the ages provided by the manufacturers, so rest assured this is only a formality, but it is good to be safe and start young with proper preventative measures. After all, what you start now will set the example for what they grow up to be.
Be careful: The water only has the power to make the sugar crystals “invisible” when it’s piping hot. After the water cools down and evaporates, the sugar turns back into a solid. And with a little help of your sugar-soaked string, the crystals will find a home to grow upon and become rock candy. Learn how to make your smart sweets with these instructions from the Exploratorium. 
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