Trying to introduce younger children to science (or even slightly older ones, for that matter)? Nothing impresses more than an easy, exciting and rewarding experiment. You don't need test-tubes and Bunsen burners to open minds, just a little scientific knowledge and imagination...
5. Cola and Mentos
A home experiment classic, which comes in a variety of forms. The basic principle is the application of Mentos sweets to a cola product (hearsay evidence suggests Diet Coke works the best), which results in an eruption! Why does this happen? The pores on the surface of the sweets catalyse the release of Carbon Dioxide in the cola, causing an eruption. You can either put the sweets in and enjoy the show, or experiment with adding variables to the mix, or different actions (adding the sweets and then quickly closing the lid - when thrown to the ground, the pressure is released and the bottle shoots up like a rocket!). Be advised: do this experiment outside.
4. Avocado Tree
Less dramatic than the previous experiment, but much more rewarding. The basic principle here is to suspend an avocado stone half in water, with the top half exposed to the air. This can be accomplished however you like, but an easy way is to stick toothpicks into the stone around is circumference and place it over a tall glass of water. Leave it on the window sill and make sure the water is regularly topped up - don't let the level drop! Eventually a shoot will appear from the top of the stone - once it grows to about six inches (and leaves develop), you can plant it in the garden (make sure it's in a warm, sunny place) and watch your avocado tree grow!
3. Liquid Rainbow
This experiment is easy, pretty, and informative. The general idea behind it - one that you can explain to kids fairly easily - is that liquids of different densities will seemingly 'float' on top of each other, instead of mixing. To get good results you need a fairly stout transparent container, to minimize the 'fall distance' when you're pouring the various liquids (so they don't mix too much!). Start with a base of honey, treacle, golden syrup or corn syrup (whichever you have). Then carefully pour in some washing up liquid. Then water (feel free to add food coloring to make it more exciting, or use juice or milk). Then Vegetable Oil. And finally, a clear spirit. Don't worry if they all seem to mix at first, leave it for a while and it will all separate out, creating a weird liquid rainbow.
2. Grow your own edible Sugar Crystals
We're getting into mind-blowing territory (growing crystals?). For this experiment, all you really need is hot sugar water, string, and a little patience. The theory? The sugar in the water will latch on to the string as the water evaporates (usually over the course of a week or so), leaving a mass of sugar crystal with a string down the middle. To achieve this, you need to saturate water with sugar (by boiling it on the stove and adding sugar and letting it dissolve, until no more can be dissolved), and pour it into a tall, thin glass or jar. Then (using a pen, pencil, large match stick or similar), suspend a piece of string in the solution, perhaps with a weight on the end (a paperclip will do) to make sure it keeps vaguely straight. Wait for the week, then eat the results!
1. Potato Battery
If there's one experiment that is guaranteed to make a kid speechless with amazement, it's this one. The whole idea that a potato can power electrical items is so contrary to logic and everyday experience that they're guaranteed to be amazed. For this experiment you'll need two potatoes, two galvanized nails and two copper nails (or copper wire), 3 mini 'jump-leads' with crocodile clips (you can get them incredibly cheaply online), and a battery-powered electrical device (an alarm clock works well). Stick one galvanized nail and one copper nail (or copper strand) in each potato, as far apart as possible. Remove the battery from the device. Connect the device's positive terminal to the copper of one potato, and the negative terminal to the galvanized nail of the other potato. Then link up the potatoes with the remaining wire. Result? Potato power.