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.
The kit includes components that can be used to breed bacteria and experiment with genetic engineering. If you know a child who’re itching to investigate the field of genetics, then this product might serve as a great gift. The Thames & Kosmos Biology Genetics and DNA kit takes children on a journey through reproduction biology, chromosomes and cell components. 

Below are 37 of the best science projects for kids to try. For each one we include a description of the experiment, which area(s) of science it teaches kids about, how difficult it is (easy/medium/hard), how messy it is (low/medium/high), and the materials you need to do the project. Note that experiments labelled “hard” are definitely still doable; they just require more materials or time than most of these other science experiments for kids.

Can you make water float? We bet you can. No, you don’t need to be a wizard or a witch. You don’t need to cast a spell. There’s nothing magic about it at all, in fact. You can make water float using good, ol’ fashioned, awesome science. The “trick” to this experiment is air pressure. Get everything you need and the how-to, right here, thanks to Mike Adamick and his book, Dad's Book of Awesome Science Experiments.
Chemistry Kits – Perhaps the most classic of the science kit options, these are great for kids who are interested in learning about how things work. There is a huge range of kits in this bracket, ranging in features and suitability. There is a chemistry kit for just about any child, and with a bit of research it’s easy to find one to suit your child’s age and ability.

Kids this age will probably enjoy a whole range of different science kits. It’s good to look for something which will help with what they are learning about at school. Pre-teens are becoming more and more independent, so it might be worth looking for an experiment kit which is simple enough for them to do alone, but still hard enough to keep them entertained and learning.
Ah, slime. It’s the one thing that parents across the UK have been being pestered to make, so why not turn it into a science activity? For our concoction, we mixed shaving foam, PVA glue and a little bit of air freshener (fabric conditioner can work too!), to create a slime that you can swirl, stretch and crack, providing hours of fun. Try changing the quantities to see how the mixture changes, and ask the kids to explain the differences.
Insert a little plant science into the mix by re-growing food from scraps. Think onions, potatoes, and lettuces for this one (psst… green onions are a super easy, fast option). Get the low down on all that recycled goodness at Mrs. Happy Homemaker. Since plants need water and sunlight to grow, exposing scrap roots to that winning combo helps them recharge.
Scientific Explorer's Mind Blowing Science Kit makes it possible to create your very own science lab at home. This smartly designed science kit allows young scientists to perform several amazing science experiments that range from erupting a color-changing volcano to growing colorful, jiggly crystals. Young scientists will learn about basic principles behind the science including the difference between acids and bases, and how to use a test tube and pipette. Although designed for use by children ages four and older, adult supervision is needed for safety and to ensure that young scientists get the most out of the Mind Blowing Science Kit.
This Rainbow Skittles science experiment can be done in seconds, making it a great way to try science at home even with the most easily distracted of toddler-sized assistant. All you’ll need to do is arrange Skittles in a circle on a plate and fill the middle with warm water. Then sit back and watch as the colours drain and mix with the water, creating a cool rainbow pattern in front of your eyes. Plus, any bonus Skittles = a tasty treat for you.
Younger children are most likely to be interested in something which is very hands-on, and gives results quickly. They probably won’t be interested in growing a crystal, and are probably a bit young for something like a robot building kit. Young kids will be most likely to enjoy a gross science kit, or a volcano kit. Also think about safety features when buying for younger children. Make sure they won’t eat anything they shouldn’t, or there are no small parts which could be dangerous.