Lisa Salmon catches up with stay-at-home dad Sergei Urban, to discover how to wow kids - and keep boredom at bay.
The summer holidays can seem like a lifetime as parents struggle to keep younger children entertained.
But stay-at-home dad Sergei Urban doesn't have that problem. Despite having no background in science, arts and crafts or even as a teacher, the former economist enjoys creative play, experiments, easy-to-make crafts and educational toys so much with his sons Max, aged four, and Alex, six, that he's made a career of sharing them with other parents through TheDadLab.
With more than three million fans across TheDadLab's social media channels, Urban has quickly become an online sensation because of the way he uses everyday household items like ketchup, string, balloons and paperclips to wow kids with the amazing forces of natural science - from pouring water sideways to standing on eggs without them breaking.
He says: "I'm not a scientist or a teacher, I am a full-time dad. I created TheDadLab to share creative projects that we do at home with as many parents as possible, to inspire them to spend more quality time with their kids and to develop a thirst for knowledge and understanding in those curious little minds."
And now the playful dad has widened his audience by detailing his easy experiments in TheDadLab book (Blink Publishing, £14.99), which aims to help parents introduce simple science to their children at an early age.
The new book features 40 projects, with a simple description, and information for parents to help explain to their child how and why the project works.
"The experiments offer some great inspiration for parents to make the most of their time with kids, encouraging them to get creative with hands-on projects," says Urban. He says none of the activities require any special equipment or skills, and points out: "Sometimes, by doing a simple craft, a child can learn about science, technology, engineering and maths without even realising it. At the same time, parents can enjoy quality time with children and create memories for life."
Here are four of TheDadLab projects to try:
1. Fossil dinosaur eggs
All you need is a freezer, balloons, a toy dinosaur and a hammer.
Gently pull a balloon over a dinosaur, making sure not to let horns and spikes puncture it. Choose smaller figures that fit in the balloon easiest. Blow up the balloon with the dinosaur inside and deflate it to give the rubber some more flexibility. Then pull the neck of the balloon over a tap and fill it with water, letting the water inflate it. Add paint or glitter, then tie a knot in the end and place the balloon in the freezer overnight. When the water's fully frozen, remove the egg, and peel off the balloon skin.
Ask the child to wear protective glasses and let them carefully use a hammer to chip away the ice and release the dinosaur. This is best done outside. Instead of a hammer, you can use warm water to melt the ice.
2. Walking on Eggs
You'll need several large boxes of eggs. Just place the eggs in their boxes on the floor, making sure all the eggs are upright with the pointy end uppermost. In bare feet, stand on top of the eggs... and don't worry!
"They can hold up the weight of a fully grown adult without cracking," promises Urban.
"Your weight is shared between all the eggs you stand on; if your feet are each touching six eggs, then roughly speaking, each egg is carrying only one-twelfth of your weight. But an egg is shaped to be surprisingly strong if it is squeezed from the right direction. The two ends, especially the pointy one, are more curved, and they act like arches, which are very good shapes for sharing out a load, so that stress doesn't get concentrated at any point."
3. Balloon Light Switch
You'll need a balloon, a child's hair and a fluorescent light bulb.
Blow up the balloon and rub it for about 30 seconds on the child's hair so the hair sticks lightly to the balloon. Bring it very close to the bulb. You should see the bulb briefly flicker with light. This is clearest in a darkened room.
Urban says that when you rub a balloon against hair, you give it a charge of static electricity. The movement knocks little electrically charged particles called electrons out of the fibres, which can gather on the balloon and give it a charge. The fluorescent bulb works by an electric current flowing in the gas trapped inside the tube, and the charge on the balloon - when brought close to the tube - triggers the same process. But it only lasts for a flash, because the balloon quickly picks up particles with an opposite charge, so its static electrical charge is neutralised.
4. Oobleck Slime
You'll need two cups of cornflour, one cup of water and a large bowl.
Put the cornflour and water together in a big bowl - you can add food colouring too. Mix it up by hand, and if you still see dry cornflour, add a bit more water. If you scoop out a handful of oobleck and roll or squeeze it quickly in your hand, it sticks together like putty or clay. But as soon as you let it rest in your hand, it turns back into liquid and oozes through your fingers.
Urban explains that oobleck is an example of a 'shear thickening' liquid, meaning it gets thicker and more viscous when it's stirred, because tiny grains in the mixture get locked together when they're squeezed up against one another. If the squeezing happens slowly, they have time to move out of each other's way. But if it's too fast, they just get jammed.