Teaching Kids Science of Density at Home

Aug 26

With school a mere ten days away, I thought it an opportune time to get the boys back in the kitchen for some awesome science experiments. Because their days will soon be filled with desk-sitting, textbook-reading, don’t-raise-your-voice hours, I’d rather not pull out the curriculum-based workbooks to prep them for academics (just yet). I say let them have fun while they learn.. while they still can.

This first experiment called Liquid Layers (from the book Science Rocks!) is super easy. It helps kids understand the concept of liquid density and molecules.

You need: A tall clear glass, water, cooking oil, molasses, food colouring, and some a few different small object of varying weights (i.e. marble, strawberry, M&M)

Step 1: Pour water up to about one-third of the glass. Add food colouring. Then pour similar amounts each of molasses and cooking oil.

teach innovation

teach kids density

Step 2: Drop in the various solid objects and give it a good stir. (The kids love this part.)

science for kids

Step 3: Leave the glass for about half an hour, waiting until it settles into separate layers. Eventually three layers will appear, starting with the heaviest liquid (molasses) at the bottom, the water in the middle, and the oil on top. Notice where the objects sink. Lighter objects will float stop one of the higher layers, and heavy objects will sit at the bottom.

fun science for kids

Note to parents: This experiment left us with only two layers, which was slightly disappointing. The boys, however, had a blast pouring the liquids and still became familiar with the concept of density. I highly recommend this.

The second experiment we performed is called Float Your Boat (also in Science Rocks!) This also teaches density and is easy enough for a child as young as six to complete on his or her own (although it can get a bit frustrating for uncoordinated fingers.)

You need: marbles, bowl of water, modelling clay, and some patient encouragement for frustrated kiddos.

Step 1: Drop a marble into the bowl of water. Then drop the ball of clay. Notice that they both sink. (It gets better, I promise).

teach kids innovative thinking

Step 2: Remove the ball of modelling clay and press it out into the flat sheet. Then mold it into the shape of a small boat, making the sides high enough to prevent water leaking into them. (This is the part that can get quite frustrating for a child – namely a certain 12-year-old. You may need to help them, or show them how you do it on your own.)

science experiments for kids

Step 3: Put the newly constructed boat into the bowl of water. It should float. If it does not… back to the frustrating step 2 (which may need to be repeated several times if you have a stubborn child who refuses your help. Ah well) Once the boat is floating, place marbles one at a time into the boat.

kids science

Although this doesn’t sound particularly exciting, it is a lot of fun for kids to try to pile up the marbles before the boat sinks. By the end of the experiment, my kids had an understanding of how real boats are able to float, even though they are made of heavy materials.

Both experiments were virtually mess-free and required minimal supervision. Although they experienced frustration during the process, this is actually a good thing. It helps them recognize that a big part of experimentation is making mistakes… and having to start all over again.

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Experiment Lets the Kids Get Messy: Learning About Catalysts

May 08

This is week 2 of my journey into the world of kids’  innovation and science. We’re back in the kitchen making goop (my kids like getting messy.) This particular experiment helps kids understand propulsion through the use of . Rocket fuel, for instance, is created when a catalyst is added to concentrated hydrogen peroxide and is used in jet packs to propel humans through the air.

But don’t worry – no kids will be flying across your kitchen.

Today’s experiment is called Elephant’s Toothpaste (don’t ask why, ’cause I don’t know).

It is taken from the book Science Rocks! by Ian Graham. (I highly recommend this book.)

Ingredients: empty plastic bottle, hydrogen peroxide, dishwashing liquid, food colouring, dry yeast, hot water, funnel, baking tray.

First - Measure 4 oz of hydrogen peroxide and pour into the bottle (which should be set upon the tray to minimize the cleaning later!) Then add a few drops of food colouring and a few drops of dishwashing liquid.

Let the kids do the measuring.

My boys chose pink dye.

A few drops of dishwashing liquid will do

Second - Mix a teaspoon of yeast with two tablespoons of hot water in a cup or bowl, then pour it through the funnel into the bottle. My kids thought it’d be fun to add some figurines into the mix, too.

Third - STEP BACK!

This kind of experiment is just what the boys love

Time to get the hands into it

I highly recommend this science experiment. It’s a big step up from the old  baking soda and vinegar trick and not a whole lot more work. As long as parents keep the mess contained within a baking tray, the clean up is swift, too. And by the way, I’d encourage you to include clean-up as part of the kids’ experiment (especially when the dishwashing liquid is so handy.)

Related Posts:

The Science of Slime for Innovative Kids

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Kids Can Be a Scientist in 3-Minute Video for $250 Prize

Feb 21

Parents and kids! This very cool contest, sponsored by invites kids to create their own YouTube video that explores an important issue facing society today. It can relate to health, the environment, world hunger, or any other issue that you think is important.

Just come up with a problem. Turn it into a question. And brainstorm your own solution. Then, through a 3-minute video, propose a creative, original  and scientific solution to your problem. This fun project is a great opportunity to encourage innovative thinking and inquiry-based scientific learning. And, best of all – it makes science fun!


Kids must be between the ages of 6 and 18 years old. The finished video must be uploaded with the title “2012: Science Can Fix That” onto YouTube by March 31st, 2012.

The video entries received are judged based on: concept originality; quality of the solution to the problem; creativity and imagination; scientific truth, ability to inspire; and adherence to the contest rules.

More about the contest is .

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