Nurture for the Future

Simple Science: Coke-Mentos Explosion

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#weekendfun #scienceexperiment the mentos explosion. Gotta admire the artistry.

This is a very easy experiment and one that all kids love. It’s messy so best to do it outside. There are also lots of variations you can test out:

  • Diet versus normal soft drink
  • Coke versus other soft drinks
  • Mentos versus other sweets

Hint: for the biggest explosion use diet soft drink and fruit Mentos.

The Science Behind It

The Coke and Mentos experiment is a popular one that has loads of youtube videos on it. The following is a great one explaining what’s happening:

What’s happening?

Water molecules like to be next to other water molecules, so basically anything that you drop into the soda that disrupts the network of water molecules can act as a growth site for bubbles. And if you have rough candy with a high ratio of surface area to volume, then there’s more places for the bubbles to go. – Tonya Coffey

Diet works best because it contains Aspartame

Greatest reaction was with Diet Coke and Coke Zero because they both contain the artificial sweetener – Aspartame. This is because Aspartame lowers the surface tension of the drink, making it easier for the bubbles to form. This allows the reaction to take place more quickly. You will notice in the video above, the experimenter hardly has any time to drop the Mentos sweets before the liquid erupts.

Chemical or Physical?

Contrary to some explanations, this is not a chemical reaction but a physical one. Lots of speculation on the internet suggest that it is an acid-base reaction, again this is incorrect. A test of pH at the end of the experiment reveals that the soft drink’s pH is not altered by the reaction. Additionally, there are no ingredients that provide the “base” in an acid-base reaction.

Why does Mentos work better than other sweets?

Soft drinks are fizzy because carbon dioxide has been dissolved into the liquid under pressure. When you open a can or bottle of soft drink, the carbon dioxide in the drink slowly rises to the surface and escapes. By adding Mentos, we make this reaction occur more quickly because the rough texture of the Mentos provides nucleation sites for the carbon dioxide bubbles to form. Mentos works better than other sweets because it’s heavy and falls to the bottom more quickly. Additionally, Mentos sweets contain a sugar coating that further reduces the surface tension of the drink, facilitating bubble formation.

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Science Experiments: DIY Volcano

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Science is not only an important subject for kids to learn but it can also be extremely fun for the family to learn together – especially when you’re working with experiments of an explosive nature… One of the simplest science experiments that kids love to do is the volcano science experiment. Here’s how you can do it at home…

Volcanoes: Fun Facts for Kids

But first, let’s learn a little bit about volcanoes…

  • There are about 1,900 active volcanoes on the earth – this means they have erupted recently or they might erupt.
  • Some volcanoes are extinct.
  • Over 80 volcanoes have been found in the ocean.
  • Most volcanoes happen on fault lines, or cracks in the Earth’s surface.
  • Most of the earth’s volcanoes are in the Pacific Ocean, in an area called the Ring of Fire.
  • The word “volcano” comes from Vulcan, the Roman god of fire.
  • Lava from volcanoes can reach temperatures of 2,000 degrees Fahrenheit.
  • Volcanoes spew out ash and toxic gases, as well as lava and lava boulders.

Learn more about volcanoes in this video from SciShow:

Science Experiment: Make Your Own Volcano

Making a volcano is a fun and easy science experiment you can do at home with explosive results (pun intended).

In the video above, the kids are using a volcano kit from The Magic School Bus Science Club (which you can also get from here if you live outside US/Canada).

However, you can also make your own volcano from materials easily found at home. Here’s what you’ll need:

  • vinegar
  • six drops of dish washing detergent
  • an empty, plastic bottle (500ml)
  • 2 tbsp baking soda
  • red/orange/yellow food colouring
  • a funnel

Method:

  • fill your bottle with water (7/8 full) and add food colouring
  • add dish washing detergent
  • add baking soda (using the funnel so you don’t spill)
  • lastly, add the vinegar to the bottle and watch your volcano erupt

If you want the full volcano effect, you can make a dough to pack around your plastic bottle so it looks more like a volcano. Here’s the recipe:

  • 6 cups flour
  • 2 cups salt
  • 4 tbsp oil
  • 2 cups water

Mix everything together and knead it into a workable consistency. Pack the dough around your plastic bottle, shape it to look like a volcano, and you’re good to go…

What’s Happening in this Experiment?

Baking soda, also known as sodium bicarbonate, is a base and vinegar is a dilute form of acetic acid. So what you have is essentially an acid/base reaction with carbon dioxide gas as one of the end products. The carbon dioxide escapes the solution as bubbles, and the bubbles, being heavier than air, collects at the surface of the container and causes it to overflow. The addition of dish washing detergent is to collect the gas and form bubbles that flow in an manner similar to lava running down the side of a volcano.

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Simple Science: 3 Cool Bubble Experiments

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Too awesome! We gotta try this – especially the neon one since the boys are so into “glow in the dark” stuff these days…

There’s not a lot about the science behind it on the video, so here are the links if you want to look them up…

How does highlighter ink make the bubbles glow in the dark?

Some highlighters use ink that contains dyes that are fluorescent. The dyes in the highlighter ink require a black light (UV – ultraviolet light) to produce the special glow.

From Steve Spangler Science:

  • Phosphorescence – when an object glows in the dark when the lights are off.
  • Fluorescence – when an object glows under a ultraviolet light
  • Chemiluminescence – when an object glows as a result of a chemical reaction between different chemicals

Also Steve Spangler recommends using tonic water for glow in the dark bubbles because it’s safer (should also check out his warning on using the wrong chemicals for glow-in-the-dark experiments).

Don’t miss this one either – more things that glow in the dark…

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Simple Science: How Plants Absorb Water and Nutrients

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We had excess food dye left over from our Advanced Potion Making Class so we decided to try the coloured-water absorption experiment with cabbage leaves. You can use other plants, like celery or flowers, but the effect is clearest when you use a light coloured plant, like chinese cabbage or white daisies. We didn’t have easy access to white flowers so we used chinese cabbage.

What you will need:

  • chinese cabbage
  • three containers
  • water
  • food dye – we used blue, red and yellow

Add a little food dye to each container and dilute with water. Place one cabbage leaf in each container. Wait and watch.

Plant science - cabbage colour change

Our food dye colours from left to right: red, yellow, blue. I know the yellow looks orange but it really is yellow food dye. Watch the colour spread as the liquid is absorbed up through the cabbage leaf. To get a better effect, leave your experiment overnight and check in again the next morning.

Plant science - cabbage colour change

This simple experiment is a terrific illustration of how plants take in water and nutrients up through their stems. You can also try this with flowers – the effect is quite lovely.

You can also watch this experiment, complete with explanations, in the following video:

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Simple Science: Magic Cornflour Mud, Oobleck, and Non-Newtonian Fluids

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Borrowed another idea from G2’s class yesterday…

Magic Cornflour Mud

The recipe I borrowed from Scientific American:

  • 1 1/2 cup cornstarch
  • 1 cup cold water
  • Food colouring

The intention was to make brown mud, but what d’ya know… I bought two bottles of blue food colouring instead of one blue and one yellow. Since I only had blue and red food colouring, we ended up with purple mud… The mixing process is kinda cool – the colours look awesome!

Magic Cornflour Mud

G2 had fun exploring the texture of his magic mud, better known scientifically as oobleck. Aside from all the fun you can get out of it, oobleck is also a great way to teach children about the properties of non-Newtonian fluids. Quicksand and silly putty are two other examples of non-Newtonian fluids.

Oobleck is a non-Newtonian fluid, which means that, unlike regular liquids, its properties are pressure-dependent. If you apply pressure, it increases its viscosity (thickness). A quick tap on the surface of Oobleck will make it feel hard, because it forces the cornstarch particles together. But dip your hand slowly into the mix, and see what happens—your fingers slide in as easily as through water. Moving slowly gives the cornstarch particles time to move out of the way. – Scientific American

Magic Cornflour Mud

It was fun for a while until G1 came along and complained about the smell. Something about the cornstarch mixture did not agree with his olfactory senses. Ever impressionable, G2 eventually agreed that it did not smell nice. Ah well… so we cleaned him up and whoops! We have a smurf! Guess our food colouring dose was a little too strong. It came off in the end though.

Magic Cornflour Mud

Here’s more about the science of oobleck from The Myth Busters – pretty cool “walking on water” stunt:

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Simple Science: Dilatant Materials – Silly Putty and Melting Martians

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The boys received Melting Martians for Christmas…

It is a surprisingly simple idea but it has kept the boys entertained for a lot longer than I would have expected. It’s also neater and cleaner than Play Doh – I wonder if we can get more of this stuff from somewhere…?

Here’s how it works:

You build a Martian with the putty and plastic parts.

Melting Martians

The boys have let their imaginations run wild with their creations…

Melting Martians

Then leave it for a few minutes and the Martian will “melt” as the putty loses its shape.

Melting Martians

It’s a neat way to teach the kids about the cool and unique properties of Silly Putty, which is a dilatant (also referred to as shear thickening) material:

  • you can stretch it without tearing it, although you can break off bits of it easily
  • if you throw it against the floor, it will bounce
  • it will keep its shape when you hit with a hammer, but you can squish it in your palm to change its shape

Did I also mention how much fun they have with it?

Make Your Own Silly Putty

Here’s a recipe from YMC (Yummy Mummy Club):

  1. Mix 250 ml of hot water with 7 ml of borax powder until all the borax dissolves. Set this solution aside.
  2. Get a cup and mix 30 ml of Elmers Multi-purpose Glue with 20 ml of water.
  3. Add two or three drops of food colouring to the glue/water mixture.
  4. Once the glue, water, and colouring is mixed together well, add 20 ml of borax solution. Stir this all together.
  5. Take the mix out of the cup and knead it. Be sure to pop all of the bubbles of glue. More borax solution can be added if it is very gluey. Knead it until it has a consistent texture. You now have silly putty!

You can also try this recipe from PBS:

  1. Mix Elmers Multi-purpose Glue with the food coloring until the color is even throughout.
  2. Pour Sta-Flo concentrated liquid starch into the colored glue mixture.
  3. Stir and let it sit for five minutes.
  4. Pull the putty out of the mixing bowl and set it on a paper towel. Knead the putty in your hands for five to ten minutes.

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