Fun chemistry for the kitchen

By LES SAIDEL

MAY 21, 2020 13:38

‘WHAT IS Oobleck?’ you may ask. Why, a slimy green substance coined by Dr. Seuss! (photo credit: ANDREW CURRAN/FLICKR) — ‘WHAT IS Oobleck?’ you may ask. Why, a slimy green substance coined by Dr. Seuss!

(photo credit: ANDREW CURRAN/FLICKR)

There are amazing, fun and visually stimulating experiments you can do with simple baking ingredients, in your own home.

A bakery (or kitchen) is just a glorified chemistry lab, and there are amazing, fun and visually stimulating experiments you can do with simple baking ingredients, in your own home.

The first is the Baking Soda Volcano. The procedure is simple. Fill a regular drinking glass with a half a cup of vinegar. Place the glass in a larger Tupperware (to collect the overflow). To the glass with the vinegar, add a quarter of a cup of baking soda and stand back. The bubbling concoction will overflow like a volcano. The chemical reaction between sodium bicarbonate and acetic acid (vinegar) produces proliferate amounts of CO2 (carbon dioxide gas). For the more creative, you may construct a papier-mâché volcano around the glass with the vinegar.

Another variation on the theme is to fill a balloon with some baking soda (using a funnel). Fill a small water bottle with some vinegar. With the balloon folded so that the baking soda does not pour into the bottle, stretch the opening of the balloon over the opening of the bottle. Then lift the balloon and allow the baking soda to fall into the bottle. The balloon will inflate.

Next up is some craziness with Oobleck. What is Oobleck, you may ask. It is a name for a slimy green substance, coined by Dr. Seuss in his book Bartholomew and the Oobleck. So how do you make Oobleck? In a bowl, mix 2 cups of cornstarch (if you have any leftover potato flour from Passover that will also do) with 1 cup of water (and a drop or two of green food coloring – if you want to remain true to the good doctor). Oobleck is an interesting substance. If you squish it together quickly, it becomes solid, but let it alone for a few seconds and it liquefies. If you slowly insert your fingers in the slimy stuff it behaves like a liquid, but if you try and punch it with your fist, instead of your hand descending into the slimy depths it solidifies like a brick.

Scientists call this kind of fluid non-Newtonian, because it defies Newton’s law of viscosity having both liquid and solid properties, depending on how much pressure you apply. In Lamar University in Texas they made a huge bath out of the stuff that you could walk or jump on. Search Google for “Lamar University Oobleck bath.”

Let’s have some fun with water. Take two identical drinking glasses. Fill one to the top with ice-cold water and add some blue food coloring to it. Fill the second glass to the top with hot water (the temperature you would shower or bath with – not boiling). To the hot water glass add some red food coloring. Now take a playing card and cover the red/hot water glass. While pressing the card over the red glass, flip the red glass upside down and slowly slide it (with the card) on top of the blue/cold water glass. You now have the red glass upside down on top of the blue glass, separated by the playing card. Slowly slide the card out from between the two glasses.

Even though the red water and the blue water are touching, they miraculously remain in their own glasses and do not mix together, like magic. Now repeat the same experiment, except this time flip the blue/cold water glass with the card and place on top of the red/hot water glass. When you remove the card this time, the water in both glasses will mix together. The physics here is pretty simple – hot air rises and cold air sinks – same with water.

Finally, a great experiment with salt. Fill a glass three-quarters full with water. To that add a third of a cup of salt and stir until dissolved and the water is clear. Take a second glass and fill to the same level with only water, no salt. Take an egg and using a tablespoon slowly lower the egg into the glass with only water. The egg will sink to the bottom of the glass. Now take the egg and insert into the glass of salt water. The egg floats to the top in the glass with the salt! Here’s the science – the density of an egg is higher than that of water, so the egg sinks. When you add enough salt to the water you increase its density to higher than that of the egg, so the egg floats.

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There are a ton of similar fun experiments you can do with common ingredients in any kitchen that are visually stimulating and educational. Simply search online and you will find enough to keep the campers busy.

Stay well.

The writer, a master baker originally from Johannesburg, South Africa, lives in Karnei Shomron with his wife, Sheryl, and four children. He is CEO of the Saidel Jewish Baking Center (www.saidels.com), which specializes in baking and teaching how to bake healthy, traditional Jewish bread. He also manages the Showbread Institute (www.showbreadinstitute.org), which researches the biblical showbread.