Easy Science Experiments : Secret Messages

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We love easy science experiments and this one falls under the category of Kitchen Science Experiments as well, using ingredients we already had on hand in the kitchen. We painted secret messages and pictures, then revealed them in just a couple of minutes. I’ll explain the science behind the experiment in just a moment. 

kitchen science experiments

 

You will need:

  • 4 teaspoons table salt
  • 1/3 cup of water
  • paint brushes
  • black paper
  • an oven

The Experiment

Mix the salt and water together.

Paint onto the paper. Try to scoop as much salt onto your brush as you can. The more salt, the more vivid your message or picture will be. Stirring the salt between brush strokes helps, as the salt tends to settle in the bottom of the bowl. 

On an oven rack placed in the middle of your oven, bake at your oven’s lowest temperature (150 to 200 degrees Fahrenheit). Place the paper right on the oven rack (grown-ups should do this part) for 2 to 3 minutes. Since this is so fast, kids can watch through the oven door and see the message appear. You can leave the paper in another 2 minutes if it needs to dry more. The more water used, the longer it will need to dry.

After further drying for an hour or so on the counter, the messages and pictures were even more vivid. 

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The Science Behind It

The water evaporates, leaving the salt behind. The warm oven speeds up the evaporation process. Evaporation is when a liquid changes to a gas. Liquid molecules are always in motion. When the liquid molecules rise with enough speed, they break through and become gas molecules. 

kitchen science experiments

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