Science Project Holiday Gifts – Sidewalk Chalk

    Published: 06-16-2009
    Views: 15,464
    Mary Porter Green from Curiosity Zone demonstrates how to make sidewalk chalk for the holidays.

    Mary Porter Green: Hi! I am Mary Porter Green from Curiosity Zone. Today we are doing great science experiments that you could do at home with your kids in the kitchen or in the class room that actually make great holiday gifts. For our next experiment, we are going to make holiday side-walk chalk and we are going to make them in these fun, cool shapes that kids will love to play with. For this experiment, you are going to need Plaster of Paris, water, powdered tempera paint, little bit of glitter and a cookie cutter, and that should get you all set.

    This is a very simple experiment but it's a very interesting scientific experiment because most kids think of solids turn into liquids and liquids turn into solids because of a temperature change. But in this reaction, you are going to combine two things that are actually through a chemical reaction go from being kind of a slushy solution into a solid in a relatively short period of time.

    What's also interesting is as the chemical reaction occurs it actually gives off heat which is called an exothermic reaction. And so as so it's turning into a solid, it actually gets a little bit warm which is really kind of cool. So super simple experiment.

    This is a third of a cup of Plaster of Paris. You put this into a cup and then you are going to add a table spoon of water and then a second table spoon of water. And then you are going to one tablespoon of your powdered tempera paint and you can use any color you want. Be as creative as you want.

    We decided to use kind of a cool blue color, kind of an icy blue, holiday color. So you put that in your cup as well and then you stir until you get to a nice pasty form. And if you are doing this with little ones you want to make sure that they are very careful as they stir this and they get it to the right consistency and the right -- you know you have done it right when the consistency is kind of like runny peanut butter. And for whatever reason it sometimes varies, sometimes you have to add a little bit more water. I think I am going to add a little bit more water to this.

    Basically what you end up with is kind of a sloppy-gloppy almost like a paste, almost like runny peanut butter. And what you want to do is take this and drop it into your cookie cutter, a little bit at a time. And obviously if it's too runny, it will start to run out at the bottom of the cookie cutter. You want to make sure you got it the right consistency.

    And you press it in there, be sure you get it nice and -- pressed in there so it'll be nice and smooth. And also if it does start to run up the sides, one thing you can do is take a plate and press down on it until it starts to become a solid and it'll will start to become a solid very quickly within probably 4-5 minutes.

    Anyway, before you set it aside to harden, you want to add a little bit of holiday, fancy holiday glitter. Sprinkle that on top and then you just want to set it aside to dry. It will -- and actually technically it's not drying, it's hardening through a chemical reaction. And when it's finished, you will be able to pop it out and you have got fabulous holiday chalk.

    A wonderful way to make these into holiday gifts is to do a different colors and use different cookie cutters and make a whole set of really cool holiday chalks in all different shapes and colors. Then wrap them up in a pretty little bag and give them to a kid to go play with them on the sidewalk or on a black board.

    I hope you have a great time this holiday season, doing science projects with your kids in the kitchen, exploring chemistry, learning all about the science in your everyday world and making some fabulous holiday gifts. Thanks for watching!