Category Archives: Science Projects

Cool Electroactive Slime That Reacts to Styrofoam

Electroactive slime is a opaque slime that reacts to static electricity. (Josh Hallett)

Electroactive slime is a opaque slime that reacts to static electricity. (Josh Hallett)

This recipe makes cool, non-toxic slime that appears to have a life of its own! It’s electroactive slime, so it reacts when it’s close to electrically charged objects. Rub a piece of polystyrene foam or a balloon on your hair or a wall to charge it and observe how the slime reacts.

Difficulty: Average

Time Required: 30 minutes

Electroactive Slime Materials

  • 3/4 c cornstarch (175 mL)
  • 2 c vegetable oil (475 mL)
  • glass or tumbler
  • refrigerator
  • 1x6x6 inch (25x150x150 mm) styrofoam

How To Make Electroactive Slime

  1. Mix the cornstarch and vegetable oil together in the glass.
  2. Refrigerate the slime mixture until it is chilled.
  3. Remove from the refrigerator and stir (separation is normal).
  4. Allow the mixture to warm enough so that it can flow.
  5. Take a block of styrofoam and charge it by rubbing it on hair, wool, or a cat.
  6. Tip the container of slime (which should flow slowly). Place the charged styrofoam about an inch (2 cm) from the flowing slime. It should stop flowing and seem to gel!
  7. If you wiggle the charged styrofoam the slime may follow or pieces of it may even break off.
  8. When the styrofoam is removed the slime will continue to flow.
  9. After use, refrigerate slime in a sealed container.

Be sure to try other slime recipes, too!

See Electroactive Slime in Action

Here’s a variation of the recipe that shows how the slime reacts with static electricity. If she had refrigerated her slime, it would be more “slimy”. The slime has a life of its own whether it’s chilled or not:

Super Easy Soap Slime Recipe

Use translucent glycerin soap to make soap slime you can see through. (darwin Bell)

Use translucent glycerin soap to make soap slime you can see through. (darwin Bell)

Soap slime is an easy-to-make type of slime that is fun to play with and makes clean-up fun. Here’s how you make it.

Soap Slime Materials

  • leftover pieces from bars of soap (or you can use a whole bar)
  • water
  • jar

Make Soap Slime

You’ve probably made soap slime accidentally by allowing soap to get wet and stay wet in the bathtub or shower. Here’s how you make soap slime, on purpose:

  1. Place the soap pieces in a jar.
  2. Cover the soap with water.
  3. Let the jar sit for a day or two. You’ve got slime!

You can play with the slime or you can use it during bath time like you would ordinary soap. The soap slime with rinse away with water. Soap isn’t edible, so don’t eat this slime either. Also keep it out of your eyes. If you get some soap slime in your eyes, immediately rinse it out with water. Otherwise, have good clean fun!

Make Dish Soap Slime

Another cool type of soap slime to make uses dish soap. The ingredients for this slime are:

  • liquid dish soap (choose the color you want the slime to be)
  • glitter
  • clear non-toxic glue (PVA or polyvinyl alcohol school glue)
  • salt water or saline solution (although you’ll get better results using borax in water)

Make a Color Change Liquid Thermometer

Cobalt(II) chloride may appear either pink or blue in solution, depending on which ion is formed. (Chemicalinterest)

Cobalt(II) chloride may appear either pink or blue in solution, depending on which ion is formed. (Chemicalinterest)

This color change chemistry project will give you a liquid that fluctuates between pink and blue as the temperature changes. In essence, it’s a color change thermometer.

What You Need

  • beaker or attractive clear container
  • 3 g cobalt(II) chloride hexahydrate (also known as cobaltous chloride hydrate)
  • 500 ml alcohol

Prepare the Solution

  1. Mix 3 grams of cobalt(II) chloride hexahydrate in alcohol.
  2. The pink solution will turn blue as it is heated and will return to the pink color as the solution cools.
  3. Alternatively, heat the solution until it it is just slightly warmer than room temperature. Add water dropwise until the blue solution turns pink. This solution will be extremely sensitive to color changes near room temperature.

How It Works

Aqueous solutions of hydrated cobalt chloride are pink, but formation of [CoCl4]2- produces a blue color. Addition of hydrochloric acid to an aqueous cobalt(II) chloride solution will change the solution from pink to blue as will temperature change of the alcohol solution. This presumably occurs because the amount of water attached to the cobalt ion changes as you vary the temperature of the alcohol solution.

Rainbow WandMake Violets Change Color

Pull a Wire through an Ice Cube – Science Project

You can pull a length of wire through an ice cube thanks to the process of regelation. (Anne Helmenstine)

You can pull a length of wire through an ice cube thanks to the process of regelation. (Anne Helmenstine)

Pull a wire through an ice cube without cutting the cube! This trick works thanks to a phenomenon called regelation, in which the ice melts from the pressure of the wire and freezes up after the wire passes. Here’s how to put a wire through an ice cube or hang the ice on wire.

Ice Cube on a Wire

Cut a length of fine wire. Wrap each end of the wire around a pencil to give yourself handles for the wire. Place the wire on top of an ice cube. Pull on the pencils to melt the ice below the wire. You can speed the process by applying a sawing motion to the wire. Either leave the wire partly in the ice or pull the wire all the way through the ice. As the wire passes through the ice, the cube will refreeze. The ice cube won’t be cut. In fact, you probably won’t even see the line where the wire went through the ice.

Ice Cube Illusion Necklace

An alternative is to use clear nylon fishing line instead of wire. It takes a little more pressure to melt the ice cube under the pressure of the fishing line, but you’ll get a clear ice cube on a clear line — an ice cube illusion necklace!

Boil Water in a Paper Bag – Science Project

Paper is a poor conductor of heat, so if you heat a bag of water over a flame, it won't burn, but the water will boil. (Jeffrey Beall)

Paper is a poor conductor of heat, so if you heat a bag of water over a flame, it won’t burn, but the water will boil. (Jeffrey Beall)

Here’s an interesting project for you to try: boil water in a paper bag.

Boil Water in a Bag

  1. Place a ring stand over a Bunsen burner. That’s right, we’re going to boil the water in the paper bag over an open flame! Alternatively, you can make a box using printer paper and either paper clips or Scotch tape.
  2. Place a screen on the ring stand. This will help to evenly distribute the heat from the flame.
  3. Add about 200 ml of water to a small paper bag (about 4-6″ across) and place the bag of water on the screen over the burner flame.
  4. Wait for the water to boil.

How It Works

Paper is a poor conductor of heat so the water heats slowly. Conduction of heat through the paper eventually increases the temperature of the water to its boiling point. The heat keeps the water from seeping through the bag, while the high heat capacity of the water keeps the paper from igniting.

Boil Water in Other Materials

You can boil water in other surprising containers. A good example is a paper cup. It’s also possible to heat water inside a balloon without popping it…

Make a Safe Homemade Lava Lamp

You can make your own lava lamp using safe household ingredients. Anne Helmenstine

You can make your own lava lamp using safe household ingredients. Anne Helmenstine

Lava lamps are interesting and cool. Have you ever wanted to make your own cool oozing display? Lava lamps that you buy use high heat and toxic chemicals, but you can make a lava lamp at home using safe kitchen ingredients. Here’s how:

Materials

This project results in a non-toxic lava lamp that is safe for kids to make and use.

  • 1-liter plastic bottle
  • vegetable oil
  • water
  • food coloring
  • Alka Seltzer tablets

Make a Lava Lamp

  1. Fill the bottle most of the way full with vegetable oil.
  2. Add about a tablespoon of water.
  3. Drip in a few drops of food coloring.
  4. Break an alka seltzer tablet into pieces and add them to the bottle.
  5. Seal the cap on the bottle.
  6. After the reaction is complete, you can break and add another alka seltzer tablet to make more bubbles.
  7. Feel free to shine a flashlight on the bubbles to add the ‘light’ part of a traditional lava lamp.

I made a lava lamp video of this project so you can see what to expect.

Volcano Cake Decorating Instructions

Add a little water to dry ice to make a smoking volcano effect on a cake. You can use red jello or tinted icing if you want 'lava' to flow down the sides of the cake.

Add a little water to dry ice to make a smoking volcano effect on a cake. You can use red jello or tinted icing if you want ‘lava’ to flow down the sides of the cake.

It’s easy to decorate a volcano cake. This is a great party cake for birthdays or a mad scientist theme party.

Bake the Cake

  1. Select your favorite cake mix. Red velvet cake probably looks the most like molten lava, but you can use any flavor. You can get a nice effect by adding red food coloring to a yellow cake mix. Preheat your oven (350° F). 
  2. Spray a glass or metal 2-qt mixing bowl with nonstick cooking spray. 
  3. Sprinkle the pan with flour. Shake out any excess. 
  4. Bake the cake. It will take about as long as if you were baking a bundt cake… probably around 35 minutes. 
  5. Allow the cake to cool completely. 
  6. Remove the cake from the bowl and set it on a plate. If the cake sticks, you can use a rubber spatula or butter knife to help release it.
It's easy to decorate a cake to resemble a volcano.

It’s easy to decorate a cake to resemble a volcano.

Decorate the Volcano Cake

  1. There are two ways to go here. If you have access to dry ice, you can hollow out the top of the cake to accommodate a small cup and frost all around the cup. When it’s time to serve the cake you would add a little hot water to the cup and drop in a bit of dry ice. This makes a spectacular display! (Here’s a video of what to expect.) You can use colored icing or red jello instead of water if you want lava to run down the sides of your cake. If you don’t have access to dry ice you can use lava-colored fruit roll-ups to simulate an eruption. It’s not as cool-looking, but it tastes great. 
  2. Frost the cake with chocolate frosting. If you like, you can stir in a little red and yellow food coloring to give it more of a red-hot look. If you don’t like chocolate, you can swirl lava colors into vanilla, cream cheese, or lemon frosting. 
  3. Use orange frosting to make rivulets of lava running down the sides of the cake. 
  4. Sprinkle red crystal sugar onto the orange lava to give your cake a red-hot glow. 
  5. To make a fruit roll-up eruption, unwrap two lava-colored fruit roll-ups. Fold them in half and re-roll them. You may want to tear the edges of the fruit to make them jagged. Set the fruit roll-ups into the frosting on the top of the cake.

Make the Volcano Cake Really Erupt

A simple way to make the cake smoke and appear to erupt is to set a small container of warm water on top of the cake. Add a pellet of dry ice when it’s time to serve the cake. If you want flowing lava, substitute syrup dyed with red food coloring for the warm water. If you fill the container completely full and add the dry ice, the lava will flow down the side of the cake.