Kid's Science Experiement

Photo by Andrew Curran

The Science in Action! team of Gonzaga professors and students invite you to bring the lab into your own home with these fun family science experiments!

Learning Objective: To discover how much salt it takes to change the density of tap water enough to cause an egg to float!

Supplies:

  • A clear cup or glass
  • 1 fresh, raw egg
  • Salt
  • A bowl
  • Measuring spoons

Instructions

  1. Make a data sheet to record the amount of salt you add at each trial.
  2. Fill a clear glass about 3/4 of the way full with tap water.
  3. Place an egg in the water and make initial observations. Remove egg and place in bowl between trials.
  4. Ask your young scientist to decide an initial amount of salt to add. Add the salt to the water and stir to dissolve. Place the egg back in the water.
  5. Based on this initial observation ask your scientist to make a prediction of how much total salt (tablespoons) it will take to make the egg float.
  6. Continue incrementally adding salt until the egg floats!

The Science

This experiment explores the concept of density. Density is a measure of how compact something is (how much “stuff” or matter is packed into the space). Mathematically density is the ratio of mass to volume for an object or substance. A great way to visualize this is compare two things that are the same size, like a ping-pong ball and a golf ball, but are different densities. You can also teach your scientist to draw 3D cubes!

 
A great sensory lesson for ALL ages! Ooblek is a Non-Newtonian fluid that has the properties of both a solid and a liquid.

Supplies:

  • 16 oz box cornstarch
  • Large Tupperware
  • Water
  • Measuring cup
  • Food coloring (optional)

Instructions

  1. Ooblek is a ratio of 2:1 (two parts cornstarch to one part water)
  2. Place cornstarch in a large tupperware and then add water and stir.
  3. Start with . cup of water for a 16oz box and continue adding water until you reach the right consistency: You are looking for a consistency where the ooblek becomes firm or hard when you squeeze it, but will instantly become liquid and runny when you stop applying pressure to it.
  4. Add a few drops of food coloring for extra fun!
  5. Things to do: Try making a ball and passing it to someone else, poke it, run your hands through it, pick some up and watch it drip down, drop marbles into it, watch YouTube videos of people walking across it!

The Science

A Newtonian fluid has a constant viscosity, such as water or even cooking oil. A Non-Newtonian fluid -you guessed it!- changes viscosity when you apply a force (shear stress) to it. Ooblek becomes thicker when you apply force, making it act more like a solid. Ketchup is also a non- Newtonian fluid, but it becomes thinner!

 
Learn more about Gonzaga’s Science In Action! Program