Mix the Ingredients: In a bowl, combine 1 cup of baking soda, 1/4 cup of cornstarch, and 1/2 cup of water. Stir until it forms a goopy paste.
Color the Mixture: Divide the mixture into four bowls. Add a few drops of different food coloring to each bowl and mix well until the color is evenly distributed.
Prepare the Eggs: Place a small dinosaur toy inside a reusable water balloon. Fill both sides with the colored baking soda mixture and carefully close it. Repeat this process with additional water balloons and dinosaurs.
Freeze the Eggs: Once all the balloons are filled, place them in a bowl and freeze for at least 1 hour to harden.
Set Up the Fizzy Dinosaur Sensory Bin: Arrange your sensory bin with small bowls to contain the vinegar if you prefer a more controlled experiment. Place the frozen eggs in the bin or bowls as desired.
The Fizzy Reveal: Pour vinegar into a bowl and use eye droppers to invite your child to squeeze vinegar onto the eggs. Watch as the eggs fizz and dissolve, revealing the hidden dinosaurs inside!