1. Balloon Rocket: Inflate a balloon and attach it to a string between two chairs. When you release the balloon, it will move forward due to the air escaping from it.

2. Dancing Raisins: Drop a few raisins in a glass of soda and observe how they dance up and down due to the carbon dioxide bubbles.

3. Volcano Eruption: Create a volcanic eruption by combining baking soda and vinegar. Watch as the mixture bubbles and foams, resembling a real volcano eruption.

4. Rainbow in a Jar: Carefully layer different colored liquids with different densities, such as honey, dish soap, and water, in a clear jar. This creates a colorful rainbow effect.

5. Invisible Ink: Write a secret message using lemon juice as invisible ink. When heated, the message will appear, revealing your hidden message.

6. Eggshell Geodes: Dissolve sea salt or Epsom salt in warm water and let it soak into eggshells. After a few days, colorful crystals will form inside the eggshells.

7. Static Electricity Butterfly: Cut out a butterfly shape from a coffee filter or tissue paper. Rub a balloon against your hair or clothing to create static electricity, then place the balloon near the butterfly. Watch it stick to the balloon!

8. Shadow Hand: Using a strong light source and a white wall, position your hand between the light and the wall. Observe the shadow created on the wall and try to make various shapes with your hand.

9. Magic Milk: Pour a shallow layer of milk in a dish and add a few drops of different food coloring. Dip a cotton swab in dish soap and touch it to the milk. Watch as the colors swirl and
mix together.

10. Floating Eggs: Fill a glass with water and add salt until the egg floats. Experiment with the saltwater concentration to see how it affects the buoyancy of the egg.

11. Bending Water: Turn on a tap so that a thin, continuous stream of water flows. Rub a comb against your hair to create static electricity, then bring the comb near the water stream. Observe how the water bends towards the comb.

12. Walking Water: Place three cups next to each other, half-filled with water. Add different food coloring to each cup. Connect the cups using pieces of paper towel, and watch as the colored water travels through the paper towel, creating a rainbow effect.

13. Invisible Glass: Fill a glass with water and add a few drops of cooking oil. Observe how the oil makes the glass appear invisible and distort the objects behind it.

14. Egg Drop Challenge: Design and build a contraption using only straws and tape to protect an egg from cracking when dropped from a certain height. Test different designs to see which one is the most effective.

15. Homemade Lava Lamp: Fill a clear bottle with water and vegetable oil. Add a few drops of food coloring and an Alka-Seltzer tablet. Observe the colorful bubbles rising and sinking, creating a lava lamp effect.

These science experiments and activities are not only fun for fourth graders but also help them learn important scientific concepts through hands-on exploration. Enjoy conducting these experiments and discovering the wonders of science!