Try these experiments and observe what happens. Then try to guess why it happens. Compare your results to the results lower on this page.
How? Mix one and one half cups of cornstarch with one cup of water in a bowl. Slowly dip your finger into the gooey mixture; then try slapping it hard with your hand or a heavy spoon. What happens? Why?
How? Place a short candle, a slightly taller candle, and a small dish or small glass filled with baking soda in the bottom of a large bowl. Light both candles. Then pour vinegar into the dish of baking soda. Observe the foaming reaction. What happens to the candles? Why?
How? Pour one-third cup of syrup into a glass jar followed by one-third cup of cooking oil. Then pour in one-third cup of water. Drop in a piece of plastic, followed by a grape, followed by a small cork. What happens? Why?
How? Fill a glass or bottle half full with carbonated water. Drop three to four raisins into the water. Wait. What happens? Why?
How? Fill a plastic bottle with water. Attach a small piece of clay on the arm of a plastic pen cap. Place the cap in the bottle so it floats and seal the bottle tightly. Squeeze the sides of the bottle. What happens? Why?
How? Drop three lit matches into a glass bottle that has a narrow neck (an apple cider jug works well). Quickly place a peeled, hard-boiled egg on the mouth of the bottle. What happens? Why?
The molecules in ooblekh are very large compared to, for instance, molecules of water. When slapped quickly, they entangle themselves preventing any splattering. In this way the mixture behaves more like a solid.
The liquids have different densities. The most dense (syrup) will be at the bottom, the least dense (oil) will be at the top, with the water in between. Each object will sink to the level of the liquid that has a greater density than the object. The object will then float on that layer.
When vinegar reacts with baking soda, carbon dioxide gas is produced. This gas is heavier than air so it sinks to the bottom of the bowl and slowly begins to fill up the bowl as though it were water. When the level of carbon dioxide has risen to the level of the flame, the flame will go out from lack of air.
Carbonated water contains dissolved carbon dioxide gas that collects on the irregular surfaces on the raisins. Once enough gas has collected, it will actually lift the raisins to the surface where the gas is released into the air, causing the raisins to sink once again.
By squeezing the bottle, you increase the pressure inside, thus forcing more water up into the pen cap. The added water in the cap increases its weight and causes the cap to sink.
The flames heat the air in the bottle. As the heated air expands, some of it escapes out the bottle. When the matches go out, the air inside the bottle cools and contracts, thus creating a lower pressure inside the bottle than outside. The greater pressure outside the bottle forces the egg into the bottle.