Hooked On Science: Floating Water
- PLEASE follow these safety precautions when doing any science experiment.
- ALWAYS have an adult present.
- ALWAYS wear the correct safety gear while doing any experiment.
- NEVER eat or drink anything while doing any experiment.
- REMEMBER experiments may require marbles, small balls, balloons, and other small parts. Those objects could become a CHOKING HAZARD. Adults are to perform those experiments using these objects. Any child can choke or suffocate on uninflated or broken balloons. Keep uninflated or broken balloons away from children.
- Transparent Plastic Cup
- Large Index Card
STEP 1: Fill the transparent plastic cup ¾ of the way with water.
STEP 2: Place the large index card over the top of the cup.
STEP 3: Carefully turn the cup upside down, holding the card in place, remove your hand from the card, while still holding the cup, don’t squeeze the cup, and observe. Compare the effects of different strengths and different directions of pushes and pulls on the motion of the card. Provide evidence of the effects of balanced and unbalanced forces on the card.
A higher air pressure, on the outside of the cup, is pushing harder on the large index card, overcoming the force of the water pushing down and the lower air pressure, inside the cup, keeping the card in place. The card doesn’t slide thanks to surface tension and adhesion.