We taped a straw on a plastic bag and threaded a string through the straw. We tied the string to chairs and stretched it tightly between them. We put the bag next to a chair with the open end facing the chair. We blew up a balloon and put it in the bag while holding the neck of the balloon closed to keep the air inside. Then we let go of the balloon and watched it race toward the other chair. This demonstrated Newton’s Third Law of Motion. The action was the air rushing out of the balloon and the reaction was the balloon rushing off to the other side of the room.
We made a blender using the the K’Nex Gears Kit.
We poked a hole through a 2-liter soda bottle and put a straw through it, sealing around the hole with modeling clay. We poured some vinegar into the bottle and wrapped baking soda in a tissue. We pushed the baking soda into the neck of the bottle and capped it. Then we tilted the bottle so the tissue and baking soda got soaked by the vinegar and quickly placed the bottle in a tub of water with the straw facing down. The soda bottle boat propelled itself around the tub demonstrating Newton’s Third Law (action: carbon dioxide gas coming out of the straw; reaction: the “boat” sped forward).
We made three same sized balls out of modeling clay. Cameron dropped one from the highest point, Fritz dropped one from the middle point, and Adrian dropped one from the lowest point. The dent in the clay dropped by Cameron was the biggest and the dent in the clay dropped by Adrian was the smallest because the farther things go while falling, the faster they are going when they hit the ground.
We made a chainsaw using the the K’Nex Gears Kit. The boys had a little too much fun with it.
We made a pulley using a metal coat hanger, a spool of thread, two little boxes, and string.
We put coins in one box and demonstrated how the pulley works by moving up and down. Then we put coins in the other box in order to balance the pulley.
We put a pencil under a ruler and then placed pennies at either end. We balanced it perfectly so both ends were off the ground. Then we added a second penny to one end. That side went down while the other side went up. We moved the pencil to make the lever balance once again even though one end had twice the number of pennies as the other end.
With the pencil still under the ruler, we placed a lightweight book on one end of the ruler. We experimented with moving the pencil (fulcrum) to different locations under the ruler (lever) to see where it was easiest to lift the book (load). The answer: Close to the book.
We stacked books and leaned a ruler and a yardstick (inclined planes) against them. We attached a rubberband to a toy card and pulled it up each ramp and also straight up the stack of books. We observed it was the easiest to pull the car up the yardstick, the longest inclined plane, because it had the gentlest slope upward.
We made a screw by wrapping a triangle of paper around a pencil.
We made a phonograph using the the K’Nex Gears Kit.
We hammered a nail into wood. Then we pulled it out and blunted the end. We tried to nail it into the wood again, but it didn’t work as well. This demonstrated why nails, two wedges back to back, make it easier to hammer nails into place.
We put cold water in one bowl, lukewarm water in another bowl, and hot water in a third bowl. We put our hands in the cold and hot water for a little while and then put them in the lukewarm water. The hand that had been in the cold water felt hot while the hand that had been in the hot water felt cold.
We filled a baby food jar as full as possible with beans. We shook the jar to demonstrate how the molecules in a solid vibrate when heated, but do not change shape.
We put a balloon over the end of a baby bottle and placed the bottle in a bowl of very hot water. The balloon filled with air due to the heat making the air expand.
We held a cold jar above boiling water and “caught” the steam in it. The steam immediately condensed back into water inside the jar.
We put identical amounts of water into a small pot and a large pot and put them on the same level of heat at the exact same time. The water in the small pot boiled first. We used a thermometer to measure the temperature of the boiling water. It was right around 212*F for the water in both pots. Then we put cans filled with cold water in each pot of boiling water. The temperature of the water in the can went up, but not quite all the way to boiling.