Do you have kids that like to know how things work? Now is the time to introduce them to science, the study of matter, energy, space, and time. If hearing the word science’ gives you a knot in your stomach, be brave and read on. Science is all around us. It is in the food we eat, the cars we drive and the plasma TV we use to watch football games. It’s even behind the forces that keep that football in the air all the way through the goal posts, or maybe not.
Doing these simple experiments with your kids will not only introduce them to scientific principles but also how interesting and fun science can be.
Surface tension is the result of the molecules of water sticking together on the surface to form an elastic like film. Surface tension is the reason that small bugs like the water strider (pond skater, UK) can walk on water without sinking.
Take a glass of water filled almost to the rim. Put a cork into the water and watch it float. Eventually, it will float to the side of the glass. Can you make the cork go back to the middle and stay there?
Here’s how to make the cork stay in the middle. Add water to the glass one spoonful at a time. When the water level rises high enough the cork moves to the center.
Why? The surface tension of the water causes it to rise above the glass where it will form a small curved dome with the highest point at the center. The cork seeks the highest point of water.
Arrange wooden toothpicks in a circle in a shallow bowl of water. Place a cube of sugar into the center of the toothpicks. Watch how the toothpicks are drawn to the center of the bowl.
Change the water in the bowl and put the toothpicks in a circle again. This time, put a bar of soap in the center of the toothpicks. This time, the toothpicks scatter.
Why? As the sugar sucks up water, it creates a current that carries the toothpicks toward the sugar. The soap, on the other hand, gives off an oily film that spreads outward. It weakens the surface tension and carries the toothpicks away with it.
TUNING A GLASS
Line up eight drinking glasses in a row, all the same size if you have them. Fill the glasses with different amounts of water. The glass with the most water is on the far left. Each glass to the right has a little less water. The glass on the right end has the least amount of water.
Now use the pencil to strike the side of each glass. You will hear a different tone from each of the glasses.
Why? Sound is caused by vibration. The speed of the vibration depends on the amount of water in the glass. The more water there is in the glass, the slower the vibration and the deeper the tone.
Call the first glass on your left “do”, which is the first note on the musical scale. Strike the next glass. If its tone is the next on the musical scale, continue on with the rest of the glasses. If any glasses need adjustment to hit the note on the scale, add water or pour some out. When you have finished tuning each glass, you can play the musical scale.
An experiment performed in 1851 by French physicist Jean Bernard Leon Foucault demonstrated that the earth rotates. He suspended a 200 foot (61 m) pendulum from the Pantheon, a huge public building in Paris. You can make a smaller version of the pendulum to trace the same path.
Push a knitting needle through the center of a ball and attach the end of the knitting needle to a piece of string or wire. Tape the pendulum to the ceiling so it can swing freely. Next, tape a piece of paper to the floor and mark a line directly under the knitting needle. Start the pendulum swinging directly along the line and watch what happens after two hours.
What happened? Although the pendulum is still swinging on its original path, it is no longer swinging over the line you made. Inertia keeps the pendulum swinging in the same place, but the earth has moved. It moved because of the earth’s rotation.
MAKE A RAIN GAUGE
You can measure the amount of rain that falls at your house or school and compare the results with the official statistics.
Collect various empty containers that are clear and have parallel sides. Use a ruler mark off inches or centimeters on a strip of masking tape. Attach the tape to the various containers. Place the containers on a flat, level surface outside.
Each time it rains, measure the amount of rain in the containers. The levels should be the same whatever the size of the container, provided that its sides are parallel. Record the amount and date.
Compare the measurements from one rainfall to the next. Compare your measurements with those announced on television or radio. They may not always agree. Sometimes the amount of rain is different from one side of the street to the other.
Once kids see how much fun they can have with sciences “tricks,” they will be eager to show their friends and continue learning about the many amazing fields of science.