Forces of Nature Archive

  • Water Pressure and Depth

    Water Pressure and Depth

    Have you ever watched scuba divers on tv? They face many challenges when they dive. The deeper that a scuba diver descends, the more dangerous the dive becomes. During a dive, divers can experience lots of different problems. Some of these problems can be lightheadedness, joint pain, coordination loss, and even paralysis. Why?
    The answer to that question has to do with air, gas, and even pressure.
    Did you know that water pressure is much more dense than air pressure?
    In this experiment, you’re going to observe how pressure changes with depth.

    What You’ll Need:

    Sharpie (marker)
    Duct tape
    1 clear 2-liter bottle with lid
    3 in. nail with a sharp point
    An adult to help


    1. With the scissors; remove the label from the bottle so that you can observe what happens within the bottle.
    2. Using the ruler and marker; make a mark on the bottle that’s 3 inches from the bottom of the bottle.
    3. Make another mark that is 8 inches from the bottom of the bottle. Do this directly above the first mark that you made.
    4. With the cap still on the bottle, lay the bottle down on a flat surface. Your bottle should now be horizontal.
    5. Have an adult use the sharp nail to poke a hole into the two marks that you made on the bottle.
    6. Using your duct tape, put a small piece of tape over the holes that were made to cover them.
    7. Fill the bottle, clear to the top, with water.
    8. You can either set the bottle at the side of the sink with the holes facing toward the sink or you can take it outside for this next part.
    9. Quickly remove the tape from both holes and watch what happens!
    10. What is your observation?

    When the tape is removed, water will shoot out of both of the holes. The bottom hole has the water exiting the bottle more forcefully. Why?
    The bottom hole is deeper under the water and therefore under greater pressure. There is more weight pressing down on the bottom so it makes the water exit with more force.

    A Step Further:

    For a full experiment and project, make other holes at different depths in the bottle. Test to see if the water pressure increases at a steady rate the closer the holes are to the bottom. Try using a wider container. Discover whether or not more water matters or if depth is what matters most.
    You can also use salt water vs. regular water. Salt water weighs more than regular water.

  • Collect Micrometeorites

    Micro Meteorites In The Making




    Every single day countless numbers of meteorites have been falling to the Earth. Why haven’t you seen them laying around? You don’t usually notice them because, by the time they land, they’re about the size of small pebbles.

    This is more of a collection than an experiment, although you can certainly use meteorites in an experiment due to the difference in their properties.


    Here’s What You’ll Need:

    • Flat open space – You’ll want to find an open area such as a field to try and locate your meteorites. This is a space with no trees in the way. If you live in the city, go to a park that has few trees and no large buildings around it.
    • A large piece of white paper
    • A magnifying glass
    • A magnet


    What To Do:

    Choose a day that is dry. This means a day that has little to no chance of precipitation. You don’t want it to be windy either. So choose a day that is both calm and dry.

    Put your paper on the ground in an area where it won’t be disturbed. Make sure that there is clear open sky above.

    Leave the paper for about 6 to 8 hours. The longer that you leave the paper lying there, the better your chances of collecting meteorites. It’s not a bad idea to weight the paper down, just in case of a random gust of wind or breeze. Placing a large rock in the center is the best option as anything that hits your paper will slide down toward the middle where the rock is located.

    When the time comes to collect your paper, do so gently and fold the paper up at the edges so that any captured material stays in the center and doesn’t fall out.

    Now, use the magnet and run it along the underside of your white paper. You might need to run it back and forth a few times so that it picks up as many metallic particles as it can.

    With the magnet still firmly up against the paper, tip the paper gently to let the dust and dirt slide off and allowing the metal particles to stay attached to the magnet.

    Dark particles with pitted surfaces are likely what you’re going to be left with. If they’re super small, try placing them under a microscope to get a great look at what you’ve collected. Chances are great that you’ve collected micrometeorites!

    There isn’t too much out there that discusses micrometeorites in a way most of us can understand, but here are three that look interesting …