No one can tell you why gravity is… that’s just the way the universe is wired. Gravitation is a natural thing that happens when you have mass.  Galileo was actually one of the first people to do science experiment on gravity.


Galileo soon figured out that objects could be the same shape and different weights (think of a golf ball and a ping pong ball), and they will still fall the same. It was only how they interacted with the air that caused the fall rate to change. By studying ramps (and not just dropping things), he could measure how long things took to drop using not a stopwatch but a water clock (imagine having a sink that regularly dripped once per second). Let’s learn more about gravity right now:


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18 Responses to “Unit 1: Mechanics (Gravity) Video”

  1. Crazy as this experiment sounds, it’s legit! My team has done similar experiments with a “rocket ship” suspended on a string. The corona effect from high voltage leaking from a sharp edge has a decent amount of force. I believe there was a proposal for a deep space propulsion system back in the 60’s… HOWEVER…the warnings about danger are not fake – it IS very dangerous to play with an old TV – the capacitors inside an old TV holds charge for months, and can blast you across the room with its shock. Kids should never take apart old TVs but rather leave them in the dumpster.

    That said, I did make a safe version of this device and it’s in my summer e-Camp program in the Electricity Lab. There is also a homemade device that does the same thing – levitate foil objects – but it’s totally safe and easy to do. You can get one from this website:
    http://unitechtoys.com/funflystick.html

    If you really want to do more research, here are a couple more websites you can read up on:

    This one is cool with lots of engine ideas
    http://www.waynesthisandthat.com/ep2.htm

    Here’s a NASA project
    http://www.nasa.gov/centers/glenn/about/fs21grc.html

    Hope this helps!
    Aurora

  2. Charese Baker says:

    Hi Aurora, We  really enjoy a night time drama called Num3ers.   One of the characters who is a math genius along with his colleague, made something called an electrostatic propulsion lifter.   My son’s eye’s light up and of course he thinks it was very, very cool.  I researched it and know it very, very, very dangerous.   Here’s a quote & info I found from a website.  “Safety Lifters are not Toys.  A Lifter is an extremely dangerous High-Voltage electrostatic propulsion device. It IS VERY DANGEROUS!  Firstly, make sure that no one can come in contact with it – mainly onlookers, and yourself. Keeping large distances between the potential victims from any possible contact with the high voltage is really the only foolproof way of protecting against electrocution. People not familiar with high voltage  can be very naive. Always keep a safe distance from your lifter.” The website went on and used the words high voltages,  extremely dangerous, electrocution, death, etc.  All words that made me say…..Uh no, we will NOT be making this.  My diamond in the rough, surprisingly agreed.  I guess it was the number of times I kept stressing the words death, voltage, electrocution,  but I digress.  So, [you probably] knew this was coming, 1) Will or has Supercharged Science ever made one of these?  2) Is there a way to make one which doesn’t end with  in all the descriptive words  that made me run and hide under the covers.  I must admit it did look very cool, and oddly simple, on TV.  The tools seemed simple, balsa wood stick, aluminum foil, etc.   The science behind it seems very, very complex.   We await your wisdom! with admiration and respect, Rese

  3. They sure are! Think about Mars – it’s a giant rock, and so because it has mass, it has a gravitational field. You’d stick to the surface like you do on the Earth. But the inner core has cooled off, so its magnetic field is mostly gone, which is why the sun has blasted away most of the atmosphere.

    A magnet interacts with other magnets some metals through a magnetic field – when you toss a magnet at the fridge, it sticks, right? That’s because the magnet can play in two fields at the same time: gravitational (when it falls) and magnetic (when it sticks). The magnet starts to fall, but sticks to the fridge before it hits the ground.

    What happens if you toss a small rock at the fridge? Does it stick?

    Nope! Which means that the rock doesn’t interact in a magnetic field but it does in a gravitational field (it hits the ground).

    The Earth provides us with the gravitational field and a weak magnetic field (weak compared with the magnet, but only because we’re closer to the magnet that the core of the Earth.)

    Does that help?

  4. Nazliatul Aniza Nordin says:

    Hi. The earth’s gravity and the earth’s magnetic field- are they totally different things? Thanks!

  5. Suna Price says:

    This is really great stuff! This experiment was so simple but taught so much! We are enjoying the process of recording our experiments in the science journal as well, it gets us to be more focused and involved with the scientific method.

  6. Good question! Newton’s laws of motion is all about how objects move (or don’t move), so we talk about things like forces and acceleration. The first unit is all about the different kinds of force you might encounter (like from friction, or due to gravity…). The second unit is all about the motion part and covers velocity and acceleration. Does that help?

  7. Nazliatul Aniza Nordin says:

    Hi Aurora!
    How does Newton’s Law Of Motion relate to Unit 1: Mechanics?
    -Dayini (12) 🙂

  8. jack redberger says:

    Hi,
    where is the video about astronauts trying that experiment in space?

    Thanks

  9. Great question! You’ll learn more about this in Unit 7, Lesson 2, but for now…the reason why the planets orbit the sun is because the Sun’s gravity keeps them in their orbits. If they stayed in one spot, they would fall right into the sun because the sun is so much larger than the planets (and thus has more gravitational attraction). Think of how the Moon goes around the Earth – the pull of Earth’s gravity keeps the moon going in an orbit around the Earth. Does that help?

  10. For an 80 pound weight, you’d weigh:

    30 pounds on Mercury
    72 pounds on Venus
    13 pounds on the Moon
    30 pounds on Mars
    189 pounds on Jupiter
    85 pounds on Saturn
    71 pounds on Uranus
    90 pounds on Neptune
    5.3 pounds on Pluto

  11. Teresa Pipkins says:

    and why do the planets orbit around the sun? why dont they just stay in one place?

  12. Teresa Pipkins says:

    how much would i weigh on mars? (i weigh about 80 pounds)

  13. Michele Floyd says:

    wendy fobes try to restart your computer if it freezes again

    =)

  14. Hmmm… sorry about the delayed response – I just found your comment in the spam folder. Okay, which videos are you having trouble with?

    Aurora

  15. Theron Rose says:

    I am having a problem with the audio on some of the videos. I’ve tried both IE and FireFox
    No difference. Unable to hear. Thank you

  16. Try the videos again – do they work for you now?

  17. Wendy Fobes says:

    Hi – is anyone else having problems with the videos? I didn’t have any trouble with the summer sessions, but I haven’t been able to get the videos to work in the Gravity section ( I got about 45 seconds of A Weighty Issue then it froze)