After playing many parts of the game, and growing excited about how everything worked and interacted... I was curious. "How does gravity work?" I looked into the forums and found a fellow called "Nameless88" and looked over his experiment. Something didn't sit right with me though, and I went to create my own experiments. I went with two versions of Galileo's Gravity experiments in order to figure it out for myself. The results are... Interesting, to say the least, and to me, shows that the gravitational constant of minecraft... Isn't.
All blocks assumed to be 1m x 1m x 1m.
Experiment 1: Freefall
Setup:
Create tower 45 :soil:'s high. Place sand atop soil on side of tower like so:
Stand on sand block.
Process:
Standing on edge of sand block, hit the soil block directly underneath sand block and start timer. Stop timer when sand block hits the ground.
Result:
Average among all trials was 1.8 seconds to fall the height of the tower. The tower, by the above being 45m tall.
Therefore: 45m/1.8s = 25m/s
25m/2 / 1.8s = 13.8888888 m/s^2 = Gravity
Experiment 2: Incline
Setup:
Dig a track which is 45m long and 45m deep, going down and over 1m at a time. Lay track down the length of this slope.
Process:
Stand at top of track. Place cart, stand in cart, start timer. Stop timer at bottom of ramp.
Result:
I assumed the track would be at a 45* Angle:
(-) = Tan-1(45m/45m) = 45*
45^2= 2025
2025+2025 = 4050
sqrt4050 = 63.63961031m for length of track(hypotenuse)
Trial 1: 5.92 s
Trial 2: 5.77 s
Trial 3: 5.86 s
Trial 4: 5.77 s
Trial 5: 6.00 s
--------------------
Trial AVG: 5.876 s
63.63961031m/5.876s = 10.83043062 m/s
10.83043062 m/s / 5.876s = 1.845047805 m/s^2 (Acceleration of the cart)
There are two gravitational constants? There must have been a mistake. Placing a cart on a circular track, I barely nudged it. The cart slowed down, but not quickly enough to make me think friction was playing a large part. The amount of acceleration produced on the cart from a small amount of force reinforced this idea.
Conclusion:
Minecraft does not have a gravitational constant. Gravity acts on objects differently based upon if they are on or are not on an incline. Newtonian Physics do not apply to this world, any further experimentation of the physics in the base game would be incredibly subjective.
Did you really have to do all that just to say minecraft physics aren't good? Lol.
It's a video game, breh. Calm down, like. Go buy some Hollister.
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*puts down cigar
*sips a bit of brandy
Of course my good man , in they year of '86 I was browsing some of the caves in my world looking for a tad bit of coal to keep my abode warm. And what do you know!?!?! a giant combusting scrotum snuck up on me!
I applaud your effort in performing these tests, but I have some bad news for you. Minecraft isn't meant to be realistic and was not designed to match perfectly with real-world physics, it is based on the real world, and will have some common features, but it won't match.
Your experiment had one flaw: you needed to build a replica of the Tower of Pisa first for the first experiment. Then people would have paid more attention! ;D
Your experiments are so flawed that I'm wondering if its an attempt at trolling.
Flaw 1: In experiment 1, your formula for calculating the gravitational constant is wrong. If you fall 45m over 1.8 seconds, then
Distance fallen = 0.5gt² (Do you need a google link for this formula?)
45 = 0.5 * g * 1.8 * 1.8
g = 27.77 m/s²
You took the average speed divided by total time, which does NOT give the gravitational constant.
Flaw 2: You assumed that falling objects accelerate indefinitely. What if there's a terminal velocity (with 0 friction, meaning it accelerates until it hits the speed cap)? What if there's a terminal velocity with friction (meaning it accelerates less over time)?
Flaw 3: In experiment 2, you didn't measure the vertical distance lost by the minecart, you took the traveled diagonal distance and used the same wrong fomula.
Flaw 4: Then you didn't take into account the acceleration rate of a cart vs friction on a slope with the minecart's speed limit of 8m/s per axis (so a minecart has a speed limit of 11.3m/s downslope).
I thought I had a stopwatch somewhere from when I used to use a crosshair eyepiece to time and map sunspots as they passed through the field of view of my solar telescope. Ah, those were the days. But I can't find the stopwatch.
I can measure distance through, and it seemed like a fun science thread, so I did what I like to do, build a big instrument.
70 blocks tall with staggered shelves of glass block so I could stand at the top and throw blocks horizontally and see how far they got while falling a known distance. I had torches to aim at so I knew I was throwing at the horizon. Each was above a shelf 10 blocks lower than the last.
You can see there is an acceleration of gravity just by tossing anything with Q, it goes out then starts to curve down just like anything you toss in the real world. The source of the throw seems to be the camera so I stood on a ledge one block down from the torch sights so I was facing level.
There is a lot of seeming random if you throw a bunch of things without moving. Visually you can see everything isn't on the same arc. So, to account for this, I aimed, then left the mouse alone and tossed a stack of 64 white wool one at a time. Then I went down to see the distance it got, by judging the center of the pile of bobbing wool blocks.
I plotted the points, on this image the height is 1 block per pixel, horizontally it's a tenth of a block per pixel so I could do it in a bitmap grid. You can see a nice arc all the way down as much as 70 blocks. Basically, this graphic would be 700 pixels high instead of 70 to do the true arc travelled.
If it helps with anyone else's math, the distance travelled out for each distance down in this free throw thing:
10 blocks down = 6.0 blocks horizontal
20 = 7.9
30 = 9.1
40 = 9.9
50 = 10.6
60 = 11.2
70 = 11.6
Then...I accidentally burned the whole wool contraption to the ground. What?
Next, I couldn't take falling timings without a stopwatch but I did do the circus stunt fall past a torch tower into a bucket of water:
And at least I can report that the 7 evenly spaced torch gaps went by increasingly fast as I fell just as one would expect. So if it seems to me that the argument being made that there is no gravity acceleration going on predictably, I would disagree. Wish I had a stopwatch though.
Minecraft science. Minecraft scientists battling over what's true and not true. This is as real as Minecraft gets. Minecraft is still a mystery.
Well the bit about putting a minecart on a 45 degree slope and timing it is something anyone who's been in a Physics lab class has done with a weighted "frictionless" incline, but the fact that carts have a capped speed is a good point in why that won't work. You could have a ramp from the sky Y=127 to top of bedrock Y=4 and it's not like it's going to be going at blinding speed. It doesn't have capped energy though so all that potential energy converted to kinetic would keep it going a very very long way.
Well after failing to figure out how to do some sort of redstone timer that would light up torches ever tenth of a second from the time I fall off one pressure plate and land on another (not surprising, I'm a redstone noob so what was I playing at) I decided to do the Tower of Pisa thing. Flying to the top of my circus bucket tower and tossing an object straight forward while releasing fly and personally falling, I reached the bottom just under a second before the object did. So yeah, unlike real life, things don't fall the same speed regardless of mass. Now it may be that a feather falls the same speed as an iron block (goes back to check) yes, appears so, but my body definitely hit the water first.
So maybe gravity but not the same for all masses. Or one calculation for objects and one for your body. I can't think of how to....oh wait. Wolves.
"We will always remember your service to the people, Comrade Laika."
So yeah, one rate of fall for objects, one for bodies (as in, both me and the wolf hit the ground together,) both seem to accelerate.
For the fun of it, I raced both a tossed cube of sand and a placed falling block of sand to the bottom, placed blocks subject to gravity like sand appear to fall at the object rate, not the body rate.
Your experiments are so flawed that I'm wondering if its an attempt at trolling.
Flaw 1: In experiment 1, your formula for calculating the gravitational constant is wrong. If you fall 45m over 1.8 seconds, then
Distance fallen = 0.5gt² (Do you need a google link for this formula?)
45 = 0.5 * g * 1.8 * 1.8
g = 27.77 m/s²
You took the average speed divided by total time, which does NOT give the gravitational constant.
Flaw 2: You assumed that falling objects accelerate indefinitely. What if there's a terminal velocity (with 0 friction, meaning it accelerates until it hits the speed cap)? What if there's a terminal velocity with friction (meaning it accelerates less over time)?
Flaw 3: In experiment 2, you didn't measure the vertical distance lost by the minecart, you took the traveled diagonal distance and used the same wrong fomula.
Flaw 4: Then you didn't take into account the acceleration rate of a cart vs friction on a slope with the minecart's speed limit of 8m/s per axis (so a minecart has a speed limit of 11.3m/s downslope).
Having finished phys 144/146, i can laugh at the math being done wrong in some cases.
But the biggest problem is the units. MineCraft is not meters or feet per (real world) second. Its blocks per second. We cannot yet assume Notch coded the games velocity and accel values to our world units. So what does this mean? We must get a new reading in Blocks per second (velocity) and blocks per second^2 (acceleration).
This way we standardize our measurements so our shared tests have the same internal validity.
This would also mean our expected acceleration of gravity is not 9.81m/s^s, as we are using the block/s^2 (with its own number). Adjust accordingly.
As the OP did his math wrong, any poster who said "its just a game with it own laws" surprises me, they did not see the math before this test. Please read Wikipedia for some background knowledge of dynamics here: http://en.wikipedia.org/wiki/List_of_elementary_physics_formulae
A lack of study on your part does not warrant your vocal ignorance in this tread.
Now how to build a test for the accel in minecraft? That is a challenge, but like one poster had it, we will always mark position over time, and then take the data points into a graph. This can be down for falling sand blocks, entities, carts on tracks, and tossed items. That way we can test for gravity's consistency.
If we can get this data maybe i can build a formula for solve the g constant with my physic book next to me. It would be like my early labs over again!
We will need to be mindful of friction and other hard limits, but these factors will be seen when the g constant is lower than expected or there is no average value within error.
That's right, here at Minecraft science we do everything from scratch, Sky Andrew, we're done here. shut up, couldn't think of a good name...
I wish Notch would add physics, think of a TNT bomb making your burning wood fly everywhere? Think of the possibilitys! Am I the only one that would die for a Red faction like minecraft game? Sure, it isn't very plausible, but it would be cool, I wish Notch would just make, or license a good engine for MC, lwjgl and java won't go on forever.
(Real) Gravity would be weird in minecraft, not only would you have to support buildings, but how would the gravel and sand work? You couldn't create a big tall tower, or it may get knocked down.
Sorry, this post drifts off-topic, I am just a bit overwhelmed with all the math, it hurts my tiny internet brain...
All blocks assumed to be 1m x 1m x 1m.
Experiment 1: Freefall
Setup:
Create tower 45 :soil:'s high. Place sand atop soil on side of tower like so:
Stand on sand block.
Process:
Standing on edge of sand block, hit the soil block directly underneath sand block and start timer. Stop timer when sand block hits the ground.
Result:
Average among all trials was 1.8 seconds to fall the height of the tower. The tower, by the above being 45m tall.
Therefore: 45m/1.8s = 25m/s
25m/2 / 1.8s = 13.8888888 m/s^2 = Gravity
Experiment 2: Incline
Setup:
Dig a track which is 45m long and 45m deep, going down and over 1m at a time. Lay track down the length of this slope.
Process:
Stand at top of track. Place cart, stand in cart, start timer. Stop timer at bottom of ramp.
Result:
I assumed the track would be at a 45* Angle:
(-) = Tan-1(45m/45m) = 45*
45^2= 2025
2025+2025 = 4050
sqrt4050 = 63.63961031m for length of track(hypotenuse)
Trial 1: 5.92 s
Trial 2: 5.77 s
Trial 3: 5.86 s
Trial 4: 5.77 s
Trial 5: 6.00 s
--------------------
Trial AVG: 5.876 s
63.63961031m/5.876s = 10.83043062 m/s
10.83043062 m/s / 5.876s = 1.845047805 m/s^2 (Acceleration of the cart)
Therefore:
(1.845047805 m/s^2)/SIN(45*) = 2.609291629 m/s^s = Gravity
Wait a second...
There are two gravitational constants? There must have been a mistake. Placing a cart on a circular track, I barely nudged it. The cart slowed down, but not quickly enough to make me think friction was playing a large part. The amount of acceleration produced on the cart from a small amount of force reinforced this idea.
Conclusion:
Minecraft does not have a gravitational constant. Gravity acts on objects differently based upon if they are on or are not on an incline. Newtonian Physics do not apply to this world, any further experimentation of the physics in the base game would be incredibly subjective.
It's a video game, breh. Calm down, like. Go buy some Hollister.
But great work regardless :smile.gif:
Flaw 1: In experiment 1, your formula for calculating the gravitational constant is wrong. If you fall 45m over 1.8 seconds, then
Distance fallen = 0.5gt² (Do you need a google link for this formula?)
45 = 0.5 * g * 1.8 * 1.8
g = 27.77 m/s²
You took the average speed divided by total time, which does NOT give the gravitational constant.
Flaw 2: You assumed that falling objects accelerate indefinitely. What if there's a terminal velocity (with 0 friction, meaning it accelerates until it hits the speed cap)? What if there's a terminal velocity with friction (meaning it accelerates less over time)?
Flaw 3: In experiment 2, you didn't measure the vertical distance lost by the minecart, you took the traveled diagonal distance and used the same wrong fomula.
Flaw 4: Then you didn't take into account the acceleration rate of a cart vs friction on a slope with the minecart's speed limit of 8m/s per axis (so a minecart has a speed limit of 11.3m/s downslope).
I can measure distance through, and it seemed like a fun science thread, so I did what I like to do, build a big instrument.
70 blocks tall with staggered shelves of glass block so I could stand at the top and throw blocks horizontally and see how far they got while falling a known distance. I had torches to aim at so I knew I was throwing at the horizon. Each was above a shelf 10 blocks lower than the last.
You can see there is an acceleration of gravity just by tossing anything with Q, it goes out then starts to curve down just like anything you toss in the real world. The source of the throw seems to be the camera so I stood on a ledge one block down from the torch sights so I was facing level.
There is a lot of seeming random if you throw a bunch of things without moving. Visually you can see everything isn't on the same arc. So, to account for this, I aimed, then left the mouse alone and tossed a stack of 64 white wool one at a time. Then I went down to see the distance it got, by judging the center of the pile of bobbing wool blocks.
I plotted the points, on this image the height is 1 block per pixel, horizontally it's a tenth of a block per pixel so I could do it in a bitmap grid. You can see a nice arc all the way down as much as 70 blocks. Basically, this graphic would be 700 pixels high instead of 70 to do the true arc travelled.
If it helps with anyone else's math, the distance travelled out for each distance down in this free throw thing:
10 blocks down = 6.0 blocks horizontal
20 = 7.9
30 = 9.1
40 = 9.9
50 = 10.6
60 = 11.2
70 = 11.6
Then...I accidentally burned the whole wool contraption to the ground. What?
Next, I couldn't take falling timings without a stopwatch but I did do the circus stunt fall past a torch tower into a bucket of water:
And at least I can report that the 7 evenly spaced torch gaps went by increasingly fast as I fell just as one would expect. So if it seems to me that the argument being made that there is no gravity acceleration going on predictably, I would disagree. Wish I had a stopwatch though.
Demographics: Age poll!
Nether poll!
Tamed wolf health as indicated by tail position
Gravity?
Herobrine is Real. #NotIntendedToBeAFactualStatement
Only because it follows unrealistic physics laws that most people don't care about
Well the bit about putting a minecart on a 45 degree slope and timing it is something anyone who's been in a Physics lab class has done with a weighted "frictionless" incline, but the fact that carts have a capped speed is a good point in why that won't work. You could have a ramp from the sky Y=127 to top of bedrock Y=4 and it's not like it's going to be going at blinding speed. It doesn't have capped energy though so all that potential energy converted to kinetic would keep it going a very very long way.
Demographics: Age poll!
Nether poll!
Tamed wolf health as indicated by tail position
Gravity?
Herobrine is Real. #NotIntendedToBeAFactualStatement
If I helped you out, please click the button under my post!
So maybe gravity but not the same for all masses. Or one calculation for objects and one for your body. I can't think of how to....oh wait. Wolves.
"We will always remember your service to the people, Comrade Laika."
So yeah, one rate of fall for objects, one for bodies (as in, both me and the wolf hit the ground together,) both seem to accelerate.
Demographics: Age poll!
Nether poll!
Tamed wolf health as indicated by tail position
Gravity?
Herobrine is Real. #NotIntendedToBeAFactualStatement
Demographics: Age poll!
Nether poll!
Tamed wolf health as indicated by tail position
Gravity?
Herobrine is Real. #NotIntendedToBeAFactualStatement
Taking him seriously?
But the biggest problem is the units. MineCraft is not meters or feet per (real world) second. Its blocks per second. We cannot yet assume Notch coded the games velocity and accel values to our world units. So what does this mean? We must get a new reading in Blocks per second (velocity) and blocks per second^2 (acceleration).
This way we standardize our measurements so our shared tests have the same internal validity.
This would also mean our expected acceleration of gravity is not 9.81m/s^s, as we are using the block/s^2 (with its own number). Adjust accordingly.
As the OP did his math wrong, any poster who said "its just a game with it own laws" surprises me, they did not see the math before this test. Please read Wikipedia for some background knowledge of dynamics here:
http://en.wikipedia.org/wiki/List_of_elementary_physics_formulae
A lack of study on your part does not warrant your vocal ignorance in this tread.
Now how to build a test for the accel in minecraft? That is a challenge, but like one poster had it, we will always mark position over time, and then take the data points into a graph. This can be down for falling sand blocks, entities, carts on tracks, and tossed items. That way we can test for gravity's consistency.
If we can get this data maybe i can build a formula for solve the g constant with my physic book next to me. It would be like my early labs over again!
We will need to be mindful of friction and other hard limits, but these factors will be seen when the g constant is lower than expected or there is no average value within error.
I wish Notch would add physics, think of a TNT bomb making your burning wood fly everywhere? Think of the possibilitys! Am I the only one that would die for a Red faction like minecraft game? Sure, it isn't very plausible, but it would be cool, I wish Notch would just make, or license a good engine for MC, lwjgl and java won't go on forever.
(Real) Gravity would be weird in minecraft, not only would you have to support buildings, but how would the gravel and sand work? You couldn't create a big tall tower, or it may get knocked down.
Sorry, this post drifts off-topic, I am just a bit overwhelmed with all the math, it hurts my tiny internet brain...