How heavy is that really?
Max's head is a light bulb, and it may weigh 60 grams and not one gram more. That is 12 nickels. Here is why a number that small can stop a whole robot.
- How long
- About fifteen minutes.
- You need
- 12 nickels · An empty paper towel tube · Tape
- Messy
- No.
Step 1. Count 12 nickels into your hand.
A nickel weighs exactly 5 grams. That is not a guess: the Mint makes every one to that weight. So 12 of them weigh 60 grams, which is the most Max's bulb is allowed to weigh.
No nickels? Pennies from 1983 on weigh 2.5 grams each, so it takes 24. Check the date. Older pennies are heavier, which is a good reason to always check.
Step 2. Find where it sits on the ladder.
The ladder below is in grams. The orange bars are ours, off Max's own drawings. The dark dashed line is the ceiling. A golf ball fits under it and so does an egg, just. Look at what is sitting right beside it.
Step 3. Tape the nickels to the top of the tube.
Stack them, tape them on top of the tube, and stand it on the table. Push the top very gently sideways with one finger, a little more each time, until it tips over. Notice how little it took.
Step 4. Now tape them to the bottom and push again.
Same nickels, same tube, same push. Tape them round the bottom edge instead. It leans further before it goes, or it rocks and stands back up. Nothing got lighter. The weight only moved.
Step 5. Read why Max is stuck.
Max is about 315 millimeters tall and his bulb sits right on top, the way your nickels did. Read the card below the ladder.
The ladder, in grams.
- A dollar bill1 g
US Bureau of Engraving and Printing, about 1 g
- A nickel5 g
US Mint specification, 5.000 g
- One of Max's steel foot plates31 g
Max tech pack, MAX-401, about 31 g
- A golf ball, the heaviest allowed45.9 g
Rules of Golf, no more than 45.93 g
- A large egg56.7 g
USDA size Large, 24 oz a dozen, so 56.7 g each
- Max's bulb, the most it may weigh60 g
Max tech pack, MAX-302, no more than 60 g
- Both of Max's foot plates together62 g
Max tech pack, MAX-401, two at about 31 g
Light dashes every 10 g. The dark dash is the 60 g ceiling.
Why sixty grams
The heavy part of Max is on top of him.
That is the tube with the nickels on top. So he gets the tube with the nickels on the bottom too: a steel plate hidden under each foot, about 31 grams each. Look at the ladder again. All the steel in his feet weighs about the same as the most his head is allowed to.
The rule on the drawing is that he has to stand up when he is tilted 8 degrees in any direction, and 15 degrees on his wooden stand, which has magnets that grab the steel in his feet. A heavier bulb raises his center of gravity and he fails that test.
Why he is stuck
Three rules at the same time.
- 1It has to run on 5 volts, the same as a phone charger, so it is safe to hand to anybody.
- 2It has to look like an old bulb with a glowing wire inside, because that is his face.
- 3It has to weigh 60 grams or less, or he falls over.
Any one of those is easy to find. All three in one bulb is the part nobody has found yet, which is why no wood has been cut on him. We have not weighed a real one, so there is no bar for it on the ladder. When there is, it goes on.
That is the end of this one
The word for what you just did is center of gravity.
The center of gravity is the one spot where all of a thing's weight acts as if it were sitting there. Put weight up high and that spot climbs, and a tall thing tips over with a smaller push. Put weight down low and it stands up to a bigger one. Every lamp, every ladder and every person standing on one foot is working this out.
Where to go now