Key takeaways
- Slime blocks and honey blocks both stick to adjacent blocks when pushed, but they do not stick to each other – which is the entire basis of flying machines.
- Honey blocks slow you down and stop fall damage; slime blocks bounce you and also stop fall damage.
- Entities standing on a moving honey block are carried with it; entities on a slime block are not.
Slime blocks and honey blocks look like a matched pair – two sticky blocks with opposite colours. They are not. Each has a different set of rules for pushing, for players standing on them, and for entities being carried, and the differences are what every piston contraption more complex than a door is built on.
This guide covers the rules side by side, and the one interaction between them that makes self-propelling machines possible.
Pushing and sticking
Both blocks stick to adjacent blocks when a piston moves them. Push a slime block and everything touching it comes too, up to the twelve-block piston limit.
The rules that bound it:
- Twelve blocks maximum. A piston cannot move more than twelve blocks including the sticky block and everything attached. Over that, nothing moves at all.
- Obsidian, bedrock and block entities do not move. Chests, furnaces and similar either block the push or pop off, depending on the block.
- Slime and honey do not stick to each other. This is the exception that matters.
That last line is the whole trick. Two sticky blocks that refuse to stick to one another means you can build a mechanism where one half pulls away from the other, which is exactly what a self-propelling machine needs – something has to move relative to something else. Every flying machine design uses it.
Our observer and piston circuit guide covers the timing side, which is the other half of any contraption using these.
Standing on them
Here the two diverge completely.
Slime block. You bounce. Fall onto one from height and you are launched back up, with the bounce scaling to the fall. Fall damage is cancelled entirely. Sneaking while landing cancels the bounce, which is how you get off one.
Honey block. You stick and slow down. Movement across the top is reduced, jumping off is harder, and sliding down the side is slow rather than a free fall. Fall damage is reduced but not completely cancelled – unlike slime, which removes it outright.
The side-sliding behaviour is unique to honey. A honey block wall is a controlled descent, which is the only vanilla way to go down a long drop slowly without water.
Both are useful in a build, for opposite reasons. Slime is a launcher; honey is a brake.
Carrying entities
The difference most people never notice, and the one that decides which block a farm design uses.
When a honey block moves, entities standing on top of it move with it. When a slime block moves, they do not – the block slides out from under them.
That makes honey the block for any mechanism that needs to transport a mob or an item without throwing it. Moving platforms, mob transport lines and anything where position matters all use honey for exactly this reason.
Slime’s non-carrying behaviour is also useful – a slime block that slides out from under a mob drops it where you want it, which is a clean release mechanism. Our iron farm guide covers a design where that matters.
Getting the materials
Slime blocks are nine slimeballs. Slimeballs come from slimes, which spawn in slime chunks below Y 40 and in swamps at night. Slime chunks are the reliable source and finding one is a seed-level fact rather than something you can search for. Our swamp guide covers the surface alternative.
Baby slimes can also be obtained from a wandering trader occasionally, and pandas drop slimeballs.
Honey blocks are four honey bottles. Honey bottles come from a beehive or bee nest at honey level 5, using a glass bottle. That is fully renewable and automatable with a bee farm – our bee farm guide covers building one.
The practical difference: honey is renewable on demand, slime is gated behind finding a slime chunk. For a build that needs a lot of sticky blocks, honey is usually the easier supply even where slime would work.
Redstone interactions
Three facts worth having:
- Honey blocks do not stick to slime blocks, as above – the foundation of flying machines.
- Neither conducts redstone. A redstone signal will not pass through either, which makes them useful as insulators in a cramped circuit. Our redstone basics guide covers what does conduct.
- Honey blocks prevent you from jumping while on them, which can be used as a soft barrier that does not block line of sight the way a solid block does.
For an automatic door or a hidden mechanism, the insulating property is the one you will reach for most. Our automatic door guide covers a build where keeping signals separate in a small space is the main constraint.
Which to use
A short decision list.
- Need to move blocks as a group? Either. Pick by what else the block has to do.
- Need to carry entities on a moving platform? Honey. Slime will drop them.
- Need to launch a player or a mob? Slime.
- Need a controlled descent? Honey, down a wall.
- Need to cancel fall damage completely? Slime. Honey only reduces it.
- Building a flying machine? Both, because the whole design depends on them not sticking to each other.
- Just need a renewable sticky block? Honey, because bees are easier than slime chunks.
The pair is one of the better-designed things in Minecraft – two blocks that look interchangeable, behave differently in four separate ways, and whose single shared exception unlocks a whole category of machine. Our Create mod guide covers what happens when a mod builds on top of that idea.
Images: Vanilla Experience+ project gallery.