Thermometers

What is Thermometers?

Thermometers is a logic puzzle played on a grid covered by thermometers. Each one runs along a row or down a column for one cell or more, with a round bulb at one end, and you fill cells with mercury. A thermometer always fills from its bulb, with no gaps: it can stay empty, fill part of the way, or fill right to its tip. The numbers along the top and the left of the board say how many cells of each column and each row hold mercury.

Every board has exactly one answer, and it can always be reached by reasoning, never by guessing. Boards come in three sizes, 6 by 6, 8 by 8 and 10 by 10, and a new board, the same for everyone, arrives every day.

How to play

Tap a cell to pour mercury into its thermometer up to that cell.

• Filling. A tap on an empty cell fills its thermometer from the bulb up to it, straight through any crosses on the way.
• Emptying. A tap on a full cell empties it: the cell gets a cross, and the mercury drops to just below it.
• Crosses. A cross is only your note that a cell stays dry. Tap a cross to clear it, drag across cells to cross out several at once, and once a row or column holds all its mercury, tap its number to cross out the rest of it.
• Numbers. A number dims when its line holds exactly that much mercury, and turns red when the line holds more, or can no longer reach it.
• Undo. Undo takes back your last change, a whole drag at a time.
• Score. Your score is the time to fill the board, plus 30 seconds for every hint. Every board size has its own leaderboard.

Strategy tips

1. Start with the extremes. A 0 keeps its whole line dry, and a number as big as its line fills every cell of it. Each of those settles cells in the lines that cross it too.
2. Mercury reaches back to the bulb. Once a cell holds mercury, every cell between it and its bulb holds mercury as well; once a cell is dry, every cell past it is dry.
3. A long thermometer in a short line. A thermometer lying along a row can only fill as far as the row's number allows, so the cells past that point stay dry.
4. The rest of the line is not enough. If the other cells of a row cannot make its number on their own, a thermometer lying along it must fill at least the difference, starting from its bulb.
5. Read two lines together. On the large boards, a thermometer running down through two neighbouring rows fills both of them at once. Weighing the two rows together often settles a cell that neither row settles alone.

FAQ

Is Thermometers free to play?

Yes. Like every game on Play, it runs free in your browser, with no download and no account needed.

Does every thermometer have to hold some mercury?

No. A thermometer can stay completely empty, fill part of the way from its bulb, or fill to the top. It can never have a gap.

What does a hint do?

It fixes a wrong mark first if there is one; otherwise it fills what the next step of logic finds from the marks on the board, crosses out the cells that step knows stay dry, and the line under the board says which rule it used. Each hint adds 30 seconds to your time.

What are today's thermometers?

Every day everyone plays the same medium 8 by 8 board, so times compare directly on the leaderboard.

How is my score counted?

Your score is the time from the first look at the board to the last drop of mercury, plus 30 seconds for every hint. Lower is better.