Mirror & Water Images
🔒 Log in to trackWater images (horizontal mirror)
🔒 Log in to trackA water surface acts as a horizontal mirror below the object: it swaps top and bottom and keeps left and right. So in a water image:
- the order of characters stays the same, and
- each character is turned upside down (flipped top-to-bottom, not rotated).
Letters with a horizontal axis of symmetry — B C D E H I K O X (and digits 0, 3, 8) — look unchanged in water. A word made only of these letters (CHOICE, CODE, HIDE, BOX) looks identical in water.
A mirror image followed by a water image is the same as a half-turn (180° rotation).
Detailed notes
What water does
A lake below a hill shows the hill upside down. The water surface is a horizontal mirror below the object. It swaps top and bottom and keeps left and right. A question may also say "the mirror is placed horizontally below" or "along the line MN below the figure". All of these mean a water image.
For a word, number or code:
- The order stays the same: the first character is still first.
- Each character is turned upside down (flipped top to bottom, not spun round).
Symmetric letters and digits
Capitals with a horizontal line of symmetry look the same in water: B C D E H I K O X (and the digits 0, 3 and 8).
- A word looks exactly the same in water if every letter is in this list. The order does not matter here because water keeps the order. Examples: CHOICE, BOX, HIDE, CODE, DECIDE.
- Letters such as A, M, T, U, V, W, Y are symmetric in a mirror but not in water. M upside down looks like W.
Four-step check for option questions
- First character stays first. An option starting with the last character is a mirror image or a 180° turn.
- Check one letter that is not in the list (A, R, T, 4, 7). It must be upside down.
- Left-facing parts must still face left. For example, the bowl of R stays on the right side.
- Compare the rest only if two options are still left.
Mirror + water = half turn
A mirror image followed by a water image (in either order) is the same as turning the object through 180°. The order is reversed and every character is upside down. The letters H, I, N, O, S, X, Z and the digits 0 and 8 look the same after a half turn. So SOS, NOON and XOX look unchanged after a half turn.
Figures
Every point moves to the same distance on the other side of the horizontal line. Things at the top go to the bottom; left and right do not change.
- A feature in the top-left goes to the bottom-left.
- Top-right is the mirror image (wrong axis); bottom-right is a 180° turn.
Worked example
Water image of BUDGET. The order stays B U D G E T. B, D and E are symmetric in water and look unchanged. U, G and T appear upside down (T looks like ⊥). An option that begins with T is not a water image.
Quick revision
- Water: order kept + each character upside down; left stays left.
- Symmetric in water: B C D E H I K O X; digits 0, 3, 8.
- Same word in water = every letter in that list (no palindrome needed).
- Mirror + water = 180° turn: reversed order + upside down.
- Figures: top ↔ bottom, left and right unchanged.
Types of questions asked
Every way this subtopic shows up in exams — how to recognise it, the formula or logic to use, and a solved example.
Type 1: Water image of a wordvery common3 practice Q
A word in capitals; mirror placed horizontally below it.
- Keep the order.
- Turn each letter upside down; B C D E H I K O X look unchanged.
- Left-right direction of each letter stays.
Why: a horizontal mirror only swaps top and bottom.
Example: Which describes the water image of BUDGET?
Order B U D G E T; U, G, T upside down; B, D, E look unchanged.
Type 2: Water image of a number or codecommon2 practice Q
A number or letter-digit code with water image options.
- Keep the order.
- Turn each character upside down; 0, 3, 8 look unchanged.
- 6 upside down is not 9 (9 is a half turn of 6).
Why: water is a flip, not a rotation.
Example: Which digits of 83602 look unchanged in water?
8, 3 and 0. 6 and 2 appear upside down.
Type 3: Water image of a figurevery common3 practice Q
A line figure with a horizontal line MN below it.
- Pick a clear feature.
- Move it to the other side of the horizontal line; keep its left-right position.
- Reject options where it moved sideways.
Why: water keeps left and right.
Example: A figure has a shaded triangle in its top-right corner. Where is it in the water image?
Bottom-right corner.
Type 4: Letters or words unchanged in watercommon2 practice Q
How many letters look the same in water, or which word looks the same.
- Tick letters from B C D E H I K O X.
- For a whole word, every letter must be ticked.
Why: these letters have a horizontal line of symmetry.
Example: Which word looks the same in water: CHOICE or CHANCE?
CHOICE: every letter is in B C D E H I K O X. CHANCE has A and N.
Type 5: Mirror image followed by water imageoccasional3 practice Q
The mirror image of a word is seen again in water (or the reverse).
- Mirror then water = a 180° turn.
- Reverse the order and turn every character upside down.
Why: swapping left-right and then top-bottom is a half turn.
Example: How does the word SUN look after a mirror image followed by a water image?
Turned through 180°: N U S order, each letter upside down. N and S look the same, U looks like ∩.
Shortcut tricks
⚡ Order stays, letters go upside down
Scan the options for the one that keeps the original order and has only asymmetric letters turned upside down.
Example: Q. Water image of BOX?
Sol. B, O, X are all top-bottom symmetric, and water keeps the order → BOX looks unchanged.
Water image: same order, top-bottom flip.
Where students lose marks
Reversing the character order in a water image.
Rotating letters by 180° instead of flipping them top-to-bottom.
Practice sets — 18 questions
Sets of 10, mixed across the question types above. Each answer comes with a step-by-step explanation.
Topic test · 10 questions
Suggested time 7 min · wrong answers go to your mistake notebook automatically.