Level sensor

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Quick Questions

Shade in the A or B circle for each question.

1. What does a level sensor measure?

A The height of a liquid or solid in a container

B The temperature of the liquid in a container

2. Which use suits a level sensor better?

A Checking how much water is in a water tank

B Checking how bright a room is

3. A car's fuel gauge uses a level sensor. What data does it capture?

A How high the fuel is in the tank

B How fast the fuel flows through the engine

4. True or false: a level sensor can only be used with liquids.

A True - it can only measure liquids

B False - it can also measure solids such as grain or powder

5. A chemical vat must never overflow. Which sensor helps to prevent this?

A Humidity sensor

B Level sensor

Match the Pairs

Draw a line connecting each item on the left to its match on the right.

Left column		Right column
1level sensor		Adata captured = height of contents
2fuel gauge		BIF level >= vatFullHeight THEN stop filling
3A level sensor captures the height of the contents of a container, such as the water in a tank		CA level sensor can detect the height of both liquids and solids. Water tanks, fuel tanks and chemical vats are all common liquid uses.
4A level sensor can monitor how full a chemical vat is so that the vat is not overfilled		DA use of a level sensor that tells the driver how much fuel is left in the tank
5A level sensor measures the temperature of the liquid in a tank		EA level sensor does not measure temperature. It measures the height of the contents, which shows how full the container is. A temperature sensor measures temperature.
6A level sensor is only used for solids, never for liquids in a water tank		FA sensor that measures how full a container is by detecting the height of a liquid or solid

Definitions

level sensor

Fill in the Blanks

Complete each line of code by filling in the missing parts.

height ← ____(LevelSensor)

tank ← READ(___________)

level ← READ(LevelSensor) IF level _ 20 THEN OUTPUT "Fuel low"

IF level >= 90 THEN OUTPUT "Tank full" _____

_____ ← READ(LevelSensor) OUTPUT level

Spot the Error

Shade in the letter of the line that contains an error.

Question 1

A level ← GET_LEVEL()

B IF level < 20 THEN

C OUTPUT "Stop the pump"

D ENDIF

Question 2

A fuel ← GET_LEVEL()

B IF fuel <= 10

C OUTPUT "Low fuel warning"

D ENDIF

Question 3

A tank ← GET_LEVEL()

B WHILE tank > 100

C OUTPUT "Filling"

D tank ← GET_LEVEL()

E ENDWHILE

Question 4

A vat ← GET_LEVEL()

B IF vat <= 90 THEN

C valve ← CLOSED

D ENDIF

Question 5

A level ← GET_LEVEL()

B percent ← level / 200 * 100

C OUTPUT percent & % full

Answer Key

Level sensor

Section A: Quick Questions

A — The height of a liquid or solid in a container

A — Checking how much water is in a water tank

A — How high the fuel is in the tank

B — False - it can also measure solids such as grain or powder

B — Level sensor

Section B: Match the Pairs

level sensor → A sensor that measures how full a container is by detecting the height of a liquid or solid

fuel gauge → A use of a level sensor that tells the driver how much fuel is left in the tank

A level sensor captures the height of the contents of a container, such as the water in a tank → data captured = height of contents

A level sensor can monitor how full a chemical vat is so that the vat is not overfilled → IF level >= vatFullHeight THEN stop filling

A level sensor measures the temperature of the liquid in a tank → A level sensor does not measure temperature. It measures the height of the contents, which shows how full the container is. A temperature sensor measures temperature.

A level sensor is only used for solids, never for liquids in a water tank → A level sensor can detect the height of both liquids and solids. Water tanks, fuel tanks and chemical vats are all common liquid uses.

Section C: Definitions

level sensor — A sensor that measures how full a container is by detecting the height of a liquid or solid, e.g. in a water tank, fuel gauge or chemical vat.

Section D: Fill in the Blanks

height ← READ(LevelSensor)

tank ← READ(LevelSensor)

level ← READ(LevelSensor)
IF level < 20 THEN
  OUTPUT "Fuel low"

IF level >= 90 THEN
  OUTPUT "Tank full"
ENDIF

level ← READ(LevelSensor)
OUTPUT level

Section E: Spot the Error

C — A low level means the water tank is nearly empty, so the pump should be started, not stopped. The line should be OUTPUT "Start the pump".

B — An IF statement must end with THEN. The line should be IF fuel <= 10 THEN.

B — The tank should keep filling while the level is below full. With > 100 the loop would not run when the tank is not yet full. It should be WHILE tank < 100.

B — The inlet valve must close when the chemical vat is nearly full, which means a high level. It should be IF vat >= 90 THEN.

C — The text "% full" is a string, so it must be in quotation marks. It should be OUTPUT percent & "% full".