Recording sensor readings in a spreadsheet with timestamps
Name:
Date:
Class:
A
Quick Questions
Shade in the A or B circle for each question.
1. How should a sensor log store each new reading?
2. Which column should come first in a sensor log?
3. Which header is better for a temperature column?
4. A logger records temperature and humidity every minute. How many measurement columns does the log need?
5. Which is the better way to record a reading in the Temp (C) column?
B
Match the Pairs
Draw a line connecting each item on the left to its match on the right.
| Left column | Right column | |
|---|---|---|
| 1Timestamp,Temp (C),Humidity (%) | ATemp (C) | 22.4 | |
| 22026-03-02 09:15,22.4,58 | BThere is no timestamp column, so you cannot tell when each reading was taken, and the headers have no units. | |
| 3Each new sensor reading is added as its own row, so the log grows downwards | C2026-03-02 09:15,22.4 2026-03-02 09:30,22.9 2026-03-02 09:45,23.1 | |
| 4Putting the unit in the header means each cell holds only a number, which can be used in calculations | DA header row: a timestamp column first, then one column per measurement, with units in brackets | |
| 5Temp,Humidity,Light 22.4,58,640 | EThe row has three values but the header has only two columns, so a measurement has no column or label. | |
| 6Timestamp,Temp (C) 2026-03-02 09:15,22.4,58 | FOne reading stored as a single row: the date and time, then the temperature and humidity measured at that moment |
C
Definitions
one row per reading
D
Fill in the Blanks
Complete each line of code by filling in the missing parts.
1.
Timestamp,Temp (_),Humidity (%)
2.
_________,Temp (C),Light (lux)
3.
=___(A2:A50)
4.
=______(A2:A50)
5.
Timestamp,Temp (C),Humidity (_)
E
Spot the Error
Shade in the letter of the line that contains an error.
Question 1
A
Time,Temp (C),Humidity (%)
B
2025-03-01 09:00,21.5
C
2025-03-01 09:10,21.8,47
D
2025-03-01 09:20,22.1,46
Question 2
A
Time,Light (lux)
B
2025-03-02 08:00,310 lux
C
2025-03-02 08:05,325
Question 3
A
Time,Temp (C)
B
10:00,18.2
C
09:05,18.4
D
10:10,18.7
Question 4
A
Time,Temp (C),Moisture (%)
B
2025-04-01 07:00,15.2,40
C
2025-04-01 07:30,15.9,39
D
2025-04-01 08:00,16.4,high
Question 5
A
Time,Temp,Humidity
B
2025-03-01 09:00,21.5,48
C
2025-03-01 09:10,21.8,47
Answer Key
Recording sensor readings in a spreadsheet with timestamps
Section A: Quick Questions
Q1
B — As its own new row
Q2
B — Timestamp (date and time)
Q3
A — Temp (C)
Q4
A — Two: one for temperature and one for humidity
Q5
A — 21.5
Section B: Match the Pairs
Q1
Timestamp,Temp (C),Humidity (%) → A header row: a timestamp column first, then one column per measurement, with units in brackets
Q2
2026-03-02 09:15,22.4,58 → One reading stored as a single row: the date and time, then the temperature and humidity measured at that moment
Q3
Each new sensor reading is added as its own row, so the log grows downwards → 2026-03-02 09:15,22.4
2026-03-02 09:30,22.9
2026-03-02 09:45,23.1
Q4
Putting the unit in the header means each cell holds only a number, which can be used in calculations → Temp (C) | 22.4
Q5
Temp,Humidity,Light
22.4,58,640 → There is no timestamp column, so you cannot tell when each reading was taken, and the headers have no units.
Q6
Timestamp,Temp (C)
2026-03-02 09:15,22.4,58 → The row has three values but the header has only two columns, so a measurement has no column or label.
Section C: Definitions
Q1
one row per reading — A sensor log stores each reading as its own row: a timestamp column for the date and time, then one column per measurement, with units in the header, such as Temp (C).Section D: Fill in the Blanks
Q1
Timestamp,Temp (C),Humidity (%)Q2
Timestamp,Temp (C),Light (lux)Q3
=MAX(A2:A50)Q4
=COUNTA(A2:A50)Q5
Timestamp,Temp (C),Humidity (%)Section E: Spot the Error
Q1
B — This reading row is missing its humidity value, so it has fewer columns than the header. Each row needs a value for every column: 2025-03-01 09:00,21.5,48.
Q2
B — The unit is written inside the data cell, which turns the number into text. Units belong in the header, Light (lux), so the cell holds only 310.
Q3
C — The timestamp is out of order. Readings are logged in time order, so after 10:00 the next row should be 10:05, not 09:05.
Q4
D — The Moisture (%) column should hold numbers only. The word 'high' is text and can't be averaged or charted. It should be the number 38.
Q5
A — The header is missing the units. Each measurement column should show its unit, e.g. Temp (C) and Humidity (%), so the numbers have a clear meaning.