🔢 MathGrade 2Lesson 30
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Understand Temperature Scales

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Learning Objectives

  • 1Read both Fahrenheit (°F) and Celsius (°C) scales on a thermometer
  • 2Identify the displayed temperature on either scale
  • 3Recall the key Fahrenheit benchmarks (32, 50, 68, 86, 98.6, 104, 212°F) and the matching Celsius benchmarks (0, 10, 20, 30, 37, 40, 100°C)
  • 4Match everyday scenes to their correct temperature in °F and in °C
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Mini Lesson

Temperature tells us how hot or cold something is. In the United States we usually measure temperature in degrees Fahrenheit (°F). In most other countries — and in science class — temperature is measured in degrees Celsius (°C). A thermometer is the tool we use; many US thermometers show both scales side by side.

Two scales on one thermometer

  • Fahrenheit (°F) — the US everyday scale. Water freezes at 32°F and boils at 212°F.
  • Celsius (°C) — the metric and science scale. Water freezes at 0°C and boils at 100°C.
  • A US wall thermometer often shows °F on one side and °C on the other side of the same column.

Reading a dual-scale thermometer

  • Find the top of the colored liquid column.
  • Read the number on the scale at that level — pick the °F side or the °C side.
  • Higher number = hotter. Lower number = colder.
  • Numbers below the freezing line are written with a minus sign, e.g. -10°F or -5°C (well below freezing).

Key temperature benchmarks (°F primary, °C secondary)

  • 32°F / 0°C — water freezes, ice melts. Very cold — wear a heavy coat.
  • 50°F / 10°C — cool autumn or spring morning. Wear a jacket.
  • 68°F / 20°C — comfortable room temperature. Just right indoors.
  • 86°F / 30°C — warm summer day. Wear light clothing, stay hydrated.
  • 98.6°F / 37°C — normal human body temperature.
  • 104°F / 40°C — very hot day or mild fever. Stay in the shade.
  • 212°F / 100°C — water boils. Extremely dangerous — do not touch!

Quick conversion idea

  • You do not need to do math at Grade 2 — just memorize the benchmark pairs above.
  • Notice: when °C goes up by 10, °F goes up by about 18.
  • A handy fact: 32°F is the same as 0°C — the freezing point of water.
Dual-scale thermometer with Fahrenheit and Celsius benchmarksA vertical thermometer with a shared red mercury column. Fahrenheit labels are on the left side: 32 freezing, 50 cool, 68 room temp, 86 warm summer, 98.6 body temp, 104 very hot, 212 boiling. Matching Celsius labels are on the right side: 0, 10, 20, 30, 37, 40, 100.Dual-Scale Thermometer: °F and °C°F°C32°F freeze0°C50°F cool10°C68°F room20°C86°F summer30°C98.6°F body37°C104°F hot40°C212°F boil!100°C
Dual-scale thermometer — Fahrenheit (°F) on the left, Celsius (°C) on the right, sharing one mercury column.
Everyday scenes matched to Fahrenheit and Celsius temperaturesSix scene cards: snowy day 32°F / 0°C, cool morning 50°F / 10°C, room temperature 68°F / 20°C, hot beach day 95°F / 35°C, body temperature 98.6°F / 37°C, boiling kettle 212°F / 100°C.Scene to Temperature (°F / °C)Snowy day32°F0°CCool morning50°F10°CRoom temp68°F20°CHot beach day95°F35°CBody temp98.6°F37°CBoiling kettle212°F100°CCOLD to HOT32°F / 0°C50°F / 10°C68°F / 20°C99°F / 37°C212°F / 100°C
Six scene cards paired with benchmark temperatures in both °F and °C.
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Ask yourself: "Is the scene cold, cool, warm, or hot? Which °F (and °C) benchmark matches best?"

Vocabulary
Temperature
How hot or cold something ise.g. Today's temperature was 68°F (20°C).
Thermometer
A tool used to measure temperature; US thermometers often show both °F and °Ce.g. The thermometer shows 86°F on one side and 30°C on the other.
Fahrenheit
The everyday US temperature scale, written °Fe.g. Water freezes at 32°F.
Celsius
The metric and science temperature scale, written °Ce.g. Water boils at 100°C.
Freezing
When water turns to ice, at 32°F / 0°Ce.g. At 32°F (0°C) the lake's surface is freezing.
Boiling
When water bubbles into steam, at 212°F / 100°Ce.g. Boiling water can burn you, so be careful.
Body temperature
The normal warmth inside a healthy body, about 98.6°F / 37°Ce.g. Body temperature stays close to 98.6°F (37°C).
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