SME
Grade 6 Science · Physical Science
Thermal energy and temperature
Use this for “A cold drink at 4 °C warms 0.5 °C each minute. How warm is it after 20 minutes?”
Chart
Time warming: 20 min
Temperature after: 14 °C
Start temperature: 4 °C
Warming rate: 0.5 °C/min
Temperature change: 10 °C
This is an example. Type your own values to start a new problem.
r (°C/min)
×
t (min)
=
c (°C)
s (°C)
+
c (°C)
=
f (°C)
Formulas
0.5 × 20 = 10
Warming rate × minutes = temperature change
4 + 10 = 14
Start temperature + temperature change = temperature after
Assumptions
•
Thermal energy flows from warmer to cooler until both are the same temperature.
•
A cold drink in a warm room warms up. How fast depends on the cup: a thin metal cup lets energy through faster than a foam cup.
•
Warming rate is the degrees gained each minute. It is steady while the drink is much colder than the room, and it stops at room temperature.
Step-by-step
WE KNOW
Start temperature: 4 °C
Warming rate: 0.5 °C/min
Time warming: 20 min
FIND
temperature change, temperature after
Step 1 · Find temperature change
0.5 × 20 = ?
Warming rate × minutes = temperature change
Each minute the drink gains the rate’s degrees, so multiply by the minutes.
Temperature change = 10 °C
Step 2 · Find temperature after
4 + 10 = ?
Start temperature + temperature change = temperature after
Add the gain to where it started.
Temperature after = 14 °C
Check
Put the numbers back in. Both sides should match.
0.5 × 20 = 10 ✓
4 + 10 = 14 ✓
Topic check
See what you know: 5 questions on this topic
New questions each time. Pass to mark it complete.