Chigawo cha kutentha ndi kalori (kal chidule). Kalori ndi kuchuluka kwa kutentha komwe kumafunika kuti kukweze kutentha kwa gramu imodzi ya madzi ndi 1 C ( kuchokera pa 14,5 o C mpaka 15,5 o C). Kuchuluka kwa kutentha komwe kumafunika kumasiyana malinga ndi kutentha kwa madzi kosiyana . Pa kutentha komweko, kuwonjezeka kwa 1 C mu kutentha kwa madzi kumachitika pakati pa 14,5 o C ndi 15,5 o C. Chigawo cha kutentha chomwe chimagwiritsidwa ntchito nthawi zambiri, makamaka kuwonetsa mphamvu ya chakudya, ndi kilocalorie (kcal). 1 kcal = 1000 calories. Dzina lina la 1 kcal = 1 Calorie (capital K). Chigawo cha kutentha cha dongosolo la Britain ndi Btu (British thermal unit). 1 Btu = kuchuluka kwa kutentha komwe kumafunika kuti kukweze kutentha kwa paundi imodzi ya madzi ndi 1 F₂ ( kuchokera pa 63 o F mpaka 64 o F₂).
Kutentha kumakhudzana ndi mphamvu, kotero tiyenera kumvetsetsa ubale womwe ulipo pakati pa mayunitsi otentha ndi mayunitsi amphamvu. Kutengera ndi zoyeserera zomwe Joule ndi asayansi ena adachita, zidapezeka kuti ma Joules 4,186 a ntchito ndi ofanana ndi calorie imodzi ya kutentha.
Kalori imodzi = 4,186 Joules
1 kcal = 1000 calories = 4186 Joules
1 Btu = 778 ft.lb = 252 calories = 1055 Joules
(Kalori imodzi = 4,186 Joules ndipo 1 kcal = 4186 imatchedwa kutentha kwa makina)
Chitsanzo cha funso lokhudza kutentha kwa makina
1. 2 kcal (makilocalories) = ….. ma calories ?
Zokambirana
1 kcal = 1000 calories
2 kcal = 2 (ma calories 1000) = 2000 calories
2. Ma calories 4 = ….. ma calories?
Zokambirana
Kalori imodzi (capital K) = 1 kcal = 1000 calories
Ma calories 4 = 4 (ma calories 1000) = 4000 ma calories
3. Ma calories 10 = ….. Ma Joule?
Zokambirana
Kalori imodzi = 4,186 Joules
Ma calories 10 = 10 (4,186 Joules) = 41,86 Joules
4. 5 kcal = ….. Joule?
Zokambirana
1 kcal = 1000 calories = 4186 Joules
5 kcal = 5 (4186 Joules) = 20930 Joules
5. Ma Joules 2000 = ….. kcal ?
Zokambirana
4186 Joules = 1 kcal
8372 Joules = 8372 / 4186 = 2 kcal
2000 Joules = 2000 / 4186 = 0,4777 kcal
