# Amount of watts needed to heat water

• wakejosh
In summary, the conversation is about finding the equation to calculate the amount of power needed to heat a cup of water by a certain amount. The suggestion to use the definition of a calorie leads to a discussion about converting from power to energy using the small calorie definition. The conversation ends with the question of how to convert watts to calories, which is answered by referring to the Wikipedia page.
wakejosh
I have a problem where I have a cup of water and I have to find out how much power I need to generate to heat it by a certian amount. I can't seem to find the equation I need in my book, can someone help me out? thanks.

ok., now I am just trying to figure out how many watts = a calorie. is it 0.239 calories = 1 watt?

Keep in mind that a calorie is a unit of energy, and a watt is a unit of power. Do you know how to convert from power to energy? (hint -- keep track of your units so you don't mix seconds and hours, etc.)

i don't know, how do i convert watts to calories?

wakejosh said:
i don't know, how do i convert watts to calories?

It says how right at the top of the wikipedia page that I posted a link to. Use the small calorie (gram) definition.

## 1. How many watts are needed to heat one gallon of water?

The amount of watts needed to heat one gallon of water depends on the starting temperature of the water and the desired ending temperature. As a general rule, it takes about 8.34 watts to heat one gallon of water by one degree Fahrenheit in one hour.

## 2. How does the wattage affect the heating time of water?

The higher the wattage, the faster the water will heat up. This is because higher wattage means more energy is being transferred to the water per unit of time. However, it is important to note that using a higher wattage can also lead to a higher electricity bill.

## 3. Can I use a lower wattage to heat water?

Yes, you can use a lower wattage to heat water, but it will take longer for the water to reach the desired temperature. For example, if it takes 10 minutes to heat water to a certain temperature using 1000 watts, it may take 20 minutes to reach the same temperature using 500 watts.

## 4. How does the type of container affect the wattage needed to heat water?

The type of container can affect the wattage needed to heat water. For example, a metal or glass container may require less wattage than a plastic container because metal and glass are better conductors of heat. This means they can transfer heat more efficiently and require less energy to heat the water.

## 5. Does the altitude affect the amount of watts needed to heat water?

Yes, altitude can affect the amount of watts needed to heat water. At higher altitudes, the air pressure is lower, which means water boils at a lower temperature. This means it will take less energy (watts) to heat water to its boiling point at higher altitudes compared to lower altitudes.

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