# Around how much do hot plate heat knobs increase per number?

• AMan24
In summary: So, if you use the 10 setting, the real temperature is 100x as high as the setting on the knob. When you are working in a repeatable settings (air-conditioned room with a constant temperature, always the same sample/vessel size) you can prepare your own table of what settings to use. Even then occasionally checking if the temperature is what you think it is won't hurt.
AMan24
In my labs we use hot plates with a 0-10 temperature knob. The hot plates don't have a temperature monitor, so i have no idea how hot each number can increase it or how hot it is at the time. Sometimes i have labs where i have to heat something to more specific temperatures or else the reaction will change or it will boil over. My only option right now is to use a thermometer which isn't always practical, and still its easy to mess up.

Is there a general rule with hot plates and the heat knob numbers? I know there might be factors like, room temperature. But I'm not doing anything that requires super precision, so i only really need a decent estimate. The only thing i know is the temperatures are 25°C at "1" and 550°C at "10"

We use these http://www.sigmaaldrich.com/catalog/product/aldrich/cls6795220?lang=en&region=US

Only thing i could think of is heating water and checking the temperature before heating anything important. But i won't have enough time for that. And my professor might say things like "watch it and don't let it boil too violently", but i just feel like there's just too much of a chance of messing up.

Last edited:
AMan24 said:
The only thing i know is the temperatures are 25°C at "1" and 550°C at "10"
.

The temperature of what is 25c at 1 ? ... the temperature of the plate with nothing on it? ...or a small beaker of water ...or a large beaker of water?

The temperature will vary depending what you have on the plate ... a big beaker of water will have a lower temperature because it has a larger surface area and dissipates the heat to the environment more effectively , a small beaker of water will get hotter , for a given setting.

AMan24
oz93666 said:
The temperature of what is 25c at 1 ? ... the temperature of the plate with nothing on it? ...or a small beaker of water ...or a large beaker of water?

The temperature will vary depending what you have on the plate ... a big beaker of water will have a lower temperature because it has a larger surface area and dissipates the heat to the environment more effectively , a small beaker of water will get hotter , for a given setting.

I'm not sure, i got it from the website. I'm assuming its the plate but i have no idea. And yeah the temperature would be different depending on the amount of what I am heating, but I'm asking this for smaller amount substances, i should have specified that.

AMan24 said:
I'm not sure, i got it from the website. I'm assuming its the plate but i have no idea

I see that now from the website "25-550 °C temp. range" ...I would imagine 25c (room temp) is setting zero ... there's no way you can know the temp...every item you put on the plate has different heat transfer properties , only through experience ... as the prof says "watch it"

AMan24
AMan24 said:
I'm not sure, i got it from the website. I'm assuming its the plate but i have no idea. And yeah the temperature would be different depending on the amount of what I am heating, but I'm asking this for smaller amount substances, i should have specified that.

The only way of being sure is to use a thermometer so no maker will give other scale than the power on the plate (which is what these 0..10 marks on the knob really are).

When you are working in a repeatable settings (air-conditioned room with a constant temperature, always the same sample/vessel size) you can prepare your own table of what settings to use. Even then occasionally checking if the temperature is what you think it is won't hurt.

AMan24
You really just need to know your hotplate. IIRC, the scale is logarithmic, not linear.

## 1. What are hot plate heat knobs?

Hot plate heat knobs are controls on a hot plate that regulate the temperature of the heating surface. They are typically numbered from 1 to 10, with 1 being the lowest temperature and 10 being the highest.

## 2. How much does the temperature increase per number on the hot plate heat knobs?

The temperature increase per number on hot plate heat knobs can vary depending on the specific hot plate. However, a general estimate is that the temperature increases by approximately 20-30 degrees Fahrenheit per number.

## 3. Are hot plate heat knobs accurate in temperature control?

In most cases, hot plate heat knobs are not as precise as other temperature control methods such as a thermometer. The temperature on the hot plate may fluctuate slightly, so it is recommended to use a thermometer for more accurate temperature readings.

## 4. Can the temperature on a hot plate be adjusted in between numbers on the heat knobs?

Yes, it is possible to adjust the temperature between numbers on hot plate heat knobs. However, the temperature may not be as precise and may require some trial and error to find the desired temperature.

## 5. How do I know which number on the hot plate heat knobs corresponds to a specific temperature?

Unfortunately, there is no standard for hot plate heat knobs and their corresponding temperatures. It is best to use a thermometer to determine the exact temperature of the hot plate at each number on the heat knobs.

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