- Rectal temperature?

- Yeah, they're usually like, - Let's do it mum.

- No.

No.

(playful music) - Did you know Bethany, that the most accurate way to check your baby's temperature is with a rectal thermometer which goes in the rectum.

- Yes.

I did know, but do you have any tips, like the best way to take a temperature rectally?

Because maybe this is like exclusive to my children.

None of my babies were ever like, "Yeah sure.

Put that up there, I'll cooperate."

- They weren't like, rectal temperature ... - Yeah, they're usually like - Let's do it mom.

- No.

No.

- Just maniac in place.

- Yeah.

- So what's baby's name?

- This is Mia.

This' Mia Baby.

- Mia, Mia Baby.

- Mia Baby - Mia Baby - It's Mia Baby.

- Now with one hand, spread the buttocks, you know where it goes.

You wanna cover that silver tip at the end of it.

- Okay.

(upbeat music) - This is what we usually consider to be the most accurate way to take a temperature, especially in young kids under the age of three months where a fever could be potentially serious.

- Beep.

- Beep.

Baby doesn't have a fever 'cause she's made of cloth.

And in young, young, young babies, we strongly advise using a rectal unless you don't have one.

- If your baby doesn't have a rectum?

- If your baby doesn't have a rectum.

- Then you could use.

- We've got some other problems to discuss.

So next you said your babies sometimes don't like to get rectal temperatures.

You can do an armpit temperature, an axillary temperature.

There you go.

Now make sure you have a good seal.

You're gonna get a beep on this one also.

Now one thing to take note of, is an axillary or an armpit temperature is going to run slightly cooler.

- Okay.

- Than the rectal temperature.

And that same thermometer after you clean it, can also be used as an oral temperature as well.

This is obviously harder to do in younger babies who aren't gonna cooperate.

Do your kids cooperate with oral temperatures?

- With nothing.

- [Both] Nothing.

- Nothing on earth.

(laughing) - But with the kids that do, make sure your kid bites down.

I'm sorry.

Does not bite down.

- Does not bite down.

- But closes his or her mouth down on thermometer.

- When I was little, thermometers were glass with mercury in them.

- Were you little in the 30s'?

- I was little in 1919.

(laughing) - Bethany.

(laughing) - She probably doesn't have a fever, because we've established the fact that she's not human.

Mia you're human.

Shh.

But let's talk about the second most accurate way to check a temperature and that's with a temporal thermometer.

- Okay.

- So ditch that old school oral one.

Temporal.

You're gonna go right in the middle of Mia's forehead.

She doesn't care.

Push the skin button.

You're gonna move along the middle of the forehead towards the top of the ear, stop right at the hairline.

- That's like the easiest.

I can just stick with this, - A lot of parents do like it.

- All the time.

Now let's say Mia is now six months old, you can start checking her ear.

- Can we do your ear temperature?

- How do your kids, - Sure - Deal with your temps?

- They love this.

They like pushing the buttons and doing it themselves.

Like they love this.

- They actually love it?

- They love it.

(laughs) - They're super weird.

- Playtime is take my temperature in the ear mom.

- Take my temperature in my ear.

- Then you're a pro at this.

You wanna make sure you have a good seal so you're using the proper ear thermometer.

What does it say?

- No fever 'cause she's still a doll.

- There's a lot of variation.

You know, children are warmer than adults.

Some people run warmer than others or circadian rhythms.

There's a weather outside.

That's what your kids was wearing.

What I would again worry about, is if your kid looks sick, is acting weird or if the thermometer is kinda reading something higher than 100 range, check out with your doctor.

- Some people just hot, right?

- Some people just hot.

- Some people just hot.

- Maybe not fever high but like, warm.

- All right.

- There's so many different types of thermometers and I know you're all really fascinated about the physics behind these little engineering marvels.

I hear you.

So let's run through them, what they can be used for and how they work.

First off, the regular digital thermometer.

Now this uses an electronic heat sensor to basically measure body temperature.

It can be used in the mouth, armpits and you guessed it, the rectum.

There's a few pros.

It's fast and it's easy.

It's pretty accurate.

However, if you're trying to get an oral reading, it's not as accurate if somebody has to breathe through their mouth.

You need to get that good seal.

They also are battery operated and they can die.

Kinda like this one.

You also have to absolutely make sure you're keeping them clean for obvious reasons when you think about where they go.

You wanna make sure you are using at least a 60% alcohol based solution.

You can use a dilution of bleach also.

Make sure you're not only cleaning and disinfecting the tip, but also the entire body of the thermometer.

Next up is the exhilarating fascinating digital ear thermometer.

To accurately measure temperature inside of an ear canal.

Which is why it's also called a tympanic thermometer.

Here's how it works.

Every object gives off a little bit of infrared radiation.

The infrared radiation coming off the ear canal, goes back to this thermometer.

It hits something called the thermopile.

That infrared radiation then gets transferred into heat, the heat then goes through an electronic sensor and you get a temperature reading.

Now there's a few pros of this.

It's quick and it's comfortable.

It's also really cool too.

But a few cons.

It can't be used in really young children, in their tiny little ear canals and ear wax can also interfere with you trying to get an accurate measurement.

Also as always, you do wanna make sure you are keeping this thing clean, and what you wanna do is just use a little bit of alcohol or a disinfectant solution with a cotton ball or a Q-tip and clean that tip.

But your child is three months old and you wanna use this really cool infrared technology.

Huh, you're in luck because now you have a temporal artery thermometer.

This is like a forehead thermometer a lot of people have seen.

It uses infrared technology to basically take thousands of readings from the temporal artery, and it uses all those readings to give you an accurate measurement.

Obviously this is fast, it's accurate and it's really easy to use.

And you can use it on children as young as three months.

One of the biggest cons however, is it's pretty expensive.

And as always, make sure you're keeping the thermometer clean.

You don't wanna be using on multiple people and spreading germs from one infrared obsessed child to another.

Next step, we have the alcohol thermometer.

You have to make sure you're using an alcohol thermometer designed for humans.

This one is made for a freezer.

Your child is not a freezer.

Now alcohol thermometers basically work because alcohol expands when it gets really hot.

You can actually get a measurement based on the expansion.

Now one downside to it, which may not affect you, is that it doesn't give you an accurate reading past 172 degrees Fahrenheit.

If any human out there has lived with a temperature of 172 degrees Fahrenheit, you're not a human.

(playful music) - Then there's mercury thermometers, which are a relic of the past and now they're like cool vintage medical tools.

So mercury thermometer works similar to an alcohol thermometer.

Basically when the mercury is warm or hot, it expands, it rises on the tube and it gives you a temperature measurement.

Now you should not be using this anymore.

This I should not even be holding and playing with because they can break, the mercury can spill out and it's toxic.

So in the end, don't take thermometers for granted.

Not only are they crucial tools to help you or a healthcare provider monitor your child's health, check for fever, they're also fascinating engineering marvels.

And now anytime you go out, you can talk to people about how much you know about the physics of these little fever monitoring devices and watch yourself get a standing ovation.

But let's say you still wanna get an accurate reading using this very cool infrared technology, voila.

(playful music) Why aren't you going on?

All right cool.

Oh you're in luck.

What the (beeping) But you're in luck.

(soft music)