# Thread: Ball on Bat impact temperature?

1. ## Ball on Bat impact temperature?

Hi Guys,

I'm Paul from West Wales. How are you all? I hope you are well.

Me and my pals have been talking about the Hot Spot technology, and this question came up:

What temperature do you think the ball creates on the bat face on impact?

I understand different speed bowlers mixed with different shots (a fast bowler getting smashed out the middle to cow corner probably creates more friction than a back foot defensive), but what do you guys reckon? How hot will the spot where the ball meets the bat get?

30 degrees C? 40 Degrees?? 55???

On the Hot Spot replays, the temperature of the bare skin of the batsman always looks a lot cooler than the impact of the ball on bat, which leads me to think the 'Hot spot' is around 45 degrees C?

Discuss?! I've done some searching online and I've nothing.

Cheers!

Paul

2. No one??

3. nah dunno

seems high though. I think you might be confusing body temp with skin temp, which could be lower. Wouldn't think the friction would cause much more than a degree or two difference at most.

4. It may be something that is not known. The best article I could find on it was this one and it talked more about pixel intensity rather than actual temperatures.

Hotspot Technology in Cricket

5. Yeah, it's something I cant find any information on. I even contacted the chap at BGG sports who invented the Hot Spot system and they dont know. They said that the camera's are just set to the level, and they dont know what temp that is...

I'm quite surprised to find no-one has done any research into it...

6. Someone who is half decent at Physics could probably calculate you a rough estimate by using a few ugly assumptions, and they'd need to find the right data from TV broadcast records (things like speed of ball leaving bat vs speed of ball arriving at bat). Wouldn't be as good as a real measurement of course.

Not volunteering sorry

7. The speed of the stroke and the weight of the bat would need to be known too wouldn't it..

I don't think it would be hot at all, although my brain isn't really weird for this sort of thing.

8. Great question, would love it if someone smarter than me knows!

Skin temperature is around 37 degrees on average.

Just as a simple exercise, if you quickly and firmly rub your palms over each other once (like if your hands were cold, but only do one quick pressured stroke). you can feel a decent amount of heat generated (hotter than your normal skin surface temp), which then cools quickly.

I'd imagine hot spot would be similar. Maybe a bit hotter than skin temp?

9. Yeah, if you watch the replays on hotspot, and take in to account the colour of the bat, the player's skin, and then the impact area - there may be a correlation there, or a way to work out the temp the impact makes. Obviously as suggested before, on a few assumptions. But I think it could be more than what we think....

10. ...and on another note, who remembers that BURN on their hands after deflecting a seriously hard struck ball?? I do - I had one last night, but it was on the side of my knee!

11. Originally Posted by paologray
...and on another note, who remembers that BURN on their hands after deflecting a seriously hard struck ball?? I do - I had one last night, but it was on the side of my knee!

12. I've got 2 lovely cherries on my right leg from last night. One on the outside of the knee, and the other in the middle of the thigh. Superb! Feel the burn!

13. there is going to be little to no temperature difference as it is just one swift movement.

14. I completely disagree! I think there would be at least a 10 degree rise!

15. Depends what you want to define as temperature really.

In the very small area of impact, the energy given off by the forces acting against each other will cause heat to be created. Thats what hotspot is picking up. Whilst the area it covers is wide (the width of the ball), theres no depth to it (only on the surface of the bat), so the felt heat change will be very low. Also the short period of time the energy is being expelled means the effects are very short lived (a second or two at the most??)

Personally I wouldn't define that as a temperature change though. The measurable effect on the atmosphere around is virtually nil. Its the same for all forces reacting. For example clapping your hands releases energy using the same principles, and if you clap long enough the surface of your hands feels warmer, but the air around them doesnt (ie 100 people clapping wont heat a room)

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