New Blood Pressure Machine

Meghan picked up Grandpa's digital tire gauge last night and wanted to know if it was a new blood pressure machine. Of course I told her yes. She wanted to know how it worked so I told her to put it in her ear and it would measure how much pressure was in her ear.
She is so gullible that she put it in her ear and waited a few seconds, pulled it out and said "it doesn't say anything, Grandma". I told her it would tell her what her pressure was if she just waited a little while longer. So once again in goes the tire gauge into her ear and she waited and waited and nothing happened. So she blew into the tip to see if it was broken. Still no reading. Finally I told her it was the tire gauge that Gramps uses to check the air pressure in the tires.
She is so funny and I thought I was going to burst trying not to laugh at her.