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A Perfect Score and a Bunsen Burner Marshmallow is the eighteenth episode of the second season of the American sitcom Young Sheldon. The episode aired on April 4, 2019.


Sheldon and George are called into the principal's office. Principal Tom announces that Sheldon has gotten the perfect score on the PSAT and colleges want him and they will pay more. George wants to high five him but is told by Sheldon that his hands may be dirty.

Mary is against shipping Sheldon off to college so early, but George feels its an opportunity the kid mustn’t let go of. Missy is sure mom would win the argument like always and, moreover, her twin brother would perish in college. Mary asks George if he really thinks college is a good idea at this point. George says he wasn't even sure about Sheldon's high school, but here they are year and a half later. Mary tells Sheldon that she appreciates his efforts, but he has to make do with his weekly college lecture with Dr. Sturgis rather than a full time as it'd be hard for them to drive him back and forth everyday. Sheldon suggests Dr. Sturgis could be his guardian. Mary is still not satisfied. Sheldon is upset and asks her what's the point of being intelligent if he can't utilize opportunities like this. It again sparks discussion and they all agree upon doing demo night with Dr. Sturgis. But first he must be asked if he's okay with it.

Meemaw visits Sturgis, who is stoked to be guardian to Sheldon. Meemaw explains it's a big responsibility, but John argues that Sheldon is age ten biologically and that every other way they're the same. They finally agree on the demo night. Mary and George inform Sheldon and he packs up a suitcase with bubbling happiness. The next day Mary drives Sheldon to John's. She asks if he's nervous and recollects how she used to feel nervous when was she had to spend some weekends at her grandparents’ back in her old days. She adds that it's normal to feel freaked as it'll be his first time sleeping away from his mom at someone else's place, all alone. Sheldon assures it'll be fine as Dr. Sturgis would be there as he's like a mom. Mary says nothing. They reach his place.

Mary is awed to see the number of chalkboards around. John explains he even has one in the bathroom so as to not miss out on inspirations. He also adds that dinner is spaghetti and hotdogs with episodes of “Cosmos” on the side. Sheldon feels like he's the luckiest boy in east Texas. Mary reminds about Sheldon's bedtime and takes her leave. She drives home in melancholy. At home, she heads to Missy who's doing her nails. She offers company but Missy's not interested.   Sheldon there is having such fun that he feels like it's a dream. John shares his regular dreams of him fleeing from a giant Praying Mantis. Sheldon asks if its the same insect in which females feed upon males after mating. John concurs. Sheldon now knows why John never got married.   Mary goes to Georgie (Montana Jordan) who's watching TV and asks if he'd like an ice cream parlor visit later with her. He's not interested either.

Sheldon and John next wonder about extraterrestrial life. Sheldon shares how Missy thinks he's an alien. John adds he's felt himself to be outer space-like too but prefers thinking that they're the intelligent original inhabitants and everybody else is an alien. He asks Sheldon if he'd like burning marshmallows on a Bunsen burner as dessert. Sheldon jumps on the idea! They have a blast roasting and John even sings him a cowboy song to add effect to their makeshift campfire.   Mary next goes to Meemaw who's watching “The Wheel” and asks if she wants to go bowling later. Meemaw's not interested. Mary wonders what John and Shelly might be doing. Meemaw is sure they're watching TV sans interruption. Mary leaves her alone, too.   It's bedtime and Sheldon is getting ready. John offers to tuck him in, but Sheldon's apparently is a self-tucker. John hopes he'd get a good score on their demo night. Sheldon says he'd give him 3 out of 3 stars. Happy and satisfied, John retires to his bedroom.   Mary goes to the Spark's with a Rhubarb pie in hand. Brenda is perplexed to see her as they were never the best neighbors. Mary offers to chat over some pie and resolve their differences. Just then Billy shouts that he's bleeding again. Brenda informs Mary that Bobbi stabbed Billy in the leg with a fork. It was plastic fork, but it tore the skin pretty good. She infers that they're preoccupied. Mary understands she's got to leave.

Sheldon's sleep is ruined with dreams of a giant and eerie Praying Mantis lurking about in a lab. He screams on top of his lungs waking up John who hurries, stumbles and falls. We cut to Sheldon waking him up and confirming if there's a concussion. He goes to the kitchen to get him some ice.   Mary finally goes to George who's watching TV. He switches it off and Mary is happy that he at least has time for her. They start kissing and Mary breaks down. She weeps as she misses Sheldon and is afraid he'll never come back. George consoles her saying that he would and moreover they've got Missy and Georgie. Mary continues to cry.   Sheldon is in the kitchen getting ice. There's a kettle boiling water near him. It ignites a napkin kept nearby and the flames leap up. Sheldon is petrified as the smoke alarm starts to blare. We next see the fire services attending the building.   Mary tucks in Missy and next goes to Sheldon who's made up his mind to not leave home again. John blames Meemaw for trusting him with a child and wonders if he's gotten a concussion! Meemaw says she'd never repeat and asks for his symptoms. He says he thinks there's hair on his head. Meemaw gives out a laugh. George is alone in bed. Mary finally comes back to their bedroom. He asks if all are okay, including her. She smiles yes. George tells her that it was pretty decent for him to drive an hour both ways in the same day. Mary guesses the big guy needs a cuddle, too. She calls him closer and gives him a big fat hug!





  • John Sturgis was thrilled having Sheldon stay with for a weekend. But after a day together and sees his true colors that Sheldon is very difficult to live with.
  • John Sturgis had chalkboards about theories in his apartment. Sheldon and Leonard had chalkboards in their apartment.
  • Sheldon won't move out of the house until he is 14 years old when he goes off to Caltech.