An answer to the "When am I going to need this?" question I always heard in science and math class
We've all heard someone ask when they would need to use what they learned in class in the future. So I decided to come up with a simple answer that kids might actually like.
I'm going to use algebra as my example, the one we most commonly used day-to-day, we use it for budgets, shopping costs estimates, etc.; but when you're a kid in high school, (or if you're one of the smarter cookies and learning it in middle school), these examples don't really connect with you yet because you're still a kid and those examples usually apply to adults.
So how might a kid use algebra in a day-to-day fashion?
Simple, video games.
Be it for saving up to buy one, or actually playing one, kids still use algebra all the time without even realizing it. They use it when figuring out how many resources they need for a build or a crafting recipe. It's used when they try and figure out how many quests/adventures they need to go on before they've saved up enough gold for that cool new armor/weapon that they just unlocked in the market. Kids use algebra more often than they think, and that's what you need to point out to them.
This applies to other topics of learning too, in FPS games you use physics every time you shoot a gun (bullet drop for snipers) or throw a grenade, redstone in Minecraft is very similar to programming, building games teach architecture and sometimes even structural engineering. Video games can be a means of learning rather than it's usual portrayal as a harm to learning, so long as you know how to connect the topic to the game.
Objects launched into the air follow the shape of a parabola like in Angry Birds, coordinate systems are also important to have as well.
The video game example is a good one. Video games include calculations for damages and in-game money. Computer and video game graphics need geometry and shapes.
I tutor a lot, and back when I was in middle/high school I would use video games as a means of encouragement by showing them how they already used whatever topic I happened to be tutoring them in all the time.
Though now I'm in college I'm unable to use my video games examples as much, but it still helps from time to time.
While in another teacher's classroom I saw a poster that answered this question in terms of problem solving. It mentioned that you will need to be able to problem solve throughout your life, so every activity and question is practice to do so in the future. I liked that a lot because it could be applied to any content area or grade level.