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# Calculating Speed

Media Type:
Video

Running Time: 3m 00s
Size: 8.3 MB

or

Source: Cyberchase: “A Broom of One’s Own”

### Collection Developed by:

Collection Credits

### Collection Funded by:

Funding for the VITAL/Ready to Teach collection was secured through the United States Department of Education under the Ready to Teach Program.

In this video segment from Cyberchase, the CyberSquad has to find out exactly how fast each of Wicked’s three brooms can go. They set out to calculate the speed per second of each broom using the data they have from their speed tests over a period of five seconds.

Connections

Everyday Math (2004)
Teacher Lesson Guide, pp. 105, 462, 920
Teacher Reference Manual, pp. 145-148
Student Reference Book, pp. 69

Teaching Tips

Here are some Frame, Focus and Follow-up suggestions for using this video in a math lesson.

What is Frame, Focus and Follow-up?

Frame: Jackie says that "speed means how far you go in a certain amount of time." Does that definition make sense? When someone says the speed of a car is 50 miles an hour, what exactly does that mean? How far would a car traveling that speed go in three hours?

Focus: In this segment, watch to see how the CyberSquad use the information they gather about how far each broom travels in five seconds to figure out the distance each broom travels in one second. What computations do they make? Use a paper and pencil to write down the steps of their process.

Follow Up: Who has the fastest broom? What is its speed? If a broom could travel 100 cybermeters in 10 seconds, what would its speed per second be? Why did the CyberSquad want to report the speed per second, instead of the speed per five seconds?

Transcript

MATT: Yeah! And all we have to do to find out how fast the brooms go is to check the speedometer!

INEZ: Um guys, bad news. There is no speedometer!

HACKER: No, no, no! No, no, no! Bring me something more regal! More royal! More kingly! Forget about the wig...where did you get that broom? It looks fantastically fast.

LARRY: It's a Wickedy Broom, sir. You know, the new kind, made by the Wicked Witch.

HACKER: Whaaaat? Wicked's selling brooms?

LARRY: Oh yes. They're totally hot! Everyone has one. Even I have one! Larry reaches for his polka dot one. Wickedy brooms are the best! And so is Wicked. She's the new Queen of Cyberspace!

HACKER: What??? I'm on vacation one day - and Wicked's the new Queen of cyberspace?! There's only one ruler of cyberspace – and that's me!

LARRY: Hmph... No Tip!

INEZ: Okay, let's think. We need to find out how fast these brooms go. And how 'fast' you go means...

DIGIT: Speed! How fast you go is your speeeeeed!

MATT: Yeah! My dad says when our car's speed is sixty miles per hour, it means we'll go sixty miles in one hour!

JACKIE: So your "speed" - means how far you go in a certain amount of time.

INEZ: Like my broom flies from the starting line...to here in five seconds!

JACKIE: But how far is that?

DIGIT: Tape measure anyone?

INEZ: This tortoise is 25 cybermeters from the starting line! How fast did I go? 25 cybermeters in five seconds!

MATT: Man, your broom is sure faster than mine. I only flew 20 cybermeters in five seconds.

JACKIE: I'm even slower than that - 15 cybermeters in five seconds.

DIGIT: Get over it, Jax. At least we found out the speed of each broom. The pink goes 15 cybermeters in five seconds, the green goes 20 cybermeters in five seconds, and the polka dot goes 25 cybermeters in five seconds!

JACKIE: But we can't go on TV and tell everyone how fast a broom flies in five seconds...it sounds too weird.

INEZ: You're right. How fast it flies in one second is way better.

MATT: Yeah. Sounds more like my Dad says, "60 miles per hour"

DIGIT: I'm getting lost here - can't we just use what we know?

JACKIE: Good point Didge. Let's try. We know Inez's broom is the fastest...

INEZ: ...and we know I went 25 cybermeters in five seconds.

MATT: So the question is - how far would she go in one second?

DIGIT: How do you figure that out?! Another race?

MATT: Wait, I think the answer is right here in front of us. This tape is marked off every 5 cybermeters. And there are one, two, three, four, five equal parts between the starting line and Inez's twenty-five cybermeters. Since there are 5 equal parts and she flew for five seconds, then in one second she flew one part and one part is five cybermeters.

INEZ: Which makes my speed 5 cybermeters per second. If your broom went 20 cybermeters in 5 seconds... then you went, 4 cybermeters per second.

MATT: Because 20 in 5 equal parts is 4!

JACKIE: And I went 3 cybermeters per second, because 15 in 5 equal parts is 3!

DIGIT: What a team - sheer genius! Now we know the speed...the distance each broom travels in just one second!

JACKIE: Cool! Let's tell Wicked we're ready to go on TV! How do I look?

Standards

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