Lesson 21.3: Real-World Connection

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Scientists Question Home Run Sluggers

Today's professional baseball players hit twice as many home runs as pro players did 25 years ago. Some people say that this is because today's players are better athletes than ever before. Other people say that it is because ballparks are smaller than they used to be. Now scientists at the University of Rhode Island say they know the real reason.

Bouncing Baseballs

The scientists studied baseballs made in the years 2000, 1995, 1989, 1970, and 1963. They found that the newer baseballs bounce higher and more often than the older ones. The scientists pointed out that the windings, or stitches, on older balls were made of wool. In the newer baseballs, the windings are made of a wool and plastic mixed together. Plastic has a higher amount of elasticity than wool has. So, a baseball with high elasticity is bouncier than a ball with low elasticity.

The scientists also found a difference in the pills, or cores, of the baseballs. Pills are made of layers of rubber and cork. Scientists found that balls with the newer pills bounce a lot higher than those with the older pills.

All this evidence hasn't convinced any baseball manufacturers, however. They say that baseballs have not changed much over the last 70 years. But the next time a slugger whacks the ball out of the park, you can ask, “Was that a great batter or just a great ball?”

Word Wise

A person who is paid to do something: Lara has been a professional ice skater for the past three years.

Someone who has trained for, and has become very good at, one or more sports: At the end of the school year, the best athlete on our team gets an award.

Ability of something to return to its normal shape after being squeezed or stretched: My new watchband has greater elasticity than my old one had.

Facts or signs that show that something is true: The pile of crumbs was evidence that the dog found the bag of cookies.

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The word “evidence” is related to another word, “evident.” Something that is evident is easy to see or notice. These sentence starters all use the word evident. Make up two possible endings for each.

  1. Since you got 100% on your test, it is evident that blank.
  2. From the way your mom smiles at you, it is evident that blank.
  3. When you didn't finish your dinner, it was evident that blank.

Data Hunt

Baseball is often called America's favorite spectator sport. But how many people actually went to the games?

Bar Graph entitled “Attendance at Favorite Sports (in One Recent Year)”

Look at the scale along the side of the graph. The letter M stands for millions. So, the scale begins at zero and goes up to forty million!

  1. Which sport did fewer than 10M people attend?
  2. Which sports did more than 30M people attend?
  3. How many attended college football games?
  4. How many attended men's professional basketball games?
  5. How many attended major-league baseball games?