Every kid wants to have a water gun. A Super Soaker is a popular water gun from the United States. It’s very powerful (强力的) and easy to use. Do you know who made it? A NASA (美国宇航局) scientist.

Lonnie Johnson, 72, is an African American. When he was a child, Johnson wanted to be an inventor. But during the 1960s, many African Americans couldn’t go to university because of racial discrimination (种族歧视).

Johnson’s talent still brought him far. In high school, he made a robot and won the big prize at a science competition. He was the only black student there.

Johnson later went to university and worked for NASA. He helped test the first Stealth Bomb (隐形轰炸机) and many space probes (太空探测器).

But Johnson didn’t forget his dream of becoming an inventor. One day, he had an idea to make a great water gun while taking a shower.

So he put his idea into practice. After many tests, Johnson finally made the Super Soaker.

The toy gun quickly became popular. In 25 years, it has got more than $1 billion (十亿) in earnings.

The Information about Some Great Inventions

Have you wondered what your pets are feeling? When your dog wags (来回摇摆) its tail, does that mean it is happy? A new app called Happy Pets can tell you what’s going on.

The app uses artificial intelligence (AI) to analyze (分析) the facial expressions of cats and dogs. Then it can tell you what breed (品种) your pet is and how it is feeling. It can show the five most common feelings — happy, angry, neutral, sad and scared.

Researchers at the University of Melbourne in Australia developed the app. The key technology used in the app is facial recognition, a common use of AI. We can unlock our mobile phones or enter train stations with facial recognition readers. But this is the first time that the tech has been used with animals.

The app’s AI was first taught to recognize a picture of an animal. Then, it was taught to recognize the facial features (特征) of cats and dogs. Next came the most important step — teaching it to detect emotions based on certain facial features. For instance, if a dog tightens up its eyes and mouth while changing the position of its ears, this means the dog is scared. To master this skill, the AI program “saw” and “read” thousands of example images.

How accurate are the results? The researchers think they are trustworthy since the app has been tested many times. Interestingly, they have found that cats are harder to read than dogs. In the future, the app might also be able to analyze a pet’s body to make its readings more accurate.