A scientist notices that tomato plants growing near a sunny window seem taller than plants farther from the window. She wonders whether the amount of sunlight affects plant growth. She predicts that tomato plants receiving 8 hours of sunlight each day will grow taller than plants receiving only 4 hours. She grows two groups of plants for six weeks and measures their heights. What is the scientist's hypothesis?, Tomato plants need sunlight to survive., Plant height can be measured in centimeters., Plants receiving 8 hours of sunlight will grow taller than plants receiving 4 hours., The plants should be grown for six weeks., A researcher wants to study the effect of exercise on heart rate. He measures the resting heart rates of 20 adults. Each person then walks quickly on a treadmill for 15 minutes. The researcher predicts that their heart rates will be higher immediately after exercising than they were before exercising. Which statement is the hypothesis?, Heart rate will increase after 15 minutes of exercise., Twenty adults will participate in the experiment., Heart rate should be measured before and after exercise., Walking on a treadmill is a form of exercise., A student wants to know whether water temperature affects how quickly sugar dissolves. She believes sugar will dissolve faster as the temperature of the water increases. She places equal amounts of sugar into cups of water at 10°C, 25°C, and 50°C and records the time needed for the sugar to dissolve. Which statement best represents the student's hypothesis?, Each cup should contain the same amount of sugar., Sugar will dissolve fastest in the warmest water., The temperature of water can be measured in degrees Celsius., The student should record how long the sugar takes to dissolve., A farmer wants to determine whether a new fertilizer increases corn production. He divides a field into two equal sections. One section receives the fertilizer, while the other does not. Before collecting any data, the farmer predicts that the section receiving fertilizer will produce more corn. What is the farmer's hypothesis?, Corn production can vary from year to year., Both sections of the field should receive the same amount of water., The farmer will weigh the corn produced in each section., Corn plants receiving the fertilizer will produce more corn than plants not receiving it., Researchers are investigating whether sleep affects memory. They believe that people who get more sleep will remember more information the next day. One group of participants sleeps for eight hours, while another group sleeps for four hours. The next morning, both groups take the same memory test. Which statement is the hypothesis being tested?, People who sleep eight hours will remember more information than people who sleep four hours., Memory tests can measure how much information people remember., Both groups should take the same memory test., Sleep is necessary for good health., Biologists studying a lake notice that the number of a certain species of fish has decreased during years when water temperatures were unusually high. They propose that warmer water may reduce the survival rate of young fish. To investigate, they raise young fish in tanks kept at different temperatures and record how many survive for 30 days. Which hypothesis are scientists testing?, Young fish are more sensitive to environmental conditions than adult fish., Lake temperatures change throughout the year., Fish can survive for at least 30 days in laboratory tanks., Young fish kept in warmer water will have lower survival rates than those kept in cooler water.

Scientific Method

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