Control
Dillon placed a cardboard sleeve on each of three paper cups. He left three other cups without sleeves. Then, he poured the same amount of coffee into each of the six cups. He measured the temperature of the coffee in each cup every minute for ten minutes.
Cups without sleeve
How many trials should be done for an experiment to be cosidered valid?
Atleast 3
What method is the way to answer questions by making observations and doing experiments?
Scientific Method
Ryan wanted to grow cucumbers from seeds. He read that using a heating pad to heat up potting soil could help make seeds germinate, or sprout, faster. Ryan wondered whether the temperature of the heating pad would affect how quickly the seeds germinated.
temperature
Ryan wanted to grow cucumbers from seeds. He read that using a heating pad to heat up potting soil could help make seeds germinate, or sprout, faster. Ryan wondered whether the temperature of the heating pad would affect how quickly the seeds germinated.
germination time
Jill was using steel to make rusted sculptures. After building each sculpture, she caused it to rust by placing it in salt water for eight hours. Jill wondered if steel would rust faster if she added vinegar to the salt water. She put five of the squares into a tub filled with salt water. She put the other five squares into a tub filled with salt water mixed with vinegar.
Ones she put in salt water
Keith collected nine equally sized sheets of metal: three sheets of copper, three sheets of iron, and three sheets of aluminum. He used the clips to attach each metal sheet, one sheet at a time, to the circuit. For each sheet, Keith used a light meter to measure how much light the bulb produced.
What is the dependent variable?
The light produced measured by the meter.
On a graph which axis is the independent variable?
x-axis
Jaden gathered eight identical bird feeders. He filled four with sunflower seeds. He filled the remaining four feeders with crushed peanuts. Jaden then placed the bird feeders in his backyard. Over the next five days, he counted the number of woodpeckers that visited each bird feeder each morning.
Different type of food
Jaden gathered eight identical bird feeders. He filled four with sunflower seeds. He filled the remaining four feeders with crushed peanuts. Jaden then placed the bird feeders in his backyard. Over the next five days, he counted the number of woodpeckers that visited each bird feeder each morning.
Number of woodpeckers who came to the feeder.
Mason had heard that pruning, or trimming, tomato plants can help tomatoes grow. He wondered if pruning would affect how well his tomato plants grew. Mason chose 24 tomato plants that were similar in size. He pruned an equal number of branches from each of the first 12 plants. He left the other 12 plants unpruned. Then, each week, Mason weighed the tomatoes that he picked from each group of plants.
The plants that did not get pruned.
oel used a dropper to put equal-sized drops of pure water, one at a time, onto a penny. The drops stayed together and formed a dome on the penny's surface. Joel recorded the number of drops he could add before the water spilled over the edge of the penny. Then, he rinsed and dried the penny, and repeated the test using water mixed with hand soap. He repeated these trials on nine additional pennies. Joel compared the average number of pure water drops to the average number of water drops mixed with hand soap that he could add to a penny before the water spilled over.
Can pennies hold more drops of pure water or with water and mixed with hand soap?
What is a hypothesis?
An educated guess
n biology class, Annie learned that ripe fruits produce a gas called ethylene that can cause other fruits to ripen. Annie prepared four paper bags with five unripe avocados in each bag. She added one ripe banana to two of the bags and no bananas to the remaining two bags. After three days, she opened each bag and counted the number of ripe avocados in each bag.
banana bags
Dillon placed a cardboard sleeve on each of three paper cups. He left three other cups without sleeves. Then, he poured the same amount of coffee into each of the six cups. He measured the temperature of the coffee in each cup every minute for ten minutes.
temperature
Jill was using steel to make rusted sculptures. After building each sculpture, she caused it to rust by placing it in salt water for eight hours. Jill wondered if steel would rust faster if she added vinegar to the salt water. She put five of the squares into a tub filled with salt water. She put the other five squares into a tub filled with salt water mixed with vinegar.
Steel put in salt water only
A geoligist is studying the Grand Canyon's rock formation. Is this pure or applied science?
Pure
What should the dependent varible always be?
measurable
Length of the straw
Dr. Alvarado prepared six culture tanks. He filled each tank with the same amount of a mixture of water and nutrients. Then, he added 1,000 live algae cells to each tank and sealed the tank. In three of the tanks, he added C. rotunda cells. In the other three, he added T. cordiformis cells. After five days, Dr. Alvarado measured the amount of oxygen in each culture tank.
Amount of oxygen in the tank.
Corawondered if her plants would be less healthy if she watered them with greywater (used water) instead of tap water. To test this, she placed eight potted petunia plants on her windowsill. For three months, she watered four of the plants with greywater and the other four with tap water. At the end of three months, she counted the number of dead leaves on each plant.
Plants that received regular water
The item in the experiment that is not tested and used for comparoson is called __________________.
the control
How shoukd a hypothesis be written?
In an If...then format with the If part being the independent variable and the then part being you guess.
Farid noticed that some of the footballs his team used during practice were not fully inflated. He wondered whether fully inflated footballs would travel farther than footballs with a lower air pressure.He fully inflated ten of them to an air pressure of 13 pounds per square inch. He inflated the remaining ten to an air pressure of 10 pounds per square inch. He measured the distance the football traveled and then launched the next ball.
the air pressure
Elise divided a large bottle of soda equally among six glasses. Elise added five whole ice cubes to each of the first three glasses while her brother crushed five ice cubes into small pieces before adding them to each of the other three glasses. Ten minutes after all the ice had been added to the glasses, Elise used a thermometer to measure the temperature of the soda in each glass.
Temperature