Making Connections

An investigation is carried out to determine the effect of exercise on the rate at which a person can squeeze a clothespin.

In this investigation, the independent variable is the

• control

• exercise

• rate of squeezing

• number of participants

An investigation is carried out to determine the effect of exercise on the rate at which a person can squeeze a clothespin.

Muscle fatigue occurs during this activity when

• carbon dioxide is used up in the muscle cells

• simple sugar is converted to starch in the muscle cells

• proteins accumulate in mitochondria in the muscle cells

• certain waste products collect in the muscle cells

An investigation is carried out to determine the effect of exercise on the rate at which a person can squeeze a clothespin.

The experimental results could be made more valid by

• increasing the number of students

• using safety precautions

• using a plastic clothespin

• making a bar graph of the data

  
  

An investigation is carried out to determine the effect of exercise on the rate at which a person can squeeze a clothespin.

The dependent variable for this experiment is the

• time the student was squeezing the clothespin

• number of times the student was able to squeeze the clothespin

• strength of the student

• length of the clothespin

A student lifted weights after school and found that his muscles started to burn. He couldn’t continue to lift the weights after prolonged exercising. This muscle fatigue is most likely due to

• the heart beating too fast and tiring out

• the lungs accumulating oxygen

• lack of oxygen and build up of waste in the muscles

• lack of carbon dioxide in the muscles

A student hypothesized that watching sports on television would cause viewers’ pulse rates to increase. She designed an experiment to determine the effect of watching sports on pulse rate. A group of 200 volunteers took their pulse rates and then watched their favorite sports on television. After the games, they immediately took their pulse rates again. The data collected showed that the pulse rates of some people increased, but the pulse rates of an equal number of people did not change. Although the hypothesis was not supported by the data, the hypothesis is still valuable because it

• may lead to further investigation

• can be changed to fit the data

• is the opinion of the experimenter

• is based on beliefs of the volunteers

If a control group is not included in an experiment, it would be difficult to

• formulate a hypothesis for the experiment

• make observations about the experimental group

• record data in a data table

• draw a valid conclusion

An experiment was conducted to determine the effect of activity on pulse rate. Data were collected and recorded in the table shown.

Which activity most likely corresponds to the pulse rate of the person while sleeping?

• 1

• 2

• 3

• 4

Students were asked to design a lab that investigated the relationship between exercise and heart rate. Heart rate was determined by recording the pulse rate in beats per minute. The students hypothesized that increased exercise results in an increased heart rate. The class results for the experiment are shown in the graph.

Which statement is best supported by the graph?

• Before exercising, the average pulse rate was 65; four minutes after exercising, the average pulse rate was 65.

• After four minutes of exercising, the average pulse rate was 120; two minutes after exercising, the average pulse rate was 120.

• While exercising, the highest average pulse rate was 150; before exercising, the average pulse rate was 65.

• Two minutes before exercising, the average pulse rate was 80; after two minutes of exercise, the average pulse rate was 140

Students were asked to design a lab that investigated the relationship between exercise and heart rate. Heart rate was determined by recording the pulse rate in beats per minute. The students hypothesized that increased exercise results in an increased heart rate. The class results for the experiment are shown in the graph.

Students in a different science class carried out the same experiment. The data they obtained did not support the hypothesis that increased exercise results in increased heart rate. The most scientifically sound way to deal with this situation is to

• write a new hypothesis

• read about pulse rate in a biology textbook

• have the students in both classes vote to decide which hypothesis is correct

• ask students in a third class to do the experiment and see if their results support the hypothesis